Handbook of Fat Replacers

Library of Congress Cataloging-in-Publication Data Handbook of fat replacers / edited by Sibel Roller, Sylvia A. Jones. p. cm. Includes bibliographical references (p. – ) and index. ISBN 0–8493–2512–9 (alk. paper) 1. Fat substitutes. I. Roller, Sibel. II. Jones, Sylvia A. TP447.F37H36 1996 664′ .3--dc20

95-48346 CIP

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Preface The nutritional need for fat reduction in the Western diet has been recognized for over a decade. However, a thorough understanding of the technical complexities involved in fat reduction in foods has lagged behind. This has constrained work in product development and, in many cases, has led to the development of less than optimal products. Meanwhile, in response to the needs of the food industry, an extensive number of ingredients has been developed solely for the purpose of fat replacement, using a variety of approaches and base materials. In addition, some of the well-established texturemodifying food ingredients have been found to be effective in fat replacement. Thus, over 200 ingredients are now commercially available, or are at different stages of development, that can be used to replace fat in foods. The sheer number of ingredients can be seen as a measure of the difficulties experienced in matching the multifunctional characteristics exhibited by fat in foods, and presents product development teams with a rather onerous task. Meanwhile, the issue of fat reduction remains a priority area from the perspective of both the consumer and the food industry. The purpose of this handbook is to provide, in a single volume, as much information as is practicable on the science and application of fat replacers in food products, including the multiplicity of technological, legislative, sensory, and marketing issues involved in fat replacement. Due care has been given to provide an international perspective and a multidisciplinary approach. The book is intended not only for food scientists and food technologists who wish to formulate new, low-fat food products based on an understanding of the ingredients available, but also for all food industry professionals, including ingredient manufacturers/developers who seek information on latest developments in the industry. Academic researchers and students of food science should also find the book of interest. In short, we hope the book will help fill an important gap in the food science and technology area. Part I of the book, containing five chapters, is an overview of fundamental issues important in the development of low-fat foods and ingredients used to replace fat. This section includes a historical perspective on developments in fat replacers and a critical assessment of available technological strategies, as well as chapters on nutritional implications, marketing considerations, the inter-relationships between physical and chemical aspects of fat replacement and sensory quality, and legislative implications. In Part II, commercially available fat replacers are reviewed individually and in detail. In a book of this size, it is impossible to cover all the commercial fat replacers available today. We have, therefore, selected a limited number of fat replacers each of which is representative of a group of compounds. The chapters are arranged principally according

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to chemical structure, namely, carbohydrate-based, protein-based, and lipid-based. Since a large proportion of the commercial fat replacers have been derived from carbohydrate materials, there are several chapters within this group to represent the different categories — i.e., starches, various fibers, gums and bulking agents. There is also a chapter on combination systems. Combination systems comprise blends of ingredients, the functionality of which develops in situ upon processing, and may be of an interactive or non-interactive nature. Only combination systems based on interactive blends are considered here since systems of a non-interactive nature are merely a sum of the functionalities of the different ingredients used in the blend (possibly with some synergistic effects). Furthermore, synthetic fat substitutes, which have been developed but not so far permitted for use in foods, are discussed. Among the issues covered in each chapter are: history and use of the fat replacer; production process; chemical structure and functional properties; interactions with other food ingredients; nutritional, toxicological, and legal status; and selected examples of food product formulations. The Appendix contains a comprehensive list of fat replacers classified according to their basic compositional parameters, with details on chemical composition, names of manufacturers, applications, etc. This list should allow the reader to look up a fat replacer by trade name, determine its principal composition, and then turn to a chapter in the handbook which describes in detail the fat replacer or one belonging to the same class. For example, a reader wishing to find out more about a fat replacer called Paselli SA2, when referring to the Appendix, will find it among the starch-derived group of fat replacers, and described as being a potato maltodextrin. The reader could then turn to Chapters 6A and 6B for more detailed information on maltodextrins and their role as fat mimetics. It should be noted that the inclusion of a fat replacer in this list does not indicate endorsement of the product nor does absence from the list have any negative implications. Finally, a word of explanation is required regarding terminology. Throughout this book, we have used the term “fat replacer” collectively to cover all fat mimetics and fat substitutes. In this context, the term “fat mimetic” is used to denote those ingredients which modify the aqueous phase of a food, and hence simulate some of the physical properties exhibited by fat. By contrast, the term “fat substitute” is used to denote synthetic ingredients which are purposely designed to replace fat on a weight-by-weight basis (mostly with a chemical structure resembling that of a triglyceride) but with an inherent low digestibility, which makes these ingredients non- or low-caloric, and at the same time stable at high processing temperatures (e.g., in frying). Since fat substitutes so far are not permitted for use in foods*, and this book is intended to be a practical sourcebook, fat mimetics are given most prominence. Last but not least, we would like to thank the authors of the individual chapters for their contributions, without whom a book of this nature could not have been written. Their time and effort spent on the preparation of the chapters, and their endeavors to accommodate our editorial requests, are much appreciated.** Sibel Roller Sylvia A. Jones

* Since completing this manuscript, the U.S. FDA announced on January 24, 1996 their approval for the use of olestra in selected savory snacks. ** Views and opinions expressed by the authors of the various chapters are their own and do not necessarily reflect those of the editors.

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The Editors Sibel Roller, M.Sc., Ph.D., is Professor of Food Biotechnology at South Bank University in London, U.K. Professor Roller obtained her B.A. degree in Biology in 1976 from Hunter College in New York and her M.Sc. degree in Environmental Health Sciences in 1978 from the School of Hygiene and Public Health of the Johns Hopkins University in Baltimore. She then moved to England to obtain her Ph.D. degree in 1981 in Food Microbiology from Queen Elizabeth College (now King’s College) of the University of London. While remaining at the same university, Professor Roller worked for 3 years as a Postdoctoral Research Associate on microbial fuel cells as alternative sources of energy. In 1985, she joined the Leatherhead Food Research Association in Surrey, U.K., where she initiated, developed, and led the research group in the Biotechnology Unit. As Head of the Unit, she was responsible for directing numerous short- and long-term research projects sponsored by the U.K. Ministry of Agriculture, Fisheries and Food, the Department of Trade and Industry, the European Commission, and a range of national and multinational food companies. In 1994, she was appointed to a Professorship in Food Biotechnology at South Bank University. Professor Roller is a Fellow of the Institute of Food Science and Technology (U.K.) and is an active member of the Institute’s Technical and Legislative Committee. She is a member of Sigma Xi, the Honorary Scientific Research Society, and is a Professional Member of the Institute of Food Technologists (U.S.). She is also a member of the Society of Applied Bacteriology and the Society of General Microbiology. Professor Roller currently serves on the Editorial Board of Food Biotechnology and has served on the Public Awareness Working Party of the Bioindustry Association in the U.K. Professor Roller has published over 40 refereed papers and patents and is a frequent invited speaker at international conferences. Her main research interests are in the application of biotechnology to food processing with special emphasis on developing new and upgrading old food ingredients using enzymes and microorganisms. The enzymic modification of food polysaccharides to prepare novel fat replacers, gelling agents, and thickeners is an important focus of her research work. Sylvia A. Jones, M.Sc., Ph.D., is Head of the Food Product Research and Development Department at the Leatherhead Food Research Association, U.K. Dr. Jones obtained her B.Sc. and M.Sc. degrees in Food Chemistry/Food Technology, including specialization in Human Nutrition, at the Agricultural University of Warsaw. She was awarded her Ph.D. degree at Cranfield University, U.K., following research on extrusion cooking technology.

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From 1975 to 1981, Dr. Jones was Lecturer in Food Science and Industrial Food Technology at the Agricultural University of Warsaw, during which time she also acted as a consultant for several food companies in Poland. In 1981–1982, she was Research Fellow in the Department of Food and Nutritional Sciences at Queen Elizabeth College (now King’s College), University of London, where she did research on the rheology of emulsion systems. In addition, between 1979 and 1983, she acted as technical consultant for a number of international food ingredient companies. She joined the Leatherhead Food Research Association as Principal Scientist in 1983, and progressed through Section Manager to Head of Department. Currently, she leads a multidisciplinary team of 26 scientists involved in research and development studies in a wide range of food product areas and novel processing methods. Her department comprises five sections, namely, Food Technology, Product Research and Development, Sensory Analysis and Texture Studies, Nutrition, and Microscopy. Furthermore, during the last 12 years, she has been Research Manager for both the Confectionery Products Panel and the Fruit and Vegetable Products Panel, thus responsible for undertaking research on behalf of some 400 member companies worldwide, and has directed a number of innovative research projects sponsored by the U.K. Ministry of Agriculture, Food and Fisheries, and by the European Union. In addition, over the years, Dr. Jones has developed and considerably expanded research and development consultancy activities at the Leatherhead Food Research Association; at present, a major part of her work is in the form of confidential and proprietary research undertaken for individual member companies. Dr. Jones is a Fellow of the Institute of Food Science and Technology (U.K.), and a Professional Member of the Institute of Food Technology (U.S.). She has been a member of technical committees of several food industry associations, including the U.K. Biscuit, Cake, Chocolate and Confectionery Alliance, the Food and Drink Federation, and the Microwave Working Group led by the U.K. Ministry of Agriculture, Food, and Fisheries. Her achievements in the field of food research were recognized early in her career when she received twice, in 1976 and 1979, respectively, the Rector’s Award at the Agricultural University of Warsaw, and, in 1978, she was presented with the Minister of Science, Higher Education and Technology Award. The main research interests of Dr. Jones have continued to be in the fields of food emulsions, fat reduction, food texture, food rheology, and overall structure/function relationships in foods. She has published and presented over 70 papers and patents, and has been an invited speaker to numerous international meetings throughout Europe, in the Middle East and in the United States. Her first paper on fat reduction in foods was published in 1977. Since then, she has maintained her interest in technological approaches to fat reduction, and, for the last 7 years, her major preoccupation in research and confidential work at the Leatherhead Food Research Association has been concerned with fat replacement and fat replacers.

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Contributors David A. Bell Dow Food Stabilizers The Dow Chemical Company Midland, Michigan

Debra L. Miller Biobehavioral Health and Nutrition The Pennsylvania State University University Park, Pennsylvania

Stuart M. Clegg Food Product Research and Development Department Leatherhead Food Research Association Leatherhead, Surrey, United Kingdom

Helen L. Mitchell Consultant Food Technologist Kent, United Kingdom

Eric Flack Grindsted Division Danisco Ingredients (U.K.) Ltd. Suffolk, United Kingdom Jaap Harkema Business Unit Ingredients for Food and Pharmacy AVEBE Ter Apelkanaal, The Netherlands William M. Humphreys Food Ingredients Division FMC Europe NV Brussels, Belgium Sylvia A. Jones Food Product Research and Development Department Leatherhead Food Research Association Leatherhead, Surrey, United Kingdom Pablo de Mariscal Research and Development Dow Europe, S.A. Horgen, Switzerland ©1996 CRC Press LLC

Guy Muyldermans R & D Laboratory Tessenderlo Chemie n.v. Tessenderlo, Belgium Beinta Unni Nielsen Copenhagen Pectin A/S Hercules Inc. Lille Skensved, Denmark Sibel Roller Food Research Centre South Bank University London, United Kingdom Barbara J. Rolls Laboratory for the Study of Human Ingestive Behavior The Pennsylvania State University University Park, Pennsylvania Norman S. Singer Ideas Workshop, Inc. Highland Park, Illinois Jane Smith Legislation Department Leatherhead Food Research Association Leatherhead, Surrey, United Kingdom

Barry G. Swanson Department of Food Science and Human Nutrition Washington State University Pullman, Washington

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John N. Young Market Intelligence Section Leatherhead Food Research Association Leatherhead, Surrey, United Kingdom

Contents PART I: FUNDAMENTAL ISSUES Chapter 1 Issues in Fat Replacement Sylvia A. Jones Chapter 2 Implications of Fat Reduction in the Diet Debra L. Miller and Barbara J. Rolls Chapter 3 Market Considerations in Fat Replacement John N. Young Chapter 4 Physical, Chemical, and Sensory Aspects of Fat Replacement Sylvia A. Jones Chapter 5 Legislative Implications of Fat Replacement Jane Smith PART II: FAT REPLACERS AND THEIR PROPERTIES Chapter 6A Starch-Derived Fat Mimetics: Maltodextrins Sibel Roller Chapter 6B Starch-Derived Fat Mimetics from Potato Jaap Harkema Chapter 7A Fiber-Based Fat Mimetics: Microcrystalline Cellulose William M. Humphreys

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Chapter 7B Fiber-Based Fat Mimetics: Methylcellulose Gums Pablo de Mariscal and David A. Bell Chapter 7C Fiber-Based Fat Mimetics: Pectin Beinta Unni Nielsen Chapter 8 Microparticulated Proteins as Fat Mimetics Norman S. Singer Chapter 9 The Use of Hydrocolloid Gums as Fat Mimetics Stuart M. Clegg Chapter 10 The Role of Emulsifiers in Low-Fat Food Products Eric Flack Chapter 11 The Role of the Bulking Agent Polydextrose in Fat Replacement Helen L. Mitchell Chapter 12 The Use of Blends as Fat Mimetics: Gelatin/Hydrocolloid Combinations Guy Muyldermans Chapter 13 Low-Calorie Fats and Synthetic Fat Substitutes Barry G. Swanson Appendix Classified List of Fat Replacers and Their Applications Sylvia A. Jones

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Part

I

Fundamental Issues

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Chapter

Issues in Fat Replacement Sylvia A. Jones CONTENTS 1.1 Introduction 1.2 Nutritional Background 1.3 The Functions of Fat in Food 1.3.1 Nutritional Functions of Fat 1.3.2 Physical and Chemical Functions of Fat 1.3.3 Sensory Functions of Fat 1.3.4 Overall Implications for Fat Replacement 1.4 Terminology and Classification of Fat Replacers 1.4.1 Terminology 1.4.2 Classification 1.5 Fat Replacement Strategies 1.5.1 Direct Fat Removal — No Compensation 1.5.2 Formulation Optimization 1.5.3 Technological Approach 1.5.4 Holistic Approach 1.6 Developments in Fat Replacers 1.6.1 Olestra and Its Impact 1.6.2 Maltodextrins and other Starch-Derived Fat Mimetics 1.6.3 Microparticulates 1.6.4 Fat Replacers in the Context of Functional Foods 1.6.5 Recognition of the Role of Established Food Ingredients 1.6.6 Development of Combination Systems 1.6.7 Replacing Standard Fats with Low-Calorie Fats 1.6.8 Improving the Quality of Fat Replacers 1.7 Important Considerations in the Development of Low-Fat Foods 1.7.1 Product Quality/Consumer Preference/Marketing Drive

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1

1.7.2 1.7.3 1.7.4 1.7.5 References

Knowledge of Ingredients Microbiological Implications Legislative Considerations Pricing and Marketing

1.1 INTRODUCTION With over a decade of fat replacement activities in the commercial world behind us, it is appropriate to take a comprehensive view of the principal issues involved, and examine the mechanisms and the directions of the progress made, in order to gain a better understanding of the developments and draw conclusions for the future from the learned experience. As a point of departure, it is useful to address first the principal question: is fat reduction a passing fad? To address this question, we need to look at the nutritional background to this issue, and, in particular, to assess the recent developments in nutrition science. After all, it is the consumption of fat in relation to the etiology of cardiovascular disease that triggered the sudden interest in food products with less fat (or even zero fat), both within the food industry and among the public at large. The challenge has been to produce low-fat variants with physical and sensory characteristics that resemble as closely as possible the full-fat standard products to which people were accustomed. The food industry during the last 10 to 15 years has invested considerable resources and effort into the task. One problem has been that, often, product development has been carried out without a full awareness of the different consequences of removing substantial quantities of fat from a particular product. In order to combat that, and hence develop successfully lowfat variants, it is essential to understand the multiplicity of functions of fat in foods, and, in this context, to examine the particular food matrix in which the fat is to be replaced. Because of the crucial role played by fat in foods, it quickly became obvious that the development of low-fat variants with matching quality of the full-fat counterparts depended on replacing the fat with alternative ingredients. Hence, many ingredients have been developed for the specific purpose of fat replacement. Others are food ingredients that have been used for other purposes before researchers realized that they had a role to play in fat replacement. The result is that over 200 ingredients now exist (either commercially available or at different stages of development) which can be used in fat replacement. The sheer number of ingredients is quite outstanding, but it well illustrates the difficulties encountered in matching the functionality of fat. Indeed, fat can be seen as a “gold standard” similar to sucrose in the case of sweeteners. However, sucrose replacement can now be seen as a relatively easy task compared with fat replacement. With the increase in the number of ingredients available, new terms have been introduced, causing some confusion. Thus, steps need to be taken toward a more systematic approach to both terminology and classification of the ingredients developed for the purpose of fat replacement. Another issue needing consideration is what are the different strategies that can be adopted in product development and how these have evolved and why. A holistic approach to fat replacement needs to be considered, and will be exemplified in Chapter 4 where physical, chemical, and sensory aspects of fat replacement are discussed. Meanwhile, the development of fat replacers has gone through a number of different stages. It is appropriate now to put these developments into a historical perspective and provide a logical framework by identifying the constraints and particular problems of fat replacement,

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and the driving forces behind the developments. This will therefore set the scene for the detailed discussion on the different fat replacers or categories of fat replacers given in Chapters 6 to 13. Last, but not least, when developing low-fat foods, a number of important considerations need to be taken into account. These need to encompass technological, microbiological, and legislative implications, together with marketing aspects, while keeping a watchful eye on changing consumer preferences.

1.2 NUTRITIONAL BACKGROUND Up to the 1970s, the issue of fat in the diet and its effect on health was hardly considered, except in cases of obesity where an overall reduction in energy was recommended. Reduced-calorie foods, therefore, were mainly a small niche market directed toward a minority of consumers who were obese or otherwise wished to lose body weight, and thus were interested in reducing their calorie intake. Moreover, the nutritional advice for weight loss at that time tended to focus more on carbohydrates than on fat, despite the fact that fat is the most dense source of calories (9 kcal/g vs. 4 kcal/g for carbohydrates and proteins). By the 1980s, a radical change had taken place in consumers’ attitudes. This can be traced directly to developments in the science of nutrition, and to a better understanding of the relationships between diet and health, which, in the developed countries, led to significant changes in official nutritional recommendations. In the U.K., this reevaluation was brought to public attention by the publication of two major reports which were, respectively, the so-called “NACNE Report,” produced in 1983 by the National Advisory Committee on Nutrition Education (NACNE, 1983), and Diet and Cardiovascular Disease, known as the “COMA Report,” produced in 1984 by the Committee on Medical Aspects of Food Policy (COMA) (Department of Health and Social Security, 1984). The recommendations of the NACNE Report were oriented toward a diet that would benefit the nation’s health generally, whereas those of the COMA Report were intended more specifically to prevent coronary heart disease (CHD). The major recommendation of both reports was to reduce the intake of fat from the 42% at the time to 34% (NACNE) or 35% (COMA) of total food energy in the diet. Furthermore, they recommended that the intake of saturated fat should be reduced to 10% (NACNE) or 15% (COMA) of food energy. They also advised a reduction in salt intake and increased consumption of complex carbohydrates and dietary fiber. The recommendations were widely debated and given extensive publicity in the media. The reports, therefore, had a significant impact on increasing consumer awareness of the relationship between diet and health. Similar developments took place in the United States. In 1988, the U.S. Surgeon General published a major review on nutrition and health. It proposed that energy in the diet derived from fat should be reduced to 30% (USDHHS, 1988). A further review carried out on behalf of the Food and Nutrition Board of the National Academy of Sciences (NAS, 1989) provided a broad scientific consensus for the U.S. government report: Nutrition and Your Health: Dietary Guidelines for Americans (USDA/USDHHS, 1990). The recommendations of the Surgeon General were supported by a number of health-related organizations such as the American Heart Association and the American Cancer Society, on the basis that the incidence of coronary heart disease and cancer would be reduced by decreasing the amount of fat and cholesterol in the diet (Przybyla, 1990). By the end of the 1980s, the governments of most developed countries in the western hemisphere had drawn up nutritional recommendations advising consumers to reduce fat intake from the prevailing level of 40 to 49% (depending on the country) to

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approximately 30% of total energy in the diet. In most cases, the goal was set to reduce fat consumption to the recommended level by the year 2000. In 1992, the U.K. government issued a set of targets to reduce the incidence of coronary heart disease (CHD) in the White Paper The Health of the Nation: A Strategy for Health in England (Department of Health, 1992). One target was to reduce the number of premature deaths (in people under 65 years old) by 40% by the year 2000 (using 1990 figures as a baseline). Dietary targets were set on the basis of the recommendations given in a second report by the Committee on Medical Aspects of Food Policy on dietary reference values (Department of Health, 1991), which, in the case of fat, was that it should not exceed 35% of total food energy in the diet (the same as in the COMA Report of 1984), with the consumption of saturated fatty acids no more than 11% of total food energy (4% lower than in the COMA 1984 Report). At the time, the average fat intake of the British population was at 40% of total food energy and 17% of food energy was derived from saturated fats. It would appear, therefore, that relatively little progress has been made in achieving the targets suggested by NACNE and COMA in the mid-1980s, despite the concurrent increase in sales of low-fat foods (see Chapter 3). Dietary fat in the American diet is considered to account for 36% of energy content (Buss, 1993), indicating that greater progress in adopting dietary recommendations has been made on average compared with the U.K. However, the analysis of a nutritional survey among British adults (Ministry of Agriculture, Fisheries and Food, 1994a) found that 10% of the adult population had less than 35% of their food energy derived from fat, thus indicating a significant segmentation in consumers’ response to nutritional guidelines. The extent to which consumers might be compensating for low-fat intakes when consuming low-fat products remains to be established (see Chapter 2). If that is so, a further point of interest would be to find out the extent to which the process was a physiological, as opposed to a psychological, response. Meanwhile, scientific research oriented toward understanding better the relationship between diet and health was a major growth area. One noteworthy study was that carried out by Watts et al. (1992), which was the first to support the hypothesis that a low-fat diet can actually prevent narrowing of the coronary arteries. More recently, the complex relationship between diet and heart disease has been reviewed by Ashwell (1993). While it is acknowledged that CHD is a multifactorial disorder, it is considered that diet is one component which can be modified by everybody. The report concludes that the development of CHD can be viewed simplistically as a three-stage process starting from an initial arterial injury that is followed by atherosclerosis and the formation of a blood clot which eventually blocks the artery thus causing a heart attack. Each stage can be influenced by several physiological conditions (e.g., high blood pressure, high levels of plasma lipids, and low levels of antioxidants), and these can be affected by controllable factors, including diet. A “round table model” was derived to elucidate the relationships between the stages of the disease, physiological conditions, and dietary components. The level and composition of the fats consumed is shown to be of importance at all three stages, and overall the dietary advice given includes reduction of fat intake through the consumption of low-fat products and increased intake of fish oils. There is a general consensus that the type of fat consumed is of importance in relation to the aetiology of chronic diseases. In particular, increasing the proportion of polyunsaturated fats in the diet, e.g., through the consumption of oil-rich fish, appears to play a protective role against CHD, as evident from the fact that Eskimos subsisting on a high fat diet based on fish are less prone to heart disease and thrombosis than people on high

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fat diets based more on saturated fats (Dyerberg et al., 1978; Dyerberg and Bang, 1979). The crucial factor, it seems, is the effect of consumption of different fats on the proportion of serum cholesterol associated with high-density lipoproteins (HDL cholesterol) vs. that associated with low-density lipoproteins (LDL cholesterol). Thus, consumption of fats favoring a higher proportion of HDL cholesterol and/or a lower proportion of LDL cholesterol, such as diets in which a higher proportion of fats consumed are polyunsaturated (e.g., from fish or certain vegetable sources) or monounsaturated (e.g., from olive oil), tend to reduce risk from CHD (helped also by the consumption of dietary antioxidants such as Vitamin E, which blocks the oxidative modification of LDL). Conversely, a higher proportion of saturated fats in the diet tends to increase the ratio of LDL cholesterol to HDL cholesterol, thus increasing risk of CHD (Grundy, 1994). However, it is now evident that different saturated fats and dietary sources of saturated fat vary in their influence on the level of LDL cholesterol (Richardson, 1995). For instance, butter and other dairy products, which are high in myristic acid (14:0), appear to strongly increase levels of LDL cholesterol, whereas beef fat, containing palmitic (16:0) and stearic (18:0) acids does so to a lesser extent, and cocoa butter, with a high proportion of stearic acid, increases LDL cholesterol only slightly. In addition, there has been increasing concern and controversy on the consumption of trans fatty acids in relation to health (Mensink and Katan, 1990; Grundy, 1994). Epidemiological data (Willett et al., 1993) have shown a positive association between higher intakes of trans isomers (derived from partially hydrogenated vegetable oils) and the risk of CHD. Wahle and James (1993) have published a comprehensive review on this topic, and concluded that some evidence exists to suggest that trans fatty acids have deleterious effects on blood plasma lipids (i.e., they tend to increase the levels both of LDL and HDL cholesterol present, as well as the concentration of lipoprotein a (which is a genetic marker for CHD acting as an independent risk factor). However, other studies have given conflicting results, so that the issue at present remains unresolved, with a majority of studies implicating trans fatty acids. Clearly, more research is required on this issue. Meanwhile, the FAO/WHO Expert Committee concluded that the effects on plasma cholesterol concentrations exerted by trans unsaturated fatty acids are similar to saturated fatty acids and hence they have recommended that in order to improve plasma lipid profile, the intake of trans fatty acids should be cut back when the intake of saturated fats is reduced (Sanders, 1995). In short, while our knowledge of the relationship between diet and health continues to progress, the adoption of dietary recommendations derived from that knowledge consistently lags behind. It is possible that a better consumer response could be achieved primarily by more extensive nutritional education and secondly, by improving the quality of existing or new low-fat foods. On the other hand, it is likely that as the market matures, with increasing availability of low-fat foods to a wider range of social strata, consumers might more readily adhere to the guidelines regarding fat consumption.

1.3 THE FUNCTIONS OF FAT IN FOOD The level of fat determines the nutritional, physical, chemical, and sensory characteristics of foods. Before the replacement of fat in food products can be considered, however, it is essential to understand what its various functions are. 1.3.1 NUTRITIONAL FUNCTIONS OF FAT Physiologically, fats in foods have three basic functions: they act as a source of essential fatty acids (linolenic and linoleic acids); they act as carriers for fat-soluble vitamins

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(A, D, E and K); and they are an important source of energy. From a nutritional point of view, only the first two may be considered as essential because other nutrients (namely carbohydrates and proteins) can act as sources of energy. Normally, even diets very low in fat can satisfy those requirements. The overriding issue today is that changes in people’s lifestyles over the years have meant that the requirements for energy from food have decreased significantly. At the same time, the proportion of energy derived from fat (the consumption of which, as noted already, apart from being the most concentrated source of energy, has other adverse effects on health) has remained high. Figure 1.1 illustrates the relative contribution of fat from different foods in an intake of 88 g/day which is the average for the U.K., and represents 38% of total energy or approximately 40% of energy from food, i.e., excluding alcohol (Ministry of Agriculture, Fisheries and Food, 1994a).

Figure 1.1 Sources of fat in diet of U.K. consumers. (Compiled from Ministry of Agriculture, Fisheries and Food, 1994a).

The nutritional function of fat in food would not be complete without mentioning its physiological/psychological aspect, mainly the extent to which fat plays a role in achieving satiety. Research has shown that the consumption of fat is associated with a subsequent state of “fulfillment,” such that, by implication, fat reduction might lead to energy compensation and the increased consumption of food. This issue is discussed in detail in Chapter 2. However, it should be pointed out that most studies on satiety have been carried out using noncaloric, nonabsorbable fat substitutes (such as sucrose polyesters). As will be discussed, so far such fat substitutes have not been approved for use in foods, and therefore the studies do not address the current market reality where fat mimetics are used to reduce the fat content of food products. A study on satiety involving three different types of fat mimetics is currently being undertaken at the Leatherhead Food Research Association, supported by the U.K. Ministry of Agriculture, Fisheries and Food.

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1.3.2 PHYSICAL AND CHEMICAL FUNCTIONS OF FAT Physical and chemical functions of fat in food products can be grouped together since the chemical nature of fats determines more or less their physical properties. Thus, the length of the carbon chain of fatty acids esterified with the glycerol, their degree of unsaturation, and the distribution of fatty acids and their molecular configuration (i.e., whether in the form of cis or trans isomers), as well as the polymorphic state of the fat, will all affect the physical properties of foods (for example, viscosity, melting characteristics, crystallinity, and spreadability). Furthermore, fat affects the physical and chemical properties of the product, and hence has several practical implications, the most important of which are (1) the behavior of the food product during processing (e.g., heat stability, viscosity, crystallization, and aerating properties), (2) post-processing characteristics (e.g., shear-sensitivity, tackiness, migration, and dispersion), and (3) storage stability, which can include physical stability (e.g., de-emulsification, fat migration, or fat separation), chemical stability (e.g., rancidity or oxidation), and microbiological stability (e.g., water activity and safety). 1.3.3 SENSORY FUNCTIONS OF FAT Last, but not least, fats have an important function in determining the four main sensory characteristics of food products, which are (1) appearance (e.g., gloss, translucency, color, surface uniformity, and crystallinity) (2) texture (e.g., viscosity, elasticity, and hardness), (3) flavor (namely, intensity of flavor, flavor release, flavor profile, and flavor development), and (4) mouthfeel (e.g., meltability, creaminess, lubricity, thickness, and degree of mouth-coating). Sensory and related aspects of fat reduction are discussed in detail in Chapter 4. 1.3.4 OVERALL IMPLICATIONS FOR FAT REPLACEMENT Reducing fat in a food product must take into account its multifunctional role, in particular how its location in the food matrix determines the chemical, physical, and sensory properties of the food, as well as its processing characteristics. The relative importance of the different functions of the fat in a food vary according to the particular food product and according to the type of fat used. The greater number of product quality characteristics determined by the fat, the more pronounced will be its effect, and the more complex will be the approach required when a substantial part of the fat is to be replaced. In the development of low-fat products, it has been found useful to visualize the overall functionality profile of a product making use of a “fishbone” diagram. This approach was used, for instance, by Loders Crocklaan for designing speciality fats for particular product applications (Anon., 1994). Figure 1.2 illustrates the basic technique whereby a full functionality profile for a given product can be translated into a detailed set of physical/chemical and sensory attributes. By the same token, a detailed functionality profile resulting from the presence of fat in a product can be defined and used as a tool in product development for finding ingredient systems that will deliver the required profile. “Fishbone” diagrams have also been used to illustrate the multifunctional aspects of fat reduction (Anon., 1992).

1.4 TERMINOLOGY AND CLASSIFICATION OF FAT REPLACERS 1.4.1 TERMINOLOGY Over the years, different terms have been used for ingredients that have been specifically developed to replace fat in food products. This has created some confusion over the

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Figure 1.2 Basic fishbone diagram for product development and reformulation purposes. (From Source, Issue No. 13, January, 6, 1994. Reprinted with the permission of Loders Croklaan.)

terminology used for fat-replacing ingredients in the literature. Thus, there is a need to introduce a more systematic approach to this issue. Initially, the term “fat substitute” was used for all such ingredients regardless of the extent to which they were able to replace fat and principles determining their functionality. However, the main interest then had been directed toward discovering an optimal ingredient able to replace fat fully in all food systems. Such an ideal ingredient would need to have a similar chemical structure and similar physical properties to fat, but would need to be resistant to hydrolysis by digestive enzymes in order to have preferably a zero or very low caloric value. In the second half of the 1980s, the only ingredients able to fulfill all those requirements were synthetic compounds such as olestra. The main practical difference between these synthetic compounds and other ingredients launched for the purposes of fat replacement was that only the former were able, by definition, to replace fat on a weight-by-weight basis. All other ingredients, on the other hand, required water to achieve their functionality, and their ability to replace fat was based on the principle of reproducing (mimicking) some of the physical and sensory characteristics associated with the presence of fat in the food. Hence, the term “fat mimetic” evolved to distinguish this group of ingredients. With separate terms now being used to define these different types of ingredients, there was the need for an overall term that referred to all ingredients used for fat–replacement purposes, and the general term “fat replacer” began to be used in that context. However, many authors continue to use the term “fat substitute” for all fat replacing ingredients, and an even greater number use the terms “fat substitute,” “fat mimetic,” and “fat replacer” more or less interchangeably, thus causing confusion on the meanings of these terms. In addition, as a result of further developments, other terms have been introduced by ingredient manufacturers. For instance, the term “fat extender” has been used by Pfizer to describe a system comprising a mixture of ingredients, containing standard fats or oils, such as Veri-Lo® 100 and Veri-Lo® 200, which are emulsions containing 33 and 25% fat, respectively. On the other hand, ingredients such as Caprenin and Salatrim,

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which are true fats (i.e., they are triglycerides) but with a fatty acid composition different from standard fats designed to provide fewer calories (see below), may also be described as “fat extenders.” However, when Salatrim was launched, the term “low-calorie fat” was promoted, and has since evolved as a term in its own right, distinct from “fat extenders.” Thus, Caprenin and Salatrim are now more usually placed in an independent group under the heading “low-calorie fats.” Hence, the term “fat extender” now tends to be reserved for systems combining standard fats or oils with other ingredients, as in the case of Veri-Lo®. In summary, the five terms used to describe ingredients which can replace fat may be defined briefly as follows: Fat replacer: a blanket term to describe any ingredient used to replace fat Fat substitute: a synthetic compound designed to replace fat on a weight-by-weight basis, usually having a similar chemical structure to fat but resistant to hydrolysis by digestive enzymes Fat mimetic: a fat replacer that requires a high water content to achieve its functionality Low-calorie fat: synthetic triglyceride combining unconventional fatty acids to the glycerol backbone which results in reduced caloric value Fat extender: a fat replacement system containing a proportion of standard fats or oils combined with other ingredients

It should be added that the current lack of development activity for the last category of fat replacers might lead to the disappearance of the term in due course; however, it is included in the above list for completeness. 1.4.2 CLASSIFICATION One of the main characteristics of the ingredients used to replace fat is that they lack similarity both in terms of chemical structure and in a specific physical structure. All they have in common is that under certain conditions, they are able to replace fat and fulfill at least some of the functional properties associated with fat in a given product. By definition, therefore, they represent a disparate group of ingredients for which it is not easy to provide a simple classification. An additional problem is that the group as a whole is quite unbalanced in which some subgroups of ingredients of similar chemical structure and functional properties comprise a large number while others may contain only one or two ingredients developed so far. In short, a systematic approach (i.e., based on a single feature or characteristic) cannot be used because too many ingredients would be excluded. Furthermore, there is the issue as to whether to include in any classification all ingredients currently used, or have potential use as fat replacers, or whether it should consist only of those ingredients that have been purposely designed to act as fat replacers. The classification of fat replacers given below aims to give the reader a comprehensive view of ingredient categories that can be considered for product development of low-fat foods (including the synthetic fat substitutes, none of which, as yet, are permitted for use in foods)*. The list is based partially on chemical composition and partially on functionality of the ingredients, and includes combination systems (i.e., blends). 1. Starch-derived 2. Fiber-based * Since completing this manuscript, the U.S. FDA announced on January 24, 1996 their approval for the use of olestra in selected savory snacks.

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3. 4. 5. 6. 7. 8. 9. 10.

Protein-based Gums, gels and thickeners Emulsifiers Bulking agents Low-calorie fats Fat extenders Synthetic fat substitutes Combination systems

As may be seen, a certain degree of overlap cannot be avoided. For instance, it can be debated whether low-calorie fats should be considered as a separate entity, or be included in the synthetic fat substitute category. However, since the low-calorie fats structurally are lipids, and were assigned a separate term from other fat replacers when launched on the market, it is considered more appropriate to differentiate them from the category of the, as yet, unpermitted fat substitutes in the above classification.

1.5 FAT REPLACEMENT STRATEGIES A number of approaches have evolved in the development of reduced-fat foods. In this section, the main options will be discussed briefly in the order that they were introduced. 1.5.1 DIRECT FAT REMOVAL — NO COMPENSATION During the rush of publicity of the new nutritional recommendations in the early 1980s, the first strategy to evolve was simply to remove fat from the standard product, without any attempt to address the organoleptic changes resulting from the reduced presence of the fat. The dairy industry was the first to adopt such a strategy, with the introduction of semi-skimmed, and subsequently, skimmed milk. Fat content was reduced from the 3.5% in the standard product, to, respectively, 1.7% (i.e., a 50% fat reduction) and 0.1% (i.e., a more or less 100% reduction), in effect, replacing the fat with a proportional increase of all the other constituents of milk. This somewhat drastic strategy, which changed considerably the organoleptic quality of the final product, had many skeptics who doubted whether consumers would accept such a change. It was thought that after the initial “hype” period, consumers would gradually go back to the standard “full-fat” milk, and demand for the reduced-fat varieties would dwindle to a small niche market. However, history proved otherwise. In the U.K., for example, as indicated in Figure 1.3, the consumption of reduced-fat liquid milk grew at a remarkable rate. According to the most recent National Food Survey in Britain, the consumption of reduced-fat milk has now overtaken that of whole milk (Ministry of Agriculture, Fisheries and Food, 1994b). In other words, the strategy of direct fat removal adopted by the dairy industry proved a major success, gaining widespread consumer acceptance in spite of the obvious changes in product characteristics. Similar developments subsequently took place in the meat industry. Thus, lean and extra lean raw beef, pork and lamb (mostly in a minced or diced form, chilled or frozen) are now readily available in the supermarkets of many of the developed countries, with a fat content ranging from 15 to 10%, and even as low as 5%. Such a strategy is less possible for most other food products because, for the majority, physical stability, functional properties, and, in many cases, microbiological stability, are adversely affected. The same applies when fat is replaced by water alone. Direct fat removal without compensation, therefore, has limited applicability, depending on the type of product, and the level of fat reduction intended. Since this strategy expects the consumer to accept considerable change in the organoleptic characteristics of a product,

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Figure 1.3 Consumption of liquid milk (g/d) in the U.K. (Compiled from Ministry of Agriculture, Food and Fisheries, National Food Surveys for 1984–1993.)

it can only work well when the consumer is highly motivated, and where, therefore, fat content and nutritional concerns in general will influence purchasing behavior. In short, the limited number of products to which this strategy can be applied has meant that other ways of achieving fat reduction have had to be sought. 1.5.2 FORMULATION OPTIMIZATION The major challenge in the development of reduced-fat foods is to achieve fat reduction while matching as closely as possible the eating qualities of the traditional full-fat product. This involves the creative use of established functional ingredients, including the range of fat replacers now available. For most food products, reduction of fat is associated with an increase in water content. The first need, therefore, in order to mimic the quality of the full-fat product, is to attempt to structure the water phase, through the use of such functional ingredients as proteins, starches and other thickeners, gums, stabilizers, gelling agents, bulking agents, emulsifiers and fibers. The choice of ingredients will depend on product type and the level of fat reduction intended, and needs to be carefully balanced against their effects on the multiplicity of product characteristics. The strategy requires a thorough knowledge of the ingredients available, and an understanding of the structure/function relationships in a given product matrix. During the second half of the 1980s, when the emphasis was narrowly focused on the search for an optimal new fat replacer, developments in other directions were somewhat limited. However, once the inherent limitations of the various fat replacers introduced to the market were realized, interest in the creative use of the standard functional ingredients increased considerably. The introduction of new ingredients designed specifically to replace fat (i.e., fat replacers) significantly increased the scope for matching the quality of reduced-fat variants. Currently, as noted already, there are over 200 ingredients with some claim for

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aiding fat replacement, either available commercially, or at an advanced stage of development (see Section 1.6). Most of the fat replacers on the market are based on the ability to structure the water phase toward achieving fat-like structures that mimic the physical and/or perceived sensory characteristics of fat. 1.5.3 TECHNOLOGICAL APPROACH The use of specially designed fat replacers in products often requires changes in processing conditions or additional processing stages in order to achieve optimal functionality. However, the technological approach can be extended much further in fat replacement strategies. One example would be to explore interactive processing. This is based on the principle of employing a processing method purposely designed to cause interactions between ingredients, and changes in ingredient functionalities within the food matrix, in such a way that they compensate for the removal of fat in the final product. On the other hand, the application of a new technology, or an existing technology that is not normally used in the production of the standard product, can be sought. To date, neither of these approaches has been explored to any great extent. 1.5.4 HOLISTIC APPROACH The holistic approach to fat reduction is based on the fact that, on the one hand, the vast majority of food products are relatively complex systems, and, on the other hand, any one fat mimetic has limitations in its ability to cover the many different functions of fat. The strategy has evolved because in most cases it has been found that no single approach to fat replacement gives a satisfactory final product with significant fat reduction, without compromising some of the quality characteristics (e.g., sensory, physical stability, microbiological stability) of the standard product. It has normally taken the form of using a chosen fat replacer in conjunction with other ingredients (e.g., stabilizers, emulsifiers), or the use of a blend of ingredients designed for a particular product application. More recently, this has shifted toward using more than one fat replacer in conjunction with a range of standard ingredients. However, the ultimate holistic strategy, with the goal of producing optimal quality products with low-fat levels or in fat-free versions, needs to go beyond the issue of ingredients used, toward encompassing all technological means for achieving the required fat reduction. Indeed, this does not only apply to the development of low-fat products, but to all food product development. In a holistic strategy even greater attention must be directed toward achieving an understanding of the functionality of the various ingredients, and how they interact with one another. Many of the advances in product development activities have been predominantly empirically based. In general, low-fat products, because they are deprived of the functionality of fat, are much more sensitive to molecular interactions, especially those between flavor and other ingredients, and those which affect texture. Thus, when developing low-fat products, much more attention needs to be given to all aspects of the often complex and finely balanced physical and chemical system as a whole. This emphasizes the need for a holistic strategy.

1.6 DEVELOPMENTS IN FAT REPLACERS Although the fat replacement issue has been on the agenda for more than a decade, it was not until the late 1980s and early 1990s that the development of ingredients specifically for fat replacement really took off. The fact that there are so many ingredients now available for use in fat replacement means that this has been one of the strongest growth areas in the field of ingredient development for some time. In this section, the various developments in fat replacers are put in a historical context, highlighting the ©1996 CRC Press LLC

main events, in order to show how each development had an impact on further research activities. It sets the scene for the more detailed discussion on the different fat replacers or categories of fat replacers in Chapters 6 through 13. 1.6.1 OLESTRA AND ITS IMPACT Initially, as previously mentioned, the desire was to find an ingredient that would behave, both physically and chemically, like fat, while contributing fewer calories, and which could be used in all product types by directly substituting for the fat, with little or no need to reformulate the product. Olestra, a sucrose polyester, first synthesized in 1968 and patented by the Procter & Gamble Company in 1971, precisely fitted those criteria (Mattson and Volpenheim, 1971). With sucrose substituting for the glycerol moiety in triglycerides, and six to eight of the hydroxyl groups of the sucrose esterified by fatty acids, the chemical structure of olestra is rather similar to fat. The main difference is that the molecule cannot be hydrolyzed by pancreatic lipases, and hence passes straight through the gastrointestinal tract unchanged without being absorbed. It thus contributes no calories. Furthermore, its physical properties could be manipulated by varying the chain length, the degree of unsaturation and the proportions of different fatty acids used to esterify the hydroxyl groups of the sucrose molecule. Finally, because it is inherently heat stable, it can substitute for fat over a wide range of applications in the food industry (including in frying oils), and in virtually every type of food product. It was not until the late 1970s and early 1980s, when the nutritional arguments for reducing fat consumption were being publicized, that a viable market for olestra started to become apparent. Its current status is that it is still awaiting official approval for use in food. Procter & Gamble submitted its first petition for approval to the U.S. Food and Drug Administration (FDA) in April 1987. A further petition was submitted in July 1990, restricting its use to savory snacks (Anon., 1991a). The company has also filed for the approval of olestra in Canada and in the U.K. (Anon., 1990). It was hoped that approval would be obtained in 1995, especially since a second 1-year interim extension to the Procter & Gamble’s patent awarded by the U.S. Patent and Trademark Office is due to expire in January 1996 (Anon., 1995). Under the current U.S. legislation concerning products which require lengthy regulatory review, if olestra were to be approved before this date, then it would be possible for Procter & Gamble’s patent to be extended for an additional 2 years from the time of its approval by the FDA. There is also the issue that even if approved, it is not certain whether olestra will gain consumer acceptance. However, it is noteworthy that, despite, on the one hand, its synthetic nature, and, on the other hand, a concurrent consumer trend in the 1980s toward “natural” and “additivefree” products, olestra has continued to receive remarkably positive publicity. For completeness, it should be added that a number of other synthetic fat substitutes have been developed. These include esterified propoxylated glycerols, carboxy-carboxylate esters, malonate esters, alkyl glyceryl-ethers, alkyl glycoside fatty acid polyesters, esterified polysaccharides, polyvinyl oleate, ethyl esters, polysiloxanes, and many more (Bowes, 1993). These are discussed in Chapter 13. It is interesting to note, though, that none of the companies developing these synthetic fat substitutes have so far attempted to go through the hurdles of gaining approval from the U.S. Food and Drug Administration, but rather have resigned themselves to waiting for the outcome of the application for olestra. However, it should be pointed out that a joint agreement was signed in 1990 between the companies Arco and CPC International to develop esterified propoxylated glycerol, and subsequently to prepare the necessary scientific data required if the ingredient is to gain approval (Anon., 1991a). Meanwhile, the nonavailability of olestra in the 1980s had the effect of stimulating developments in fat replacers in other directions. ©1996 CRC Press LLC

1.6.2 MALTODEXTRINS AND OTHER STARCH-DERIVED FAT MIMETICS In the early days of fat replacement, relatively small reductions in fat were considered an acceptable goal, perhaps by a quarter or a third compared with the fat content of the standard product. In many cases, this could be achieved with the use of different types of starch-derived fat mimetics, which, in contrast to olestra, do not have any regulatory hurdles to pass over. One of the first starch-derived mimetics to enter the market was N-Oil, a tapioca dextrin, which had been produced by National Starch & Chemical Corporation since 1984 (Dziezak, 1989). The most significant amount of research activity on starch-derived mimetics has centered around the development of maltodextrins — i.e., starch hydrolysis products obtained by acid or enzymic hydrolysis of starch materials and characterized by a low dextrose equivalent (DE) value. The concept of starch hydrolysis products with DE<10 was pioneered at the Academy of Science in the former German Democratic Republic, where potato starch was partially degraded using a-amylase, a process that was subsequently patented (Richter et al., 1973). Since such maltodextrins when used in solution at a concentration greater than 20% form thermoreversible gels, with some of the sensory characteristics of fats, and caloric value amounts to approximately 1 kcal/g, there was scope for exploring these ingredients for the purposes of fat replacement. On the other hand, both enzymic and acid hydrolysis methods can be applied to any type of starch or material high in starch content, and hence, not surprisingly, a large number of maltodextrins from different sources have been developed and are available commercially. A detailed discussion of these fat mimetics is given in Chapter 6A, and Chapter 6B covers the maltodextrins derived from potato starch. A list of commercially available maltodextrins is given in the Appendix. Although the main focus was concentrated on maltodextrins, a few modified starches were also introduced to the market for fat replacement purposes toward the end of the 1980s and in the beginning of the 1990s (e.g., the Sta-Slim™ range from the company A. E. Staley and the Amalean range from the American Maize Products Company). Some further developments in starch-derived fat mimetics will be highlighted later. In the late 1980s, when the trend had shifted toward developing food products containing even lower amounts of fat, and in the midst of the “hype” associated with synthetic fat substitutes at that time, fat mimetics, such as those derived from starch, were at a serious disadvantage because they could not fulfill all the criteria for an optimal (ideal) fat replacer. Furthermore, under the influence of olestra, which had been submitted to the FDA for approval, the whole climate of opinion then was dominated by the perceived need to find a single ingredient that had the potential of replacing fat across the whole spectrum of product applications. Thus, fat replacement reached something of an impasse: a market existed for low-fat foods, but while synthetic fat substitutes were not approved for use in food, other ingredients, such as starch-derived fat replacers, could only replace some of the functions of fat in foods, and, as fat mimetics, had restricted applications. 1.6.3 MICROPARTICULATES The first technological breakthrough (or, more precisely, what was perceived as a breakthrough at the time) came with the development of Simplesse®, a microparticulated protein fat mimetic introduced by the NutraSweet Company, the main version of which is based on whey protein concentrate (Singer et al., 1988) — see Chapter 8 for a detailed discussion on Simplesse®. It was launched in January 1988, receiving much publicity in the media. It should be added that while John Labatt Ltd., Canada, the originator of the Simplesse® concept sold the rights to Simplesse® to the NutraSweet Company, further ©1996 CRC Press LLC

developments were on-going at Ault Foods Ltd., a division of John Labbatt Ltd., which culminated in 1989 with the launch of a whey protein concentrate-based fat mimetic under the name Dairylight (Anon. 1991b). The difference between Simplesse® and Dairylight lies in the processing method employed, whereby the latter involves only a mild treatment which leads only to partial denaturation of protein (60 to 80%), and hence it is not a microparticulated protein (Asher et al., 1992). Four years later, in 1993, the company Pfizer relaunched Dairylight under the Dairy-Lo™ name as a result of an agreement reached between Pfizer Company and Ault Foods Ltd., whereby Ault Foods would produce Dairy-Lo™ and Pfizer would market it in all countries with the exception of Canada (Anon., 1993). The concept of a microparticulated protein as a fat mimetic was seen by many as the ultimate development in ingredient technology with the potential of resolving all the problems associated with fat replacement, including that of total fat replacement. These beliefs were compounded by the strong marketing strategy of the NutraSweet Company. However, strong marketing was needed at the time in order to combat the general opinion that fat mimetics were by definition underperformers as compared with the “true” fat replacers such as olestra which, in spite of their failure to gain approval for use in foods, were still seen as the ideal fat replacers. The concept of a special processing method leading to a microparticulated form of an ingredient was seen as one that can actually mimic the fat droplets in an oil-in-water emulsion, and hence the developments in proteinbased fat replacers were oriented toward some form of microparticulates (see Chapter 4 for a more detailed discussion of this issue). While LITA® (from the company Opta Food Ingredients, Inc.) and Trailblazer (from Kraft General Foods) followed this concept using multicomponent systems based on proteins, a large number of insoluble fat mimetics also started to be marketed as having what had become the fashionable microparticulated form (e.g., the Avicel® range from FMC, and Stellar™ a crystalline starch from A. E. Staley). Back in the late 1980s, Simplesse® was also promoted on the basis of its natural (as opposed to synthetic) character, since it was produced from a well-recognized natural ingredient (i.e., whey protein concentrate or egg white/skimmed milk/sugar/pectin for Simplesse® 100 and Simplesse® 300, respectively). The fact that these ingredients were originally produced only in a liquid form, and hence had a short shelf-life and required refrigeration was probably (at least initially) a contributing factor to the positive image of these ingredients. (Further developments of Simplesse® 100 are outlined in Section 1.6.8.) However, in due course, the publicity surrounding Simplesse® turned into a two-edged sword, since it was loaded with high levels of expectancy and hence was thought able to deliver much more than other fat mimetics. In many applications, however, it was not technically possible for it to come up to those expectations, and moreover, it was becoming increasingly apparent that in order to achieve a significant fat reduction, in most cases, other ingredients were also necessary for obtaining optimal quality. 1.6.4 FAT REPLACERS IN THE CONTEXT OF FUNCTIONAL FOODS The link between fat replacers and functional foods has not previously been made. However, that an association does exist, as will be demonstrated here, is worth pointing out amidst the current high level of interest in functional foods. One definition for a functional food states that it is a food which positively affects physiological functions of the body in a targeted way as a result of it containing ingredients which may, in due course, justify health claims (Roberfroid, 1995). Taking this issue broadly, it can be argued that all foods with reduced fat content can be considered as functional foods given the nutritional benefits of fat reduction as discussed in ©1996 CRC Press LLC

Section 1.1. Most of the ingredients used to replace fat, of course, do not provide any special positive physiological benefits themselves. However, fiber-based fat replacers can claim such benefits since there is a growing recognition for the role of dietary fiber in disease prevention, particularly in relation to colonic cancer and heart disease (e.g., Asp et al., 1993; Stark and Madar, 1994; Kritchesky, 1994). Thus, a number of fat replacers have been launched based on fiber from a number of different sources, such as oats, sugar beet, soy beans, almonds, and peas. For instance, Advanced Oat Fibers manufactured by the company Williamson Fiber Products in Ireland were first introduced in 1988. Oat fiber is also a good source of b-glucan which is claimed to have cholesterol-lowering properties (Duxbury, 1990). Oatrim fat replacer, developed and patented by the U.S. Department of Agriculture is obtained through the enzymic modification of oat starch in the oat flour or bran, and contains from 1 to 10% of bglucan (Inglett and Grisamore, 1991). Both ConAgra and Rhône-Poulenc/Quaker Oats Company are currently producing Oatrim under separate license agreements. Another fiber ingredient, Fibercel, developed by Alpha-Beta Technologies, is composed of 85 to 90% β -glucan obtained from a food-grade yeast product (Jamas et al., 1990). A range of cellulose-based fat replacers should also be mentioned as a source of fiber (see Appendix). Moreover, in the particular case of inulin fat replacers (for instance Raftiline® from Orafti, Belgium, and Fibruline® from Cosucra SA, Belgium), positive physiological benefits arise from their bifidus stimulating properties (Roberfroid, 1995). 1.6.5 RECOGNITION OF THE ROLE OF ESTABLISHED FOOD INGREDIENTS Gradually, the realities of the market place began to shift away from the mythical “one ingredient can solve it all” and toward a more holistic strategy. Moreover, meanwhile, commercial pressures were moving the goal-posts of fat reduction to well beyond the 50% mark, thus making it even more difficult to achieve fat replacement without a holistic strategy in which ingredients such as, gums, emulsifiers, thickeners, stabilizers, and bulking agents, along with gelatin and other proteins and untreated starches could play crucial roles. Previously, this group of ingredients had been overshadowed by the orientation toward discovering the “optimal” fat replacer. However, the important role of these well-established ingredients is clearly evident when examining low-fat or zero-fat products currently on the market (Bavington et al., 1992). While in many cases, these ingredients are used in conjunction with those developed purposely for replacing fat, in some products, fat reduction has been achieved by structuring the water phase using only gums and stabilizers (e.g., Kraft’s “Free Choice” Vinaigrette Style Fat-Free Dressing). Thus, the role of ingredients such as gums, stabilizers, thickeners and emulsifiers needs to be firmly emphasized in the context of fat replacement. That is why this group of ingredients has been placed in a separate category in the classification of ingredients given earlier. Details on the uses of gums, bulking agents and emulsifiers are given in Chapters 9, 10, and 11, respectively, and cellulosebased stabilizers, and their use for fat mimicking purposes, is discussed in Chapters 7A and 7B. The scope for utilizing functional food ingredients in fat replacement was further highlighted in 1991 by the commercialization of Slendid®, a proprietary pectin developed by Hercules, Inc., and marketed by Copenhagen Pectin A/S (see Chapter 7C). 1.6.6 DEVELOPMENT OF COMBINATION SYSTEMS The launch of the N-Lite range of fat mimetics by National Starch & Chemical Corporation in January 1992, as well as widening the scope for the use of starch-derived ingredients for fat replacement purposes, was of considerable significance because it established a new trend. This was the development of combination systems (i.e., blends ©1996 CRC Press LLC

of ingredients) for use in fat replacement in specific product applications. For example, N-Lite F, specifically designed for use in icings, fillings, frozen desserts and dry mixes, was a blend of modified starch, non-fat milk solids, polyglycerol ester and guar gum. In effect, therefore, the necessity for the holistic approach to fat replacement has been acknowledged. Most notably, it was in this context that modified starch was shown to have a useful role in fat replacement. In fact, some blends were on the market before 1992. Indeed, a number were launched in the second half of the 1980s, but received few headlines, because, at the time, the search for the single “magic” ingredient was the dominant theme. Developments in the use of blends as fat replacers have taken a number of forms, but, in the main, the approach has been to prepare a formulation containing three or more ingredients which, either could be more universally applied, or, were designed for a specific product category. The latter approach has tended to dominate (for obvious reasons), and the blends typically included as ingredients are gums, stabilizers, thickeners, and emulsifiers, together with standard protein sources (see Appendix for a list of blended ingredient systems that are on the market). Most combination systems are composed using a passive approach, whereby each ingredient has its particular functionality, and it is the sum of those functionalities that is devised to result in optimal product characteristics. However, one group, interactive combination systems, is based on the principle that a particular combination of ingredients interact during processing, resulting in different characteristics to those that would have been expected from each of the ingredients separately or together. A good example of an interactive combination system is the Slimgel® range launched by P.B. Gelatins, Belgium, at the end of 1993. It is composed of gelatin and galactomannans, and its performance is based on thermodynamic incompatibility between these two hydrocolloids, which, in turn, leads to phase separation (Muyldermans, 1993, see also Chapter 12). The advantage of blends, ideally, is that they shorten the time and effort required to develop new low-fat or fat-free products. However, the disadvantage is that when significant development work is required to best match a given full-fat variant, the use of a blend might prove too inflexible, and inhibit the ingredient optimization process, since the precise composition of the main functional system used is not known. The concept of using a range of ingredients in an attempt to reproduce the different functions of fat in the full-fat product goes some way toward a holistic strategy. This was particularly necessary by early 1990s, by which time, partly due to commercial pressures and partly due to new legislative restrictions regarding claims (see Chapter 5), the goal-posts for fat reduction had moved yet again, this time toward the ultimate limit — i.e., zero fat. 1.6.7 REPLACING STANDARD FATS WITH LOW-CALORIE FATS The concept of replacing fat with a low-calorie fat entered the scene in the early 1990s. By that time, the likelihood of obtaining FDA approval for the use of olestra within a short time-scale was dwindling rapidly, and, on the other hand, it was recognized that the commercially available fat mimetics did not provide an easy answer to fat replacement, and, moreover, their use was restricted, in general, to water-based food systems. In this context, the idea of using the basic structure of a triglyceride molecule, but changing the composition of the fatty acids esterified with the glycerol backbone in order to achieve caloric reduction appeared to be very plausible. Moreover, the fact that medium-chain triglycerides, which usually comprise caprylic (C8) and capric (C10) fatty acids, are GRAS ingredients with a 35-year track record in clinical medicine (e.g., for treating patients suffering from lipid malabsorption symptoms or for use in infant formulae) was a distinct advantage (Latta, 1990; Megremis, 1991). These compounds provide energy (8.3 kcal/g) but are metabolized through the liver, and are characterized ©1996 CRC Press LLC

by a low tendency for becoming incorporated into tissue as depot fat. Currently, mediumchain triglycerides are marketed by the U.S. company Karlshamns Food Ingredients (Captex 300, 350 and 355, now known as AKomed range) and by Stepan Company (Neobee® M-5). However, as pointed out by Thayer (1992), there are certain limitations to the use of medium-chain triglycerides in foods since, upon hydrolysis, the free fatty acids released give strong off-flavors. The concept of using medium-chain triglycerides together with long-chain fatty acids (e.g., behenic acid — C22) was developed jointly by Procter & Gamble and Grinsted Products, Inc. and commercialized under the name Caprenin. The incorporation of behenic acid (which is only partially absorbed in the gut), together with caprylic and capric acids, gives further caloric reduction, and the net result is that Caprenin provides only 5 kcal/g (Peters et al., 1991; Webb and Sanders, 1991). More information on Caprenin is given in Chapter 13. Caprenin has been used commercially as a substitute for cocoa butter in the product Milky Way II produced by M & M Mars (introduced into a test market area in the U.S. in March 1992), and (in September 1992) in Hershey’s Reduced Calorie and Fat Candy Bar. In both cases, the Caprenin was used in conjunction with polydextrose to achieve a 25% reduction in caloric value compared with the standard product. However, since then, there seems to have been no apparent progress in the use of Caprenin as a fat replacer. The most recent addition to the low-calorie fat category is Salatrim, developed by Nabisco Foods Group in conjunction with Pfizer Food Science, and launched in July 1994. Salatrim is a family of triglycerides comprising mixtures of long-chain fatty acids (predominantly stearic acid) and short-chain fatty acids (mainly acetic acid, propionic acid, and/or butyric acid) esterified with glycerol. As a result of this chemical structure, the caloric value of Salatrim is 5 kcal/g (Smith et al., 1994). It is not expected that the commercial availability of Salatrim will be hindered by the FDA approval process since it is made from natural substances commonly used in foods and produced by an established interesterification process (petition filed with the FDA in mid-1994). No toxic effects were observed in animal studies of up to 13 weeks duration and in clinical studies, Salatrim was found to be well tolerated in doses of up to 30 g/d (Smith et al., 1994). At the time of writing, Nabisco was hoping to launch chocolate bars containing Salatrim by mid-1995, and Pfizer Food Science was planning subsequently to launch ice cream, cheeses, baked goods and table spreads made from Salatrim. However, the incorporation of Salatrim into frying oils has not been suggested (see Chapter 13). The future will show whether low-calorie fats will be seen as a commercially viable option for the food industry. 1.6.8 IMPROVING THE QUALITY OF FAT REPLACERS Developments of fat replacers have not only been confined to the development of new ingredients. In addition, much effort has been made by ingredient manufacturers to improve further the quality of the existing fat replacers in terms of their functionality, ease of use and heat stability, with the aim of expanding their industrial applications. Three trends can be identified: instantization; alterations in functionality profile; and ease of use during product manufacture. Instantization is an obvious and well-established route for ingredient extension. Thus, a number of ingredient manufacturers have launched instant versions of their fat mimetic. This is evident from the list of fat replacers given in the Appendix. The second trend can be seen as a reflection of the realization that no fat mimetic, however good, can mimic all the functional characteristics provided by a fat in a given product. Thus, one or more other ingredients were being added to alter and improve the

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functionality profile provided by the original ingredient in order to obtain some additional “fat-like” property (e.g., development of the Novagel™ range of fat replacers by F.M.C., based on Avicel®). The extreme form of this trend was its extension into the development of blends, as discussed above. The need for ingredients which were easy to use during the manufacture of food products was especially in evidence during the first half of the 1990s. This is associated with the fact that the use of many of the fat replacers that have been developed necessitated either the preparation of a solution and/or special processing when placed in solution, prior to addition to other ingredients, e.g., the Rafticreming stage required for Raftiline®, and the high shearing (8000 psi) required for Stellar™ (Pszczola, 1991). Hence, the subsequent developments aimed to remove these additional stages in product manufacture while providing the expected functionality, and new variants entered the market (e.g., Raftiline® HP and Instant Stellar™). In the overall context of improvements in the quality and flexibility of fat replacers, Simplesse® deserves special mention, since the original ingredient (Simplesse® 100) which was commercialized in a liquid form (42.5% solids) with a short shelf-life and low heat resistance, was developed into a dry form (Simplesse® 100D) able to withstand UHT pasteurization or retorting, without loss of functionality.

1.7 IMPORTANT CONSIDERATIONS IN THE DEVELOPMENT OF LOW-FAT FOODS A reduced-fat food product, when compared with the standard product it is replacing, more often than not has different requirements from the points of view of manufacturers, retailers, and consumers. For instance, a change in the technology used in manufacture and manufacturing practice may be required, which, furthermore, might have cost implications. A change in pack design, e.g., with improved barrier properties, greater physical protection or a reduced pack size, may be called for where shelf-life is reduced. In some cases, changes in temperature or timescale of distribution may be necessary. While achieving optimal product quality is obviously the primary consideration in the pursuit of fat reduction, it is crucial to base this on an understanding of how the ingredients function, and, taking into account microbiological and legislative implications, appropriately designing a marketing strategy. These issues are highlighted in the following discussion. 1.7.1 PRODUCT QUALITY/CONSUMER PREFERENCE/MARKETING DRIVE Clearly, the organoleptic properties of the low-fat product ultimately determine the success or failure of the product, since consumers are unlikely (at least in the first instance) to sacrifice taste and quality in order to reduce calories in their diet (see Chapter 4 for a detailed discussion on sensory aspects of fat reduction and flavor release). However, the success of the dairy industry in applying the strategy of direct fat removal, which, as noted already, resulted in dramatic organoleptic changes, suggests that consumer perceptions and liking of high-fat products can be modified over time. Indeed, there is already some evidence that consumer preference is shifting toward products with a medium, as opposed to those containing a higher level of fat (Wyeth and Kilcast, 1991; Mela and Marshall, 1992). In other words, consumers’ attitudes to health and diet are apparently beginning to have a significant influence on food choice, and a greater desire for foods with healthier nutritional characteristics is starting to influence organoleptic preferences. Thus, increased consumption of some low-fat product variants can cause changes in preferences, which, in turn, changes acceptability patterns. It can be argued,

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therefore, that for these patterns to emerge, the quality of the products with medium fat reduction may be the key to future developments. In this context, the market drive for fat-free variants may be seen as being premature for some product categories. The positioning of a particular product in the diet should, in principle, determine the level of fat reduction required and the product quality that can be achieved at different fat levels should be balanced against that before making a marketing decision. This helps to explain why some of the fat-free variants, despite apparently different characteristics from the equivalent standard product, appear to be of greater appeal to consumers than others. 1.7.2 KNOWLEDGE OF INGREDIENTS When developing a product where fat reduction is achieved through the incorporation of a fat replacer, it is of considerable importance to know or establish: first, the physical and chemical characteristics of the functional ingredients used; second, what the possible interactions with other food components might be; and third, what the implications might be for the processing operations, i.e., what changes in processing might need to be employed in order to achieve maximum functionality. Thus, a full knowledge of a range of fat replacers, which can be used effectively to narrow down the number of fat replacers suitable for a particular product type, is essential if product development is to be carried out in an efficient manner. Moreover, any adjustments in other ingredients present in the standard full-fat formulation need to be guided by a knowledge of their functionality. It is important to be especially flexible as far as the processing method is concerned, since, in some cases, small adjustments in the standard method might be required, whereas in others, the optimal solution might be to consider other technological options (e.g., through technology transfer, or by devising a new technology altogether). 1.7.3 MICROBIOLOGICAL IMPLICATIONS A reduction in fat content in a given product formulation is usually associated with a simultaneous increase in moisture content, which thus affects microbiological stability, and hence the safety of the product must be given due consideration. For example, lowfat spreads require the addition of a preservative such as potassium sorbate which is not normally necessary for full-fat margarine, and, moreover, they have a considerably shorter shelf-life. Similarly, many low-fat dressings, unlike the full-fat equivalent, require refrigeration after opening. In other words, for many reduced-fat products, consumers have to change the way in which they use the product compared with the full-fat equivalent, and it has to be ensured that consumers are aware of that. It is well recognized that water activity, acidity, preservatives, and the extent of heat treatment are the main factors affecting product shelf-life and microbiological safety. However, it should be mentioned that although water activity measurements have been used in the food industry for nearly 40 years as a food safety parameter, this is now considered inadequate by some, who argue that greater emphasis should be placed on glass transition temperature (Slade and Levine, 1991; Franks, 1991). Franks (1991) suggests that change in water availability, especially in the case of intermediate or low moisture products, is related to the rate of water diffusion in the product, which, in turn, is related to the glass-rubber transition of the material and the sensitivity of the transition temperature to changes in the moisture content. As yet, there is no consensus on this topic. Meanwhile, therefore, water activity remains the basic method for ascertaining microbiological stability.

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In many low-fat products, increasing the acidity of the aqueous phase can be an effective means to achieve an acceptable shelf-life. For example, Gram-negative pathogens such as the salmonellae may be controlled by ensuring a pH below 4.0. For coliforms, an even lower pH is required, or a combination of low pH and low temperature (The International Commission on Microbiological Specifications for Foods, 1980a). The type of acid used for lowering the pH is critical, since it is the undissociated molecule of the organic acid or ester that confers antimicrobial activity. Organic acids used as food preservatives have pKa values of between 3 and 5 (pKa is the pH at which 50% of the total acid is undissociated). Lowering the pH of a food increases the proportion of undissociated molecules of an organic acid, thus increasing its effectiveness as an antimicrobial agent (The International Commission on Microbiological Specifications for Foods, 1980b). Acetic, citric, lactic, propionic, benzoic, and sorbic acids are the most commonly used food acidulants and preservatives. At pH 4.0, for instance, the proportion of acetic acid molecules in an undissociated state is over four times that of citric acid, which reflects the former’s greater effectiveness as a preservative. This is well illustrated by the occurrence of outbreaks of Salmonella in Spain associated with the practice of using lemon juice instead of acetic acid in mayonnaise in which the importance of selecting the right acid to maintain a preservative function was simply overlooked (Perez et al., 1986). In a later study (Perales and Garcia, 1990), it was found that 45% of mayonnaise made in different restaurants in Spain had a pH greater than 4.5, with 17.5% using vinegar and lemon, and 2.5% did not use any source of acid, and 60% of the restaurants surveyed had recipes that allowed Salmonella enteriditis to survive, thus presenting health risks to consumers. The importance of selecting the right acid is even more important in the case of reduced-fat products, where microbiological risks are that much greater. Finally, it is important to bear in mind that if strongly acidic notes perceived in a product adversely affect overall sensory quality, it is possible to design blends that produce an acceptable flavor profile, while maintaining the preservative function. 1.7.4 LEGISLATIVE CONSIDERATIONS When developing reduced-fat variants, the legislative issues in the country of sale need to be taken into account. This topic is discussed in detail in Chapter 5, but here the issue of nutritional claims will be outlined briefly due to its importance in product marketing. In the European Union, harmonized provisions for nutrition claims across the member states has been under consideration for some time now, but final agreement has yet to be reached. The current draft proposes that the term “reduced-fat” can be used if the fat content is reduced by at least 25% of that present in the standard product, and that the “low-fat” claim can only be used if not more than 3 g of fat is present per 100 g of product. The term “without fat” would be considered acceptable if the amount of fat did not exceed 0.15 g per 100 g in a product. However, in the absence of harmonized European Union regulations, national regulations or guidelines need to be adhered to. The U.S. regulations for nutrition claims produced by the FDA differ from the current draft for the European Union in the way the latter two claims are defined. The FDA “low-fat” claim can be used if a reference amount customarily consumed is greater than 30 g, or greater than two tablespoons, and the food contains 3 g or less of fat per reference amount. In cases where the serving size is 30 g or less, or up to two tablespoons, a “lowfat” claim can be used under the conditions stated above, but providing that 3 g or less of fat is present in 50 g of the food. The “fat-free” claim can be used when the food contains less than 0.5 g of fat per reference and per labeled serving.

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A further important difference between current regulations in member states of the European Union and the U.S. is that in the former nutritional labeling remains voluntary unless a nutritional claim is made for the particular food, whereas the U.S. Nutrition Labeling and Education Act as from May 1994 amended the Federal Food, Drug and Cosmetic Act to make nutrition labeling mandatory for most foods, and it also became compulsory to state on the label the amount of calories from fat in addition to the total amount of calories present. Furthermore, where regulations exist regarding compositional requirements, as with butter, chocolate, or ice cream, the reduced-fat product necessitates careful naming and labeling from a legal standpoint. 1.7.5 PRICING AND MARKETING The cost of ingredients used to replace fat is another important factor in the development of low-fat foods. More often than not, product development activities are carried out within financial constraints which require costs of those ingredients not to exceed the cost of the fat they are supposed to replace. Although the initial prices of most fat mimetics have often been relatively high, competition and economies of scale have usually brought prices down over time. However, in order to survive in the market, an ingredient will need to have a clear performance advantage over existing alternatives. In this context, it is important to bear in mind that cost analysis is an additional element that needs to be incorporated into the holistic approach to the development of low-fat foods already advocated from a technical point of view. A complication here is that direct price comparison between different fat mimetics does not necessarily reflect real cost differentials since, more often than not, each fat mimetic will require different adjustments in the type and concentration of other ingredients in the formulation in order to produce an end product of comparable quality. This issue is of particular importance when there are significant differences in the chemical composition of the fat mimetics being compared, since they would be more likely to have an impact not only on textural characteristics, but also on flavor and the overall flavor release mechanism, as discussed in Chapter 4. Finally, the retail price of a low-fat product compared with the standard product will have an effect on relative sales volumes. In this context, it is worth noting that there are many low-fat variants currently on the market priced at the same level or even lower than the equivalent full-fat products (Dibb, 1994). This trend can be seen as a positive initiative of food manufacturers and retailers to achieve a wider public appeal and increased sales of low-fat products, and further emphasizes the need for a macromarketing approach to popularize products that are nutritionally more beneficial.

REFERENCES Anon., Taking the non-fat option, Food Man., August 17, 1990. Anon., Quest for fat substututes taking many routes, Inform, 2 (2), 115, 1991a. Anon., Ault Foods develops fat replacement, Food Drink Daily, August 30, 1, 1991b. Anon., Fat substitutes: Finding method in the madness, Prepared Foods, 161 (13), 21, 1992. Anon., Pfizer introduces Dairy-Lo, Confect. Prod., 59 (7), 538, 1993. Anon., Profiling fat functionality, Source, No. 13, 6, 1994. Anon., Olestra gets a second patent extension, Inform, 6 (4), 412, 1995. Asher, Y. J., Mollard, M. A., Thomson, S., Maurice, T. J. and Caldwell, K. B., Whey protein product: method for its production and use thereof in foods, International patent appl. WO 92/20239, 1992. Ashwell, M., Diet and Heart Disease — A Round Table of Factors, British Nutrition Foundation, London, 1993. Asp, N.-G., Björck, I. and Nyman, M., Physiological effects of cereal dietary fibre, Carbohydr. Polym., 21, 183, 1993.

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Bavington, A. K., Clegg, S. M. and Jones, S. A., Physical and sensory characteristics of low-fat spreads, Leatherhead Food R. A. Res. Rep. No. 695, 1992. Bowes, S. A., Fat substitutes, Third ed., Food Focus, No. 16, Leatherhead Food Research Association, November, 1993. Buss, D., Trimming the fat from fat replacer expectation, Food Process., 54, (10), 44, 1993. Department of Health and Social Security, Diet and Cardiovascular Disease. Committee on Medical Aspects of Food Policy, HMSO, London, 1984. Department of Health, Dietary Reference Values for Food Energy and Nutrients for the United Kingdom, Report of the Panel on Dietary Reference Values, Committee on Medical Aspects of Food Policy, HMSO, London, 1991. Department of Health, The Health of the Nation: A Strategy for Health in England, HMSO, London, 1992. Dibb, S., Low-fat foods, Living Earth and the Food Magazine, No. 184/Issue 27, 3, 11, 1994. Duxbury, D. D., Oatrim: Fat reducer, cholesterol fighter, Food Proc., 51 (8), 48, 1990. Dyerberg, J. and Bang, H. O., Haemostatic function and platelet polyunsaturated fatty acids in Eskimos, Lancet, 2, 433, 1979. Dyerberg, J., Bang, H. O., Stoffersent, E., Moncada, S., and Vane, J. R., Eicopentoenoic acid and prevention of thrombosis and atherosclerosis? Lancet, 2, 117, 1978. Dziezak, J. D., Fats, oils and fat substitutes, Food Technol., 43 (7), 65, 1989. Franks, F., Water activity: a credible measure of food safety and quality? Trends Food Sci. Technol., March, 68, 1991. Glicksman, M., Hydrocolloids and the search for the “oily grail,” Food Technol., 5 (10), 94, 1991. Grundy, S. M., Lipids and cardiovascular disease, in Nutrition and Disease Update. Heart Disease, Kritchersky, D. and Carroll, K. K., Eds., AOCS Press, Champaign, Illinois, 1994, 211. Inglett, G. E. and Grisamore, S. B., Maltodextrin fat substitute lowers cholesterol, Food Technol., 45 (6), 104, 1991. International Commission on Microbiological Specifications for Foods, pH and acidity, in Microbial Ecology of Foods, Vol 1: Factors Affecting Life and Death of Microorganisms, Academic Press, New York, 1980a, 92. International Commission on Microbiological Specifications for Foods, Organic acids, in Microbial Ecology of Foods, Vol 1: Factors Affecting Life and Death of Microorganisms, Academic Press, New York, 1980b, 126. Jamas, S., Easson, D. D., Jr., and Bistrian, B. R., Glucan dietary additives, U.S. Patent 388,572, 1990. Kritchersky, D., Dietary fiber and cardiovascular disease, in Nutrition and Disease Update. Heart Disease, Kritchesky, D. and Carroll, K. K., Eds., AOCS Press, Champaign, Illinois, 1994, 189. Latta, S., Alternative fats, fat substitutes, Inform, 1 (4), 258, 1990. Mattson, F. H. and Volpenheim, R. A., Low calorie fat-containing food composition, U.S. Patent 3,600,186, 1971. Megremis, C. J., Medium-chain triglycerides: a nonconventional fat, Food Technol., 45 (2), 108, 1991. Mela, D. J. and Marshall, R. J., Sensory properties and perceptions of fat, in Dietary Fats — Determinants of Preference, Selection and Consumption, Mela, D.J., Ed., Elsevier Applied Science, London, 1992, 43. Mensink, R. P. and Katan, M. B., Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects, N. Engl. J. Med., 323, 439, 1990. Ministry of Agriculture Fisheries and Food, The Dietary and Nutritional Survey of British Adults — Further Analysis, HMSO, London, 1994a. Ministry of Agriculture Fisheries and Food, National Food Survey 1993, HMSO, London, 1994b. Muyldermans, G., New gelatin-based fat replacers: Slimgel, Food Ingredients Europe: Conf. Proc., Dusseldorf, Nov. 1992, 1993, 178. NACNE, A discussion paper on proposals for nutritional guidelines for health education in Britain, prepared for the National Advisory Committee on Nutrition Education by an ad hoc working party under the Chairmanship of Professor W. P. T. James, Health Education Council, London, 1983. NAS, Diet and Health: Implications for Reducing Chronic Disease Risk, National Academy of Sciences, National Research Council, Food and Nutrition Board, National Academy Press, Washington, D.C., 1989. Perales, I. and Garcia, M. I., The influence of pH and temperature on the behaviour of Salmonella enteritidis phage type 4 in home-made mayonnaise, Lett. Appl. Microbiol., 10, 19, 1990.

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Perez, J., Tello, O., Mata, M. and Fuente, J., Foodborne infections and intoxications — outbreaks evolution in Spain, 1976–1984, Proc. 2nd. World Congress on Foodborne Infections and Intoxications, Berlin, FRG, 1986, 104. Peters, J. C., Holcombe, B. N., Hiller, L. K. and Webb, D. R., Caprenin 3. Absorption and caloric value in adult humans, J. Am. College Toxicol., 10 (3), 357, 1991. Przybyla, A. E., Fats and oils, Food Eng., 62 (11), 99, 1990. Pszczola, D. E., Carbohydrate-based ingredients performs like a fat for use in a variety of food applications, Food Technol., 45 (8), 262, 1991. Richardson, D. P., The food industry response to the Health of the Nation White Paper, Br. Food J., 97, No. 2, 3, 1995. Richter, M., Schierbaum, F., Augustat, S. and Knock, K.-D., Process for the production of starch hydrolysis products, British Patent 1,423,780, 1973. Roberfroid, M., A functional food — chicory fructo-oligosaccharides: A colonic food with prebiotic activity, The World of Ingredients, March/April, 42, 1995. Sanders, T. A. B., Dietary Fat — weighing up the pros and cons, Nutr. Food Sci., No. 5, Sept./Oct., 9, 1994. Singer, N. S., Yamamato, S. and Latella, J., Protein product base, U.S. Patent 4,734,287, 1988. Slade, L. and Levine, H., Beyond water activity: Recent advances based on an alternative approach to the assessment of food quality and safety, CRC Crit. Rev. Food Sci. Nutr., 30, 115, 1991. Smith, R. E., Finley, J. W. and Leveille, G. A., Overview of Salatrim, a family of low-calorie fats, J. Agric. Food Chem., 42, 432, 1994. Stark A. and Madar Z., Dietary fiber, in Functional Foods, Goldberg, I., Ed., Chapman and Hall, New York, 1994, 183. Thayer, A. M., Food additives, Chem. Eng. News, 70 (24), 26, 1992. USDA/USDHHS, Nutrition and Your Health: Dietary Guidelines for Americans (Home and Garden Bulletin No. 232) (3rd ed.), U.S. Department of Agriculture and U.S. Department of Health and Human Services, U.S. Government Printing Office, Washington D.C., 1990. USDHHS, The Surgeon General’s Report on Nutrition and Health: DHSS (PHS) Publication No. 88-50215, U.S. Department of Health and Human Services, U.S. Government Printing Office, Washington D.C., 1988. Wahle, K. W. J. and James, W. P. T., Review: Isomeric fatty acids and human health, Eur. J. Clin. Nutr., 47, 828, 1993. Watts, G. F., Lewis, B., Brunt, J. N. H., Lewis, E. S., Cottart, D. J., Smith, L. D. R., Mann, J. I. and Swan, A. V., Effects on coronary artery disease of lipid-lowering diet, or diet plus cholestyramine in the St. Thomas’ Atherosclerosis Regression Study (STARS), Lancet, 339, 563, 1992. Webb, D. R. and Sanders, R. A., Caprenin 1. Digestion, absorption, and rearrangement in thoracic ductcannulated rats, J. Am. College Toxicol., 10 (3), 325, 1991. Willett, W. C., Stampfer, M. J., Manson, J. E., Colditz, G. A., Speizer, F. E., Rosner, B. A., Simpson, L. A. and Hennekens, C. H., Lancet, 341, 581, 1993. Wyeth, L. J. and Kilcast, D., The importance of sensory and nutritional factors in consumer acceptance of reduced-fat foods, Leatherhead Food R. A. Res. Rep. No. 686, 1991.

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Chapter

2

Implications of Fat Reduction in the Diet Debra L. Miller and Barbara J. Rolls CONTENTS 2.1 Introduction 2.2 Background and Significance 2.3 Why Is Fat Overeaten? 2.3.1 Palatability 2.3.2 Development of a Fat Preference 2.3.3 Differences in Fat Preference 2.3.3.1 Gender Differences 2.3.3.2 Obese/Lean Differences 2.3.4 Energy Density 2.3.5 Satiety Value of Fat 2.4 Low-Fat Diet Research 2.4.1 Short-Term Fat Manipulations 2.4.2 Longer-Term Fat Manipulations 2.5 Noncaloric, Synthetic Fat Substitute Research 2.6 Fat Replacers and Fat Preference 39 2.7 Population-Based Studies 2.8 Conclusions References

2.1 INTRODUCTION “Fat-Free,” “Low-Fat,” “Reduced-Fat” — these labels pervade the supermarkets, the media, and even restaurants and are found on a wide range of products. While some individuals may purchase such products because they prefer the taste, it is likely that

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most will do so to bring about improved health and/or body weight changes. The question is then “Will these products be effective in producing the desired results?” The safety of using fat replacers has received much attention, but comparatively few data are available to address the issue of how these products influence human food intake and energy regulation. Until recently there were few studies examining the effects of variations in the level of fat in foods on energy intake and body composition. This was because until the mid-1980s there was relatively little emphasis on the role of dietary fat in obesity and related disease states, and the technology for formulating palatable reduced-fat foods was limited. Hence, we are only beginning to assess the effectiveness of such substances in reducing both dietary fat and energy intake. Because of the paucity of relevant literature, nutrition professionals and the general public alike may make assumptions that the use of fat-replaced products will bring about automatic reductions in the high intake of dietary fat in Western society. However, we know very little about how consumers use fat-replaced foods. Will fat-replaced foods be substituted for higher fat versions of foods? (“I use low-fat mayonnaise instead of regular mayonnaise.”) Will they be used as substitutes for “forbidden foods?” (“I’ll eat fat-free potato chips, but not regular potato chips.”) Will they be used as a license to increase intake of other types of foods? (“If I use the fat-free salad dressing, I can have a piece of cheesecake for dessert.”) There is also considerable debate in the scientific community regarding whether the overconsumption of dietary fat alone leads to negative health outcomes, or if it is the resultant increase in overall energy intake due to the overconsumption of dietary fat that contributes to these outcomes. In many cases, the trickle down message the general public has received is “I can eat as much food as I want as long as it is low in fat or fat-free.” This chapter examines these questions and the existing scientific literature regarding low-fat/fat-replaced foods and diets to determine the efficacy of using fat replacers as a strategy to reduce intake of dietary fat and total energy.

2.2 BACKGROUND AND SIGNIFICANCE In Western societies, high consumption of dietary fat has been linked to obesity, coronary artery disease, and certain types of cancer, and it is regarded as the top dietary problem in America (Drewnowski, 1990). Currently, dietary fat comprises nearly 36% of the energy content of the American diet. The guidelines of a number of health organizations recommend that no more than 30% of daily energy be derived from dietary fat in order to reduce the incidence of related morbidity and mortality (National Resource Council, 1989; U.S. Department of Health and Human Services, 1989). An obvious method to decrease the percentage of energy from fat is to substitute lowfat foods for high-fat foods. However, it is difficult for many people to limit their food choices to the low-fat varieties. Controlled laboratory-based experiments indicate that high-fat foods are overeaten because they are highly palatable. When a considerable amount of fat is removed from the diet, the diet is often bland and monotonous, and even those whose health status is dependent upon reducing their fat intake, such as cardiac patients, find it difficult to maintain long-term compliance (Drewnowski, 1990). Recent advancements in food technology, particularly the development of fat replacers, may offer one way of reducing fat and energy consumption while satisfying the preference for a high-fat diet. The advent of highly palatable reduced-fat or fat-free foods offers consumers choices that were not previously available, but because there have been few controlled studies of how these products are used by consumers, questions remain about their efficacy in reducing dietary fat intake.

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Several key points to consider when regarding products made with fat replacers include: 1. Why do many people eat more dietary fat than is recommended (30% of total energy) and will fat replacers satisfy people’s desire to consume fatty foods? 2. Will eating foods that use fat replacers aid in lowering the amount of fat consumed? That is, will the fat and/or energy reduction be compensated for in subsequent intakes? 3. How will these products be used by the consumer (in place of regularly eaten foods, as a license to eat previously “forbidden foods,” or to allow for increased consumption of other foods)? 4. Will individuals learn with repeated experiences that reduced-fat and reduced-energy foods do not satisfy hunger as well as their high-fat counterparts? If such learning takes place, will this reduce palatability so that such products are no longer included in the diet?

2.3 WHY IS FAT OVEREATEN? 2.3.1 PALATABILITY Fats are responsible for the texture, flavor, and odor of many foods. However, dietary fat is rarely consumed in pure form, instead, it is consumed as part of a complex food containing other nutrients (protein and carbohydrate) in varying degrees. This makes it difficult to assess a fat-specific preference in foods. Fats contribute to many different sensory properties of food. The first sensory response to fats is olfactory, through perception of volatile fat-soluble molecules that impart the characteristic flavor or aroma to many foods (Drewnowski, 1990). Secondly, fats contribute to the oral sensation by endowing foods with certain textures (such as being hard or soft, oily or juicy, elastic or flaky, heavy, viscous, or smooth) and “mouthfeel,” which is described by Drewnowski (1990) as its “distribution in the oral cavity during chewing and swallowing.” These textural and mouthfeel characteristics enhance the richness of food flavor, and strongly influence the palatability of the diet (Drewnowski, 1987; Mela, 1990). The desirable characteristics that fats endow to food have been identified by various studies (Drewnowski et al., 1985; Drewnowski and Greenwood, 1983; Drewnowski et al., 1989). Sensory panels have determined preferences for sweet/fat mixtures such as milk shakes, cake frostings, and ice cream (Drewnowski, 1987; Drewnowski et al., 1985; Drewnowski and Greenwood, 1983). In one study, sweetened skim milk and unsweetened cream were rated relatively low, but the combination of sugar and fat in sweetened heavy cream was highly appealing (Drewnowski et al., 1985). Of course, it is fat, not sugar, that provides the majority of the energy in such a mixture and in other sweet, fat-rich desserts. In a survey of U.S. military personnel (Meiselman and Waterman, 1985), it was found that the most preferred foods were steak, French fries, and milk — which are high in dietary fat. In contrast, some of the least preferred foods in this survey were vegetables, skim milk, diet soda, and cottage cheese, which are very low in fat (Meiselman and Waterman, 1985). Surveys of attitudes toward dietary fat (Shepherd and Stockley, 1985; Shepherd and Stockley, 1987) indicate that highly preferred foods often have a high-fat content. In these studies, taste is the primary reason given for the selection of a particular food. Since fat imparts characteristics associated with high palatability, high-fat foods are often chosen. 2.3.2 DEVELOPMENT OF A FAT PREFERENCE Is our preference for high-fat foods innate or learned? Just as the preference for sweet taste, which is thought to be innate, is useful in identifying foods that are safe to eat, an

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innate fat preference could have been adaptive for survival by encouraging consumption of a dense, easily stored energy source for periods of scarcity. However, if humans did acquire adaptations that encouraged fat consumption, these adaptations have become maladaptive in today’s society, which is characterized by an overabundance of foods (Birch, 1992). There is some evidence that children display preferences for high-fat foods (Birch, 1992; Johnson et al., 1991; Kern et al., 1993). In experiments with high- and low-fat yogurt shakes, Johnson and colleagues (1991) found that preferences for initially novel foods high in fat content can be learned, and that conditioning of these preferences is the result of the postingestive consequences of consumption. Rozin and Zellner (1985) argue that this type of Pavlovian or associative conditioning is central to the acquisition of food preferences. Because high-fat foods are palatable and satisfying, which are positive consequences of consumption, children learn to like these foods (Birch, 1992). Such foods are also often used as treats or rewards for children, which may enhance this preference (Birch, 1992). The animal literature suggests that fat may be preferred at an early age in rats (Ackroff et al., 1990; Sclafani, 1990). Ackroff and colleagues (1990) measured fat appetite in infant rats. In this study, which used intake as an index of preference, 12 to 15 day old pups consumed nearly as much oil emulsion solution as a dilute sucrose solution (0.03 M) and only slightly less than a milk formulation similar to rat’s milk; they concluded that the taste for fat was as pleasant to the pups as sweet solutions and mother’s milk. However, in humans, there is no evidence to support the hypothesis that there is an innate, unlearned preference for fat, and the possibility of such seems unlikely because the form and function of fat is not unitary across food systems (Drewnowski, 1987). Furthermore, Drewnowski and colleagues (1991) have shown that there is no relationship between taste preferences for high-fat foods and early age (<10 years) of onset of obesity (thought to be a measure of familial risk); they concluded that environmental as opposed to familial factors may be more immediate determinants of taste preferences and food choice. 2.3.3 DIFFERENCES IN FAT PREFERENCE 2.3.3.1 Gender Differences Just as “Jack Sprat would eat no fat and his wife would eat no lean,” differences in fat preferences between men and women have been noted anecdotally. Recent epidemiological surveys have provided evidence that there are indeed gender differences in regard to fat preferences. Although both men and women seem to find high-fat foods highly palatable, men seem to derive the bulk of their dietary fat from red meat, whereas women derive dietary fats mainly from margarine, whole milk, shortening, and mayonnaise (Block et al., 1985). Women are also more likely than men to express preferences for sweet/fat desserts like cake and ice cream (Block et al., 1985). These gender differences persist among obese individuals as well. Drewnowski and colleagues (1992) surveyed the favorite foods of obese men and women and found that obese men listed predominantly fat-protein sources (meat dishes) among their favorite foods while obese women listed more carbohydrate/fat sources and more sweet foods (doughnuts, cookies, cake, and chocolate). 2.3.3.2 Obese/Lean Differences It has been proposed that obese persons may have an enhanced preference for high-fat foods leading to overconsumption of energy dense foods. In sensory tests, obese individuals have shown a preference for higher levels of fat in foods than lean individuals

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(Drewnowski, 1987). Several investigators have found that body weight was related to preferences for fat. In 1985, Drewnowski and colleagues found that obese and formerly obese individuals preferred higher levels of fat in mixtures of dairy products and sugar than did lean individuals. However, in a 1991 study, Drewnowski found that only a subset of obese, those with a history of large weight fluctuations, showed an enhanced fat preference. Mela and Sacchetti (1991) found a positive relationship between sensory preferences for fat in a variety of foods and percent body fat in normal weight subjects. It has been shown that as body fat increased, the percent of energy derived from fat increased (Miller et al., 1990; Strain et al., 1992), and, in a 3-year longitudinal study (Klesges et al., 1992), high weight gain was associated with high fat intake in both men and women. This work taken together indicates that enhanced preferences for fat could be important in the development and maintenance of obesity; however, no controlled, laboratory-based experiment has looked at this issue directly. Additional research is needed to understand how the sensory qualities of fat and individual differences in preferences for dietary fat influence human food intake and body composition. 2.3.4 ENERGY DENSITY Dietary fat provides approximately 9 kcal/g compared with 4 kcal/g for carbohydrate or protein (Burton and Foster, 1991). The relatively high energy density of fat could be a factor in its overconsumption if there is a tendency to eat a certain volume or weight of food. For example, 100 g of potato chips (which are typically 60% energy from fat) has 538 kcal, while an equal amount of pretzels (which are typically about 8% energy from fat or less) has only 375 kcal. Several studies which have varied the fat content of foods (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991; Tremblay et al., 1991) have found that subjects consumed a nearly equal volume of food despite differences in energy density. Thus, the more energy-dense, high-fat diets were associated with increased daily energy intakes when compared to the low-fat diets. In some of the studies which have manipulated dietary fat (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991), subjects were given access only to foods within a specified (high or low) fat content, i.e., energy density. The results from these studies showed reduced energy intake on low-energy-density diets. However, in such situations, there appeared to be a tendency to eat a relatively constant amount of food, and it is possible that if the experiments lasted longer, the amounts of the low-fat foods eaten would gradually increase so that daily energy intake would be maintained. These studies will be discussed in more detail in following sections regarding low-fat diet research. 2.3.5 SATIETY VALUE OF FAT Dietary fat may be overconsumed because it does not satisfy hunger as well as other nutrients. This hypothesis is related to the physiological consequences of ingested fat such as stomach distention, stomach emptying, nutrient absorption, hormonal release, oxidation of nutrients, and so on. Several sources suggest that fat and carbohydrate have very different postingestive consequences. Data from experiments measuring postabsorbtive metabolism suggest that dietary fat is not metabolized as rapidly as carbohydrate and protein (Schutz et al., 1989). Ingested carbohydrates produce rapid rises in blood glucose (Van Amelsvoort et al., 1989), while fats often depress blood glucose (McHugh et al., 1975). Thus, depending on the accuracy of the “glucostatic theory,” which suggests that the sensation of hunger is maintained until blood glucose levels reach adequate levels, it is possible that carbohydrates produce more rapid satiety than fats. Conversely, there are factors associated with fat intake that may influence satiety as well. One of these factors is the release of “satiety hormones.”

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Cholecystokinin is one such putative satiety hormone (Smith and Gibbs, 1988) that is released when some types of fat enter the intestine (Canton, 1992). Thus, the ingestion of fat, in theory, could lead to early satiety as well. On the basis of these differing physiological effects, it is difficult to make any definitive statements regarding the satiety value of fat vs. carbohydrate. A recent paper by Rolls and Hammer (1995) reviewed various studies that utilized a preloading paradigm (giving fixed amounts of the macronutrients and determining the effects on subsequent hunger, satiety and food intake) to detect a difference in the satiety value of fat vs. carbohydrate. In this review, they concluded that carbohydrate may have a greater satiety value than fat in individuals with certain subject characteristics (e.g., obese and those concerned with their body weight). However, overall there is little evidence that carbohydrate has a greater satiety value than fat, and it remains to be determined whether the overconsumption of fat and energy is due to a physiological insensitivity to the amount of fat in foods.

2.4 LOW-FAT DIET RESEARCH Much of the research regarding dietary fat intake has predated the development of many fat replacers. This section reviews research that has manipulated dietary fat intake. Some studies have used foods naturally low in fat (fruits, vegetables, and grains) to reduce the fat content of the diet. Others have used certain fat-replaced products that were available at the time of study or a combination of naturally low-fat foods and fat-replaced foods. The following studies will be used to illustrate the effects of reducing the fat content of the diet on both energy and fat intake. 2.4.1 SHORT-TERM FAT MANIPULATIONS Several studies have investigated the effects of manipulating the fat content in certain meals on energy intake on a short-term basis (≤ 5 days). Caputo and Mattes (1992) manipulated the energy and fat content of a midday meal for 5 days by using traditional low-fat foods and some commercially available reduced-fat foods. They found that both males and females compensated for energy dilutions in their diet; however, compensation for a surfeit of energy was weaker, especially when the additional energy was derived from dietary fat. Firm conclusions cannot be drawn from this study because the data for fat intake were obtained via diet records, and such data should be interpreted cautiously due to the potential errors and biases in using self-reported measures. However, similar results were found in a well-controlled residential laboratory study (Foltin et al., 1988) that manipulated the carbohydrate and fat content in certain meals. In this study, subjects (lean males) compensated well and quickly for the caloric dilution, but when the energy level was again raised to baseline levels subjects did not compensate and overate. In a subsequent residential study (Foltin et al., 1990) that manipulated the fat and carbohydrate content of a lunch meal using four conditions (high-fat, high-carbohydrate, lowfat, low-carbohydrate; with 3 days per condition), energy compensation was observed regardless of macronutrient composition (mean daily energy intakes: 2824, 2988, 2700, and 2890 kcal, respectively). However, energy intake from dietary fat was fairly constant in all conditions except the high-fat condition which was significantly greater than the other three conditions. The results of these studies indicate that when there is a decrease in the fat content (and thus the energy content) of the diet, the energy reduction may be compensated for in subsequent meals or snacks, but the fat reduction per se may not. Furthermore, there is some evidence that when additional fat is included in the diet, it is unlikely that a spontaneous reduction in energy and fat intake will occur to compensate

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for this surfeit (Caputo and Mattes, 1992; Foltin et al., 1988). These findings are, however, dependent on the magnitude of the manipulation and the characteristics of the subjects being tested (e.g., lean/obese, restrained [concerned about body weight]/unrestrained [not concerned about body weight]). 2.4.2 LONGER-TERM FAT MANIPULATIONS The studies mentioned above (Caputo and Mattes, 1992; Foltin et al., 1988; Foltin et al., 1990) manipulated fat intake within specific meals or over the course of a day. These types of interventions provide useful information about short-term regulation of fat and energy intake when dilutions and surfeits are introduced into the diet; however, they provide no information about long-term regulation or the ability to maintain compliance to a low-fat diet. A few naturalistic studies (Schlundt et al., 1993; Mattes, 1993; Gatenby et al., 1993; Sheppard et al., 1991) have been designed to reduce the overall intake of dietary fat in certain groups over longer periods of time. These studies used various strategies (nutritional counseling, behavioral therapy, or financial incentives) to aid subjects in reducing their dietary fat consumption. Results of these studies generally showed that the intervention groups consumed less dietary fat than control groups. Intervention periods in these studies ranged in duration from 12 to 20 weeks, which indicates that compliance to a low-fat diet can be maintained over a moderate amount of time; however, there are few data regarding the long-term compliance to a low-fat diet. Sheppard and colleagues (1991) followed 303 women participating in the Women’s Health Trial for one and two years. These women either received intensive instruction in maintaining a low-fat diet (reducing cooking fats, substituting low- or no-fat variants of high-fat foods and increasing traditional low-fat foods in the diet) or they were part of the control group. After 1 year, the intervention group had reduced their dietary fat intake by 45% of their baseline intake and energy intake by 59%. Most of the reductions occurred within the first 6 months of the intervention and were maintained at the 1- and 2-year follow-ups. Results of naturalistic studies such as these (Schlundt et al., 1993; Mattes, 1993; Gatenby et al., 1993; Sheppard et al., 1991) are often used as the basis for advocating low-fat diets and that compliance to low-fat diets can be maintained over time. However, although these studies may have some external validity, they relied heavily on self-report and diet records as a source of data for fat intake, and should therefore be interpreted cautiously. In this review, we will next focus on laboratory-based experiments that provide more accurate intake measurements and stringent controls over the experimental setting. Three controlled, laboratory studies (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991) have investigated the effects of high- and low-fat diets on energy intake and body weight over varying periods of time. In 1983, Duncan and colleagues fed lean and obese subjects a low-energy density diet comprised of traditionally low-fat foods (fruits, vegetables, and grains) and a high energy density diet for 5 d (0.7 kcal/g vs. 1.5 kcal/g). Subjects could eat the foods ad libitum. The results showed that both obese and nonobese groups significantly reduced their energy consumption on the low-energy diet. Nearly twice as many calories were consumed during the high-energy density diet compared to the low-energy density diet (3000 vs. 1570 kcal/d). No data were supplied regarding weight change during the test periods. Two other studies which were conducted at Cornell (Lissner et al., 1987; Kendall et al., 1991) are often cited in both scientific and popular literature as proof that ad libitum consumption of low-fat foods can reduce fat intake and produce weight loss. The low-fat diets in these studies included currently available fat-replaced foods, primarily margarines, salad dressings, and mayonnaise as well as traditionally low-fat foods. The first of these studies, conducted by Lissner and colleagues in 1987, provided all food

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(meals and snacks) to 24 women who were divided into groups of <101% ideal body weight (IBW) and >101% IBW. Subjects were each fed 3 diets: low-fat 15 to 20%, medium-fat 30 to 35%, and high-fat 45 to 50% of energy. Subjects could eat the foods ad libitum. Each diet was fed for 14 d with a 7-d washout between the test periods. The results showed that energy consumption was positively correlated with the level of dietary fat, with the total daily energy consumed on the low-fat diet being 2087, the mediumfat diet 2352, and the high-fat diet 2614 kcal. Over the two-week periods, the diets did not produce any statistically significant weight changes. The second Cornell study, conducted by Kendall and colleagues (1991), was similar but extended the intervention period to 11 weeks. It is unclear whether lean or obese women were studied; although a mean subject height was reported, there was no mean weight reported. It is noted that individuals <101% of ideal body weight (according to Metropolitan Life standards) were excluded from the study. This study examined two diets that differed in fat content: one diet was comprised of 20 to 25% fat (low-fat) and the other diet was 35 to 40% fat (control). Again, the women were given free access to foods. Results showed that the subjects consumed an average of 286 kcal/d less on the low-fat diet. The subjects in this experiment, in contrast to the Lissner and colleagues study (1987), did lose weight. Weight loss was significantly greater on the low-fat diet; however, subjects lost weight on both diets (low-fat: –2.54 kg and control: –1.26 kg). There were no reasons given by the authors for the weight loss on the control diet. A recent animal study by Harris (1994), examined the effect of three groups of 20 female Sprague-Dawley rats (60 rats in total) chronically fed either a high-fat diet (45% energy from fat) or a low-fat diet (25% energy from fat) containing either no added fat replacer (control diet) or the maltodextrin Paselli, a starch-derived fat mimetic produced by Avebe and described in more detail in Chapter 6B. All three diets in this study had different textures. Rats were fed the control diet for 10 d, and were then divided into three groups, receiving one of the three diets for 42 d. Preference tests for the three diets were assessed before and after the 42-d period. Results showed that all but two of the rats preferred the fat mimetic diet over the high-fat and control diets and food intake was the greatest in the group fed the fat mimetic diet (741 g/58d = control, 736 g/58d = high-fat, 900 g/58d = fat mimetic). However, energy intake was greatest in the group fed the high-fat diet (3250 kcal/58d = control, 3871 kcal/58d = high-fat, 3585 kcal/58d = fat mimetic). The higher energy intakes of the high-fat and mimetic-fed animals resulted in greater weight gain during the experimental period and a heavier carcass weight at the end of the experiment, compared with control rats, largely due to an increase in carcass fat. Harris (1994) concluded from these data that the inclusion of highly preferred, fatmodified foods in the diet may result in a reduction in fat intake, but including such foods may not aid in limiting energy intake. The evidence from human studies presented here indicates that low-fat diets are potentially useful for reducing both the total energy intake and the amount of fat consumed. However, although these early results have some validity, their interpretation is often oversimplified. When reviewing research on the effects of low-fat diets, it is important to recognize that the methods available have limitations which may influence outcome. The three laboratory-based studies reviewed above (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991) have allowed subjects to consume food ad libitum in their dietary interventions; however, this access was limited to the particular fat level that was under study. In other words, during a low-fat condition, the subjects could only choose from low-fat foods, and in the high-fat condition, only high-fat choices were available. And, although the subjects rated the diets equally palatable, this does not mean that, given a choice, they would voluntarily eat the low-fat foods. Thus, it is difficult to

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determine if these findings in the human studies would be applicable to free-living individuals. And, as shown in the recent animal study (Harris, 1994), even when restricted to a highly palatable low-fat diet, overall energy intake may not be reduced and may even be increased. Also, these initial studies did not provide subjects with any information (nutritional or otherwise) about the foods that they were eating. Food products are labeled with claims such as “lite,” “reduced-fat,” “fat-free” that send powerful messages to the consumer. The results of the low-fat diet studies cited above (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991) might be different for individuals who knowingly choose to substitute a low-fat food for a high-fat food. Shide and Rolls (1995) have examined the impact of such information on subsequent food intake. This study, using yogurt preloads, found that intake at a self-selection meal was higher following preloads labeled “low-fat” than following equicaloric preloads labeled “high-fat” indicating that information about fat content can influence food intake regardless of the actual energy content of the food. It seems that cognitive processes can override or interact with physiological processes in regard to food intake and, therefore, play an important role in energy balance. Cognitive processes may also be involved in the regulation of food intake by controlling the amount of food consumed by its weight or volume rather than by its energy content. In other words, individuals may control how much they eat by setting a “standard portion size” of food consumed rather than a “standard energy amount.” As discussed previously, it is likely that it is the energy density of the diets provided in these low-fat diet studies (Duncan et al., 1983; Lissner et al., 1987; Kendall et al., 1991) and not some physiological satiety mechanism that at least partially accounts for the differences in the amount of energy consumed. In each of these studies, subjects ate similar gram weights of food on both low-fat and high-fat diets. It is likely that subjects are eating a “standard” weight or volume and not responding to the covert energy manipulation. Thus, a diet of low-energy-density consumed in equal amounts as a higher-density diet would provide less energy. It may be that fat-replaced foods may have their greatest impact on fat and energy intake by reducing the energy density of the foods we consume. By replacing a wide-range of high-fat foods with low- or no-fat variations of those foods, the net result could be to reduce the energy density of the diet and, in turn, the amount of overall energy consumed. If fat-replaced foods are consumed in much greater quantities than their high-fat counterparts, this net energy reduction will be nullified. The hypothesis that one can consume an unrestricted amount of low- or no-fat food and still expect to bring about desirable dietary change and/or weight loss or maintenance is not supported by animal or human literature. Sclafani and colleagues (1993) fed Sprague-Dawley rats high-fat (41%) or no-fat (0%) cakes in addition to chow for 30 d. The test foods were a no-fat pound cake and a high-fat pound cake both marketed by Entenmann’s. The no-fat pound cake was prepared with non-fat milk and egg whites, and used modified cornstarch, xanthan gum, and guar gum to simulate the orosensory properties of fat. The rats fed high-fat cake and chow consumed more energy (p<0.05) and gained more weight (p<0.05) than did rats fed no-fat cake and chow. The rats fed no-fat cake, however, overate and gained more weight than did the chow-only controls (Figure 2.1). The authors concluded that removing the fat from the cake reduced, but did not eliminate, its obesitypromoting effects, and that low-fat diets have to be consumed in moderation if used for weight loss purposes. To examine the question of whether fat reduction with no other dietary restriction leads to weight loss in humans, Schlundt and colleagues (1993) tested the effects of both

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Figure 2.1 Mean (± SEM) daily caloric intake of rats fed chow only (Control group), chow and high-fat cake (High-fat group), or chow and no-fat cake (No-fat group). Intakes were averaged over 5-day blocks; BL represents 5-day chow baseline period. Top panel: total calories; center panel: calories derived from cake; bottom panel: calories derived from chow. (From Sclafani, A., Weiss, K., Cardieri, C., and Ackroff, K., Obesity Res., 1, 173, 1993. With permission.)

a low-fat ad libitum consumption diet and a low-fat caloric restriction diet on adult men and women who were at least 20% above ideal body weight. They found that subjects on the caloric restriction diet lost significantly more weight and reduced fat intake to a greater extent than those on the ad libitum low-fat consumption diet. Hence, advocating that an individual can eat as much as he/she desires and lose weight as long as the food ©1996 CRC Press LLC

is low in fat content (Kendall et al., 1991) is unwarranted based on these data. For weight loss purposes, energy intake must also be limited. The next question is whether varying the fat content, while keeping energy equal, on an energy-restricted diet is beneficial in regard to weight loss. This question has been addressed in an animal study by Boozer and colleagues (1993). They found that when rats previously fed a high-fat diet (40% of energy) were switched to equicaloric diets (75% of their previous ad libitum intake) that varied in fat content (12, 28, or 45% fat), rats fed the 12% fat diet lost significantly more body fat than the rats fed the 45% fat diet. These results indicate that an energy-restricted diet produces greater weight loss when it is also low in fat in these experimental animals. Although similar data are not available for humans, if weight loss is a goal, it seems prudent to advise restriction of both dietary fat and overall energy intakes to achieve maximum results. It follows that reduced-fat foods may provide one strategy for weight loss if an individual who is consuming greater than 30% of energy from fat can restrict food choices to those low in fat but not high in energy, while keeping the volume of food consumed constant.

2.5 NONCALORIC, SYNTHETIC FAT SUBSTITUTE RESEARCH Because noncaloric, synthetic fat substitutes have the greatest potential range of applications as fat replacers, it is important to review the current research on the effects of consuming these materials on food intake and body composition. Sucrose polyester or olestra (its generic name) by the Procter and Gamble Co. has recently been approved for use in the U.S. in savory snacks, using the tradename Olean. SPE is a fat-like material consisting of hexa-, hepta-, and octa-esters of sucrose and long-chain fatty acids with physical properties entirely similar to those of conventional dietary fats (Mattson and Volpenhein, 1972a and b). The resulting molecule is too bulky to be hydrolyzed by pancreatic lipases, and consequently it is not taken up by the intestinal mucosa and absorbed (Mattson and Volpenhein, 1972a and b). Because SPE is not absorbed, it passes through the digestive system intact and adds no energy to the diet and is excreted in the feces. Animal studies comparing varied levels of fat and SPE have shown that the higher the percentage of fat in the diet, the greater the fat intake and in some cases, the body weight. Grossman and colleagues (1994), for example, examined the effect of SPE replacement on the body weights of lean and obese Zucker rats. In this study, 8-week old lean and obese animals received either a control diet (15% corn oil) or an SPE diet (5% corn oil and 10% SPE). The obese control-fed animals gained more weight than the animals fed the SPE diet. Lean rats given the fat substitute did not have significantly different body weights as compared to the lean controls. The authors concluded that the obese rats could not maintain their higher weights when the fat content of their diet was diluted using SPE. The first controlled study using sucrose polyester in humans was conducted in 1982 by Glueck and colleagues. These authors were investigating the effect of using SPE in hypocaloric diets in obese persons for weight loss purposes. In this study, the effects of SPE and a hypocaloric diet were studied in a counterbalanced, crossover design over two 20-d periods. Subjects also had access to non-SPE modified snacks in the evening, which provided a limited opportunity for subjects to compensate for the calorie/fat dilution. Subjects showed weak compensation for the missing calories resulting in a significant overall reduction in energy intake (p< 0.05) and fat intake (p< 0.05). However, a potential confound exists because subjects were actively trying to lose weight in this study, which may have reduced their likelihood of consuming snacks. Thus, this study does not provide an adequate design to assess energy/fat compensation. ©1996 CRC Press LLC

In 1983, Porikos and colleagues diluted the fat content of the diet of five obese men confined to a metabolic ward for 36 d by replacing fat in margarine and mayonnaise with SPE. Energy intake was measured in three conditions: pre-intervention baseline (days 1 to 9), intervention (days 10 to 28) and post-intervention baseline (days 29 to 36). In the intervention period the manipulation created a 10% reduction of overall energy of the diet. The results showed that subjects increased the amount of food consumed during the SPE period relative to the pre- and post-intervention baselines so that there was no significant effect of diet on energy intake (baseline = 3924 kcal/d and SPE = 3812 kcal/d). Subjects did not selectively ingest more fat but rather increased their intake of all three macronutrients to compensate for the energy dilution due to the addition of the SPE. Rolls and colleagues, in the U.S. (1992), and Burley and Blundell, in the U.K. (1991), ran parallel studies that were the first to focus on the use of olestra in lean individuals. In each trial that investigated a SPE manipulation in a breakfast meal (biscuits/scones and margarine), 24, healthy, lean males participated. Subjects were fed the three breakfasts (control = 765 kcal, 20 g SPE = 582 kcal, and 36 g SPE = 445 kcal) in a counterbalanced, crossover design followed by self-selection lunch and dinner meals. Subjects also recorded any evening snacks to account for 24 h energy intake. Despite differences in the country of the testing, similar results were obtained in both studies. The lean men compensated well for the energy dilution due to SPE replacement (Figure 2.2), but there was very little fat-specific compensation resulting in a significant reduction (p<.0034 and p<0.0066) in fat consumption with 20 and 36 g SPE substitution, respectively, compared to placebo (Rolls et al., 1992).

Figure 2.2 Mean cumulative (bottom to top of bars) energy (kJ) consumed for all subjects under each condition for all meals during which data was collected. , next-day breakfast; , snack; , dinner; , lunch; and , test breakfast. (From Rolls, B.J., Pirraglia, P.A., Jones, M.B., and Peters, J.C., Am. J. Clin. Nutr., 56, 84, 1992. With permission.)

Similar energy compensation was observed with children (Birch et al., 1993). Researchers measured 29 normally developing 2 to 5 year olds during five, 2-d periods over 5 weeks. Approximately 14 g of SPE was substituted for fat (-125 kcal) in the children’s diet over the course of the morning and afternoon. The children compensated for some of the energy dilution by the end of the first day, and by the end of the second day they had compensated for all but 23.9 kcal. Similar to adult men, children did not show macronutrient compensation, but instead the manipulation produced a reduction in the percent of fat consumed without reducing the total energy of the diet through an increase in carbohydrate intake. In other recent studies reported in abstracts, neither complete fat nor energy compensation was found when SPE was incorporated into foods. In one study, the incorporation

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of 55 g of SPE in either meals or snacks across a day was associated with a decrease in fat and energy intake on that day (Cotton et al., 1993). This energy reduction was not fully compensated for the following day either (Cotton et al., 1993). In preliminary work by Hulshof and colleagues (unpublished a and b), incorporation of SPE into croissants and warm meals was followed by incomplete caloric compensation so that daily energy intake was reduced. However, the social setting, which has been shown to have a substantial impact on food intake (Shide and Rolls, 1991), was not controlled in these studies. These findings may be further confounded by methodological issues such as overt weighing of subject’s food and the lack of compliance checks (Hulshof, 1994). Thus, the results are equivocal regarding the efficacy of using foods prepared with SPE to reduce fat and/or energy intake. The existing evidence (derived from relatively few studies that have been conducted and published), suggests that SPE incorporation into foods may aid in reducing the amount of fat consumed. The evidence is, however, less clear regarding its use in reducing total energy intake. Again, it is necessary to note that these studies used covert manipulations; that is, subjects were unaware of the fat manipulation. It is difficult to assess whether or not this will be representative of how individuals will consume such products when provided with information about the product. Clearly, more studies are needed to clarify the effects of fat replacers on energy intake. The variable effects of SPE on energy intake notwithstanding, the availability of palatable low-fat foods is likely to aid in the reduction of fat intake if such items are chosen instead of the full-fat versions of the same foods and if they are eaten in the same quantity. These issues were examined in a study in which 96 habitual potato-chip eaters (lean and obese men and women) ate regular fat potato chips (5.3 kcal/g, 60% energy from fat) and SPE (olestra) chips (2.8 kcal/g, 0% energy from fat) equal in palatability in a counterbalanced study for 10-d periods (Miller et al., 1995). Fifty subjects were given information about the energy and fat content of the chips and 46 were not. The consumption patterns of both types of chips were similar, both showing decreased consumption over time (most likely due to monotony). Furthermore, in unrestrained subjects (lean and obese), there was no significant difference in gram intake between the regular-fat or SPE chips regardless of whether they were aware of the fat and energy content of the chips or not. When restrained individuals (lean and obese) were given information about the chips, they ate significantly more of the SPE chips (+10g/d) than the regular chips, but, because of the considerable fat and energy dilution of the SPE chips, they still consumed less energy and fat in the SPE condition than when consuming the full-fat version of the product. Body weight (lean vs. obese) was a nonsignificant factor. The results of this study suggest that, for some groups, when palatability is maintained, fatreplaced foods may be eaten in a similar manner as their full-fat counterpart even when provided with complete nutritional information. These data also indicate that restrained individuals may increase their consumption of fat-free products when they are aware of the fat content. Because of the complete fat-replacement allowed by the use of SPE in this study, the increased gram consumption of the chips by the restrained subjects did not result in increased fat or energy intakes. However, it is important for such individuals to be aware of the magnitude of the fat and energy dilutions in reduced-fat foods and to be careful not to overconsume such products to such an extent that they minimize or negate the net benefit of using fat-replaced foods.

2.6 FAT REPLACERS AND FAT PREFERENCE There is a concern about the use of fat replacers, especially products like SPE that mimic the properties of fat so closely, that they may reinforce and maintain the preference for

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fatty foods. It may be that the most effective strategy for fat reduction would be to decrease the preference for dietary fat. Mattes (1993) has examined the effects of two different reduced-fat diets, one which allowed the use of fat mimetics (commercially available reduced-fat products such as salad dressings, table spreads, mayonnaise) and one which did not, on the preference for a limited number of high-fat foods. The results indicated that the group which did not experience fatty flavors showed a decrease in the preferred level of fat in test foods, whereas the group using fat replacers showed no such shift. Mattes (1993) concluded that the preference for fat in foods is governed more by exposure to fatty flavors than by the level of fat in foods. Mattes (1993) further suggested that the preference for fat can be lowered and that the best strategy for lowering fat preference is to avoid fat mimetics and fat replacers. However, due to methodological limitations firm conclusions should not be based on this research. First, hedonic measures were obtained on only four foods, and since fat imparts so many sensory properties to foods, it seems unlikely that changes in preferences for fat in one type of food will generalize to other types of foods. Second, because subjects consumed products at home there was little control over the experimental setting. Third, the observed shift in preference did not lead to a reduction in fat intake during a 3-month follow-up period. Finally, data were obtained from diet records with few checks for compliance. Thus, although this hypothesis may have merit, this research needs to be replicated under stricter controls with expanded preference assessments to provide more salient information (Rolls, 1994). However, other long-term studies, such as the Women’s Health Trial (Sheppard et al., 1991), have shown, albeit through self-report and diet records, that reduced-fat foods may be helpful in maintaining compliance on lowfat diets.

2.7 POPULATION-BASED STUDIES As population-based data are not yet available on the impact of low-fat diets, several reports have examined theoretical ways of reducing dietary fat intake to the recommended level of ≤30%. Computer modeling has been used to examine the impact of several general strategies for fat reduction currently available to consumers. These computer modeling studies are based on existing nutrient intake databases and use the documented food and energy intakes of Americans as a reference to examine the effects of manipulating dietary composition. Using this technique, Lyle and colleagues (1992), found that diets can be modified to approach dietary recommendations when fat-free products are substituted for current comparable food choices. Smith-Schneider and colleagues (1992) found that for males, the use of lean meat exchanges alone or in combination with other strategies appeared to be the most effective way to reduce fat intake to recommended levels. Because females have a lower caloric intake, no single strategy was effective in reducing fat intake to ≤30%; however, combinations of strategies, including lean meat exchanges plus use of fat-modified products, proved effective. Finally, using a unique USDA database chronicling energy and macronutrient intakes over an entire year, Beaton and colleagues (1992) examined the effects of using fat replacers on dietary fat intake. Their model predicted that use of low-fat foods or fat replacers could effectively reduce fat consumption, resulting in a net increase in carbohydrate intake. Results from the modeling studies discussed above suggest that a reduction of fat intake can be realistically achieved through use of several different dietary strategies; however, it must be emphasized that these studies are based on hypothetical calculations which as yet have not been tested experimentally.

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2.8 CONCLUSIONS The question that we have examined in this chapter is whether or not reduced-fat foods, especially those utilizing fat replacer technology, are useful in reducing the current trend to overconsume dietary fat in Western societies. This question is difficult to answer considering: (1) only since the 1980s has dietary fat consumption been the focus of nutritional research and (2) many of the advancements in fat replacer technology are even more recent. What we do know is that we consume foods that taste good more readily than those that do not taste good. Therefore, it seems reasonable that the availability of low- or no-fat foods that are also highly palatable may aid in compliance to low-fat diets that were previously bland and unsatisfying. However, although fatreplaced foods may offer new food choices to consumers, it still should not be assumed that the use of fat-replaced foods will bring about significant reduction in fat and energy intakes. The research cited in this chapter regarding currently available fat replacers supports the notion that such products may aid in reducing dietary fat intake but perhaps not overall energy intake. Most studies using traditional low-fat foods and currently available fat-replaced foods have resulted in compensation for energy reductions, but not macronutrient compensation. Results from sucrose polyester studies are equivocal in respect to energy and fat compensation, with some reporting energy compensation while others do not. More tightly controlled, laboratory-based human studies are needed to determine how useful fat replacement will be in reducing overall fat and energy intakes. It is also not known how consumers will use new and existing fat-replaced products. Will they be used as a one-to-one substitution for foods previously high in dietary fat or as license to overeat other rich foods? It may be that the key to the successful use of fat-replaced products lies in the motivation of the consumer to bring about a reduction in his/her intake of dietary fat. Again, more naturalistic studies exploring the potential usage patterns of fat-replaced products are needed to determine their usefulness in bringing about desired dietary changes. Because overall energy intake has been shown to be a factor in weight loss and weight maintenance, the use of fat-replaced foods alone should not be expected to produce spontaneous improvements in body weight management or obesity. Such improvements will still be dependent upon long-term behavioral changes that include not only modifications in fat intake, but also modifications in overall energy intake and increases in energy expenditure. Because fat is the most energy dense macronutrient, substituting low-fat foods can substantially reduce the energy density of the diet provided these foods are also low in energy. If the energy density of the diet is reduced and volume of intake remains constant, reductions in energy intake are likely. These caveats stated, fat-replaced foods could aid motivated individuals to reduce their intake of dietary fat and energy. In this regard, fat replacers may prove to be a useful tool in reducing fat intake, but as with most novel approaches more detailed investigations should be conducted to determine the efficacy of such products in reducing fat intake. Future studies are needed to resolve issues of fat and energy balance using fat-replaced foods, and whether it is the energy density, the fat content, or the total energy of the diet that is critical for the prevention of such disease states as obesity, cardiovascular disease and diabetes. Additionally, longitudinal studies (both in the natural environment and the laboratory) need to be conducted to determine the best strategies for long-term compliance to a low-fat diet.

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REFERENCES Ackroff, K., Vigorito, M., and Sclafani, A., Fat appetite in rats: the response of infant and adult rats to nutritive and non-nutritive oil emulsions, Appetite, 15, 171, 1990. Beaton, G.H., Tarasuk, V., and Anderson, G.H., Estimation of possible impact of non-caloric fat and carbohydrate substitutes on macronutrient intake in the human, Appetite, 19, 87, 1992. Birch, L.L., Children’s preferences for high-fat foods, Nutr. Rev., 50, 249, 1992. Birch, L.L., Johnson, S.J., Jones, M.B., and Peter, J.C., Effects of a nonenergy fat substitute on children’s energy and macronutrient intake, Am. J. Clin. Nutr., 58, 326, 1993. Block, G., Dresser, C.M., Hartman, A.M., and Carroll, M.D., Nutrient sources in the American diet: quantitative data from the NHANES II survey, Am. J. Epidemiol., 122, 27, 1985. Boozer, C., Brasseur, A., and Atkinson, R.L., Dietary fat affects weight loss and adiposity during energy restriction in rats, Am. J. Clin. Nutr., 58, 846, 1993. Burley, V.J. and Blundell, J.E., Evaluation of the action of a non-absorbable fat on appetite and energy intake in lean, healthy males, Int. J. Obesity, 15, suppl. 1, 8, 1991. (Abstract) Burton, B.T. and Foster, W.R., Human Nutrition, 4th ed., McGraw-Hill, New York, 1991, 567. Canton, P., Cholecystokinin in plasma, Digestion, 42, 181, 1992. Caputo, F.A. and Mattes, R.D., Human dietary responses to covert manipulations of energy, fat, and carbohydrate in a midday meal, Am. J. Clin. Nutr., 56, 36, 1992. Cotton, J.R., Burley, V.J., and Blundell, J.E., Effect on appetite of replacing natural fat with sucrose polyester in meals or snacks across one whole day, Int. J. Obesity, 17 suppl. 2, 63, 1993. Drewnowski, A. and Greenwood, M.R.C., Cream and sugar: human preferences for high-fat foods, Physiol. Behav., 30, 629, 1983. Drewnowski, A., Brunzell, J.D., Sande, K., Iverius, P.H., and Greenwood, M.R.C., Sweet tooth reconsidered: taste responsiveness in human obesity, Physiol. Behav., 35, 617, 1985. Drewnowski, A., Fats and food acceptance: sensory, hedonic and attitudinal aspects, in Food Acceptance and Nutrition, J. Solms, D.A. Booth, R.M. Pangborn, et al., Eds. Academic Press, New York, 1987, 189. Drewnowski, A., Kurth, C., Holden-Wiltse, J., and Saari, J., Food preferences in human obesity: carbohydrates vs. fats, Appetite, 18, 207, 1992. Drewnowski, A., Kurth, C.L., and Rahaim, J.E., Taste preferences in human obesity: environmental and familial factors, Am. J. Clin. Nutr., 54, 635, 1991. Drewnowski, A., Shrager, E.E., Lipsky, C., Stellar, E., and Greenwood, M.R.C., Sugar and fat: sensory and hedonic evaluation of liquid and solid foods, Physiol. Behav., 45, 177, 1989. Drewnowski, A., The new fat replacers: a strategy for reducing fat consumption, Postgrad. Med., 87, 111, 1990. Duncan, K.H., Bacon, J.A., and Weinsier, R.L., The effects of high and low energy density diets on satiety, energy intake, and eating time of obese and nonobese subjects, Am. J. Clin. Nutr., 37, 763, 1983. Foltin, R.W., Fischman, M.W., Emurian, C.S., and Rachlinski, J.J., Compensation for caloric dilution in humans given unrestricted access to food in a residential laboratory, Appetite, 10, 13, 1988. Foltin, R.W., Fischman, M.W., Moran, T.H., Rolls, B.J., and Kelly, T.H., Caloric compensation for lunches varying in fat and carbohydrate content by humans in a residential laboratory, Am. J. Clin. Nutr., 52, 969, 1990. Gatenby, S.J., Aaron, J.I., Morton, G., and Mela, D.J., Nutritional implications of reduced-fat foods in free-living consumers, Appetite, 21, 178, 1993. Glueck, C.J., Hastings, M.M., and Allen, C., Sucrose polyester and covert caloric dilution, Am. J. Clin. Nutr., 35, 1352, 1982. Grossman, B.M., Akah, C.C., Hobbs, J.K., and Martin, R.J., Effects of a fat substitute, sucrose polyester, on food intake, body composition, and serum factors in lean and obese Zucker rats, Obesity Res., 2, 271, 1994. Harris, R.B.S., Factors influencing energy intake of rats fed either a high-fat or a fat mimetic diet, Int. J. Obesity, 18, 632, 1994. Hulshof, T., personal communication, February, 1994.

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Hulshof, T., de Graaf, C., and Weststrate, J.A., Short term satiating effect of water, fat and sucrose polyester (SPE) added to warm meals, Unpub. Hulshof, T., de Graaf, C., and Weststrate, J.A., Short-term effects of high-fat and lowfat/high-SPE croissants on appetite and energy intake at three deprivation periods, Physiol. Behav., 57, 377, 1995. Johnson, S.L., McPhee, L., and Birch, L.L., Conditioned preferences: young children prefer flavors associated with high dietary fat, Physiol. Behav., 50, 1245, 1991. Kendall, A., Levitsky, D.A., Strupp, B.J., and Lissner, L., Weight loss on a low-fat diet: consequence of the imprecision of the control of food intake in humans, Am. J. Clin. Nutr., 53, 1124, 1991. Kern, D.L., McPhee, L., Fisher, J., and Birch, L.L., The post-ingestive consequences of fat condition preferences for flavors associated with high dietary fat, Physiol. Behav., 54, 71, 1993. Klesges, R.C., Klesges, L.M., Haddock, C.K., and Eck, L.H., A longitudinal analysis of the impact of dietary intake and physical activity on weight change in adults, Am. J. Clin. Nutr., 55, 818, 1992. Lissner, L., Levitsky, D.A., Strupp, B.J., Kalkwarf, H.J., and Roe, D.A., Dietary fat and the regulation of energy intake in human subjects, Am. J. Clin. Nutr., 46, 886, 1987. Lyle, B.J., McMahon, K.E., and Kreutler, P.A., Assessing the potential dietary impact of replacing dietary fat with other macronutrients, J. Nutr., 122, 211, 1992. Mattes, R.D., Fat preference and adherence to a reduced-fat diet, Am. J. Clin. Nutr., 57, 373, 1993. Mattson, F.H. and Volpenhein, R.A., Hydrolysis of fully esterified alcohols containing from one to eight hydroxy groups by the lipolytic enzymes of rat pancreatic juice, J. Lipid Res., 13, 325, 1972. (a) Mattson, F.H. and Volpenhein, R.A., Rate and extent of absorption of the fatty acids of fully esterified glycerol, erythitol, and sucrose as measured in thoractic duct cannulated rats, J. Nutr., 102, 1177, 1972. (b) McHugh, P.R., Moran, T.H. and Barton, G.N., Satiety: a graded behavioral phenomenon regulating caloric intake, Science, 190, 167, 1975. Meiselman, H.L. and Waterman, D., Food preferences of enlisted personnel in the armed forces, J. Am. Diet. Assoc., 87, 615, 1985. Mela, D.J., The basis of dietary fat preferences, Trends Food Sci. Technol., 1, 71, 1990. Mela, D.J. and Sacchetti, D.A., Sensory preferences for fats: relationships with diet and body composition, Am. J. Clin. Nutr., 53, 908, 1991. Miller, D.L., Hammer, V.A., Shide, D.J, Peters, J.C., and Rolls, B.J. Consumption of fat-free potato chips by obese and restrained males and females, The FASEB J., in press. (Abstract), 1995. Miller, W.C., Lindeman, A.K., Wallace, J. and Niederpruem, M., Diet composition, energy intake, and exercise in relation to body fat in men and women, Am. J. Clin. Nutr., 52, 426, 1990. National Research Council, Diet and Health, National Academy Press, Washington, D.C., 1989. Porikos, K.P., Heshka, S., Xavier Pi-Sunyer, F., and Van Itallie, T.B., Effects of caloric dilution with sucrose polyester on the spontaneous food intake of obese men, Fourth International Congress on Obesity, New York, 79A, 1983. (Abstract) Rolls, B.J., Changing the preference for fat in foods, Nutr. Rev., 52, 21, 1994. Rolls, B.J. and Hammer, V.A., Fat, carbohydrate and the regulation of energy intake, Am. J. Clin. Nutr., 62, 10865, 1995. Rolls, B.J., Pirraglia, P.A., Jones, M.B. and Peters, J.C., Effects of Olestra, a non-caloric fat substitute, on daily energy and fat intake in lean men, Am. J. Clin. Nutr., 56, 84, 1992. Rozin, P. and Zellner, D., The role of Pavlovian conditioning in the acquisition of food likes and dislikes, in Experimental Assessments and Clinical Applications of Conditioned Food Aversions, N. Braveman and P. Bronstein, Eds., The New York Academy Press, New York, 1985, 189. Schlundt, D.G., Hill, J.O., Pope-Cardle, J., Arnold, D., Virts, K.L., and Katahn, M., Randomized evaluation of a low-fat ad libitum carbohydrate diet for weight-reduction, Int. J. Obesity, 17, 632, 1993. Schutz, Y., Flatt, J.P., and Jequier, E., Failure of dietary fat intake to promote fat oxidation: a factor favoring the development of obesity, Am. J. Clin. Nutr., 50, 307, 1989. Sclafani, A., Nutritionally based learned flavor preferences in rats, in Taste Experience and Feeding, Capaldi, E.D. and Powley, T.L., Eds., American Psychological Association, Washington, D.C., 139, 1990. Sclafani, A., Weiss, K., Cardieri, C., and Ackroff, K., Feeding response of rats to no-fat and high-fat cakes, Obesity Res., 1, 173, 1993.

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Shepherd, R. and Stockley, L., Fat consumption and attitudes toward food with a high fat content, Hum. Nutr.: Appl. Nutr., 39A, 431, 1985. Shepherd, R. and Stockley, L., Nutrition knowledge, attitudes and fat consumption, J. Am. Diet. Assoc., 87, 615, 1987. Sheppard, L., Kristal, A.R. and Kushi, L.H., Weight loss in women participating in a randomized trial of low-fat diets, Am. J. Clin. Nutr., 54, 821, 1991. Shide, D.J. and Rolls, B.J., Information about the fat content of preloads influences energy intake in healthy females, J. Am. Diet. Assoc., 95, 993, 1995. Shide, D.J. and Rolls, B.J., Social facilitation of caloric intake in humans by friends but not by strangers. Int. J. Obesity, 15, suppl. 3, 8, 1991. (Abstract) Smith, G.P. and Gibbs, J., The satiating effect of cholecystokinin, in: Control of Appetite, M. Winick, Ed., John Wiley and Sons, New York, 35, 1988. Smith-Schneider, L.M., Sigman-Grant, M.J., and Kris-Etherton, P.M., Dietary Fat Reduction Strategies, J. Am. Diet. Assoc., 87, 615, 1992. Strain, G.W., Hershcopf, R.J., and Zumoff, B., Food intake of very obese persons: Quantitative and qualitative aspects, J. Am. Diet. Assoc., 92, 199, 1992. Tremblay, A., Lavallee, N., Almeras, N., Allard, L., Despres, J., and Bouchard, C., Nutritional determinants of the increase in energy intake associated with a high-fat diet, Am. J. Clin. Nutr., 53, 1134, 1991. U.S. Department of Health and Human Services, Promoting health/preventing disease: year 2000 objectives for the nation, Washington, D.C., Health Services, 1989. Van Amelsvoort, J.M.M., Van Stratum, P., Kraal, H.H., Lussenburg, R.N., and Houtsmiller, U.M.T., Effects of varying the carbohydrate:fat ratio in a hot lunch on post-prandial variables in male volunteers, Brit. J. Nutr., 61, 267, 1989.

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Chapter

3

Market Considerations in Fat Replacement John N. Young CONTENTS 3.1 Introduction 3.2 Consumer Attitudes to Diet and Health 3.3 Market Developments in Reduced-Fat Foods 3.3.1 United Kingdom 3.3.2 Europe 3.3.3 United States 3.4 Market Developments for Fat Replacers 3.5 Conclusions References

3.1 INTRODUCTION There is no doubt that for most developed economies, the consumer’s awareness of the relationship between diet and health has grown considerably in recent years. With fat consumption having been identified by the media, government bodies, and consumers alike as one of the most important factors (if not the most important) contributing to ill health, e.g., heart disease, diabetes, high blood pressure, etc., it comes as no surprise that this has resulted in the growing popularity of reduced-fat foods. This has itself fueled intense research and development activity in the area of fat replacers. While there clearly exists a growing market for fat replacers, initial sales projections for the U.S. and Western Europe appear to have been over-optimistic. After a more detailed examination of the consumer issues that have led to the development of the lowfat food market in the U.S. and Western Europe, and a review of the current status of these markets, various reasons for the comparatively poor market performance of fat replacers to date will be proposed.

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3.2 CONSUMER ATTITUDES TO DIET AND HEALTH In 1993, the Leatherhead Food Research Association (Leatherhead Food RA) in the U.K. undertook a program of qualitative and quantitative consumer research based on group discussions and in-home interviews, respectively, in order to gain a better insight into consumer issues affecting market developments in reduced-fat foods and, as a consequence, the potential market need for fat replacers (Cathro, 1993). In group discussions, respondents agreed that the high fat content of many foods was one of the most important health issues facing them today. Quantitatively, 58% of 509 respondents interviewed in the home rated dietary fat intake as the most important health issue. This was followed by additives (49%) and sugar contained in foods (41%), while salt and fiber were rated as the least important issues, cited by 24 and 16% of respondents, respectively. One of the most worrying aspects about fat intake and cholesterol from a consumer’s point of view was that there were no outward signs of high cholesterol levels and consequently no way of knowing whether an individual was at risk. From a variety of “low and light” sectors, low-fat foods generated highest consumer interest (mean score 3.49 out of a possible 5), followed by low-sugar (Table 3.1). In group discussions, respondents found it difficult to distinguish between cholesterol and fat. On the whole, it seemed that respondents viewed cholesterol more seriously, thinking of it as the substance produced from eating too much fat; cholesterol was most closely associated with blocking arteries and being a contributory factor to heart disease. Table 3.1 Degree of Interest in Low and Light Foods Among 509 Respondents in the U.K. Type of product Low-fat Low-sugar Low-cholesterol Low-salt Low-calorie Low-alcohol

Interest score (mean of 5) 3.49 3.30 3.03 2.94 2.78 2.11

From Cathro, J., Industry and Market Reviews, No. 19, 1993. With permission.

Over half the sample (56%) of the 509 respondents in the U.K. study claimed to be very/quite interested in low-fat foods, and 30% claimed to be very interested. Female respondents showed a higher degree of interest in low-fat foods than their male counterparts; i.e., 62% of female respondents were very/quite interested in low-fat foods compared with only 50% of male respondents. Not surprisingly, interest in low-fat foods varied considerably across the different age groups, and while all respondents were concerned about eating too much fat, actual purchase of low-fat foods was more limited. Interest was lowest for respondents aged 16 to 24 and highest for respondents aged 45 to 64, where 68% of respondents claimed to be very/quite interested in low-fat food. In terms of socioeconomic group, respondents with the highest levels of income (known as AB groups in the U.K.) were most interested in low-fat foods, with 69% stating that they were very/quite interested, compared with only 49% of the respondents in the lowest income brackets (known as DE groups in the U.K.). Regional variations were also apparent, possibly due to regional variations in living standards, with 62% of respondents from the South and Midlands claiming to be very/quite interested in low-fat foods compared with 46% for the North. ©1996 CRC Press LLC

When asked which foods they felt were the main sources of fat in their own personal diets, butter came top, being cited by 40% of respondents (Table 3.2). Interestingly, only one fifth of respondents believed margarine to be a major source of fat in their diet, despite the fact that many margarines have the same fat content as butter. When asked what they felt about the level of fat in their own diet, the consensus of opinions was that fat levels were probably on the high side simply because of the way in which consumers have become used to eating in the U.K. However, over half of the sample (53%) of the 509 interviewed respondents claimed that the levels of fat were probably about right in their own diets while one third claimed that they were a little too high, suggesting a certain degree of complacency among consumers. A small number of respondents who felt that their fat levels were acceptable were those who had had their cholesterol levels measured and had since taken action to reduce fat intake, although even here respondents admitted that they often had difficulty in keeping to such a strict regime. Table 3.2 Main Sources of Fat in Own Diet Cited by 509 Respondents in the U.K. Food product

%

Butter Chocolate Cakes Milk Meat Biscuits Snack foods Margarine

40 30 26 24 22 21 20 19

From Cathro, J., Industry and Market Reviews, No. 19, 1993. With permission.

Respondents in the group discussions cited cutting down on foods such as snacks and chocolate while increasing intake of fresh fruit and vegetables as principal ways of reducing their fat intake. In the quantitative survey, however, cutting down on foods such as cakes and biscuits (cookies) and changing cooking methods were cited by 47 and 31% of the 509 respondents interviewed, respectively (Table 3.3). Of most significance was that nearly one third of the respondents advocated consumption of low-fat foods and low-fat spreads as a means of reducing fat intake while cutting down on dairy products, snacks, and butter/margarine did not feature highly. This finding supports the view that U.K. consumers still have a far from perfect understanding of the relative contributions of different components of the diet to overall fat intake. By contrast, consumers in the U.S. may be more knowledgeable about the main sources of fat in the diet; in one California survey, the overwhelming majority (70%) of respondents identified potato crisps (chips), mayonnaise, ice cream, cheese, and whole milk as important sources of fat in the diet (Bruhn et al., 1992). Furthermore, nationwide surveys in the U.S. have shown that American consumers are eating fewer dairy products and less red meat (Gallup, 1990). Consumers’ views on fat replacers were also explored in the Leatherhead Food RA survey. Some respondents were aware that manufacturers used fat replacers in foods to reduce the fat content; however, few were able to name any such products. Simplesse® produced the highest level of awareness at 5%. The vast majority of respondents (90%) were not aware of any fat replacers and this rose to 98% for respondents aged 65+. A

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Table 3.3 Main Ways to Reduce Fat Consumption Cited by 509 Respondents in the U.K. Activity

%

Cut out cakes and biscuits Change cooking methods Use low-fat foods Use low-fat spreads Cut out chocolate Cut down on red meat Follow healthy diet Cut out chips Eat leaner meat Eat more salads/veg Cut out butter/margarine Cut out snacks/snacking Eat more fruit Use low-fat milk Drink less beer Cut out fried food Cut down on dairy produce

47 31 30 26 4 4 3 3 3 3 2 2 2 2 2 2 2

From Cathro, J., Industry and Market Reviews, No. 19, 1993. With permission.

number of respondents perceived fat replacers as “unnatural” and consequently “unhealthy.” These findings were in stark contrast with reports on the American consumer’s awareness of fat replacers. For example, according to Bruhn and colleagues, 36 and 14% of Californian participants in a survey had heard of Simplesse® and olestra, respectively, although no products containing either of the two ingredients were available on the market at the time of the survey (Bruhn et al., 1992). Regarding usage of low-fat foods, within the quantitative U.K. survey, respondents were given a list of nine food sectors and asked whether they had tried any of the listed products in low-fat form. Table 3.4 shows that low-fat milk and low-fat spreads were the most popular items that had been tried, cited by 83 and 73% of the respondents, respectively. The least popular products were low-fat sausages and low-fat burgers. Low-fat milk was the most popular low-fat product eaten regularly and this was cited by nearly two-thirds (65%) of the sample, while again low-fat sausages and burgers proved to be less popular (Table 3.4). Through the discussion groups, it was possible to identify factors influencing the acceptance and purchase of these products, which is particularly important when considering the future requirement for low-fat foods and fat replacers. On the whole, respondents felt that skimmed and semi-skimmed milk were very healthy products because they were perceived as low-fat and natural. Most respondents now consumed semiskimmed milk on a regular basis and a number had actually grown up with it, many preferring the taste. However, respondents were less enthusiastic about skimmed milk, which they claimed had a particularly watery taste and consistency, although respondents who had been advised to try this by their doctors persevered with it. It was apparent that a wide variety of low-fat spreads had been tried, the prime reason for doing so being health grounds. However, while a number stated that health reasons had prompted initial purchase, such products had now attained the status of a staple purchase, rather than being anything special. Of particular interest was the comment that ©1996 CRC Press LLC

Table 3.4 Low-Fat Products Tried and Eaten Regularly by 509 Respondents in the U.K. Food product Low-fat milk Low-fat spread Very-low-fat yogurt Low-fat salad dressing Low-fat cheese Low-fat crisps (chips) Low-fat cream Low-fat sausage Low-fat burger

Ever tried (% of respondents)

Eaten regularly (% of respondents)

83 73 56 51 47 42 30 28 18

65 55 40 40 19 16 11 9 5

From Cathro, J., Industry and Market Reviews, No. 19, 1993. With permission.

taste was not such a critical factor in acceptance as the product was eaten in combination with other foods, e.g., toast and marmalade. In the discussion groups, consumers were clearly confused about the necessity for very low-fat yogurts, especially as yogurt was perceived as a healthy food anyway. The wide variety of products on the market also added to the confusion. However, despite this confusion, 40% of the 509 interviewed respondents claimed to purchase very lowfat yogurts on a regular basis (Table 3.4). However, it is important to note that with yogurt there is also a question of calorie and sugar content as well as fat levels. While respondents were aware of the high fat content of many snack products, regular purchase of low-fat crisps (chips) was comparatively low at 16%. From the discussion group it could be inferred that the reason for this was their generally unacceptable flavor and texture compared with standard products. Low-fat meat products also came in for a fair amount of criticism on flavor grounds, this being reflected in low purchase frequency, i.e., 9 and 5%, respectively. On exploring the reasons for trying low-fat foods, previous studies by Boyle and colleagues (1991) had indicated that, while health was the prime reason, this tended to be concentrated on those products that were consumed on a regular basis, e.g., milk, spreads, etc. It was not perceived to be important to buy low-fat versions of luxury items, because they were not considered to make much difference to fat intake overall. The 1993 Leatherhead Food RA study, however, suggests that a change in consumer attitudes may have occurred in that consumers considered that if a product existed in low-fat form, it made sense to try it, and, providing the taste was acceptable, it could well replace the standard product. This point is further supported by the dynamic performance of the socalled healthy ice cream category in the U.K. (Table 3.5) and the U.S. in recent years. “Healthy” ice cream is one of the most dynamic sectors of the U.K. low-fat dairy products market, with sales increasing more than threefold between 1990 and 1992. Furthermore, in the Leatherhead study, respondents who had not tried any products in low-fat form (only 42 from a total of 509) were asked why they were not interested in trying them (Table 3.6). Here it is interesting to note that one third of respondents claimed to prefer the taste of the standard product, suggesting that as technological advances give rise to improvements in flavor, more consumers will be tempted to try low-fat versions of foods. When respondents were asked which foods they would like to see made available in low-fat form, chocolate was the most common response, followed by a variety of bakery items. Some respondents did, however, have reservations about the artificial nature of such products. Overall, respondents seemed to be divided into two distinct camps over

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Table 3.5 U.K. “Healthy” Ice Cream Market by Value, 1989-92 Year

Value (£m rsp)

% Growth

1989 1990 1991 1992

2 5 10 23

— +150 +100 +130

From Comber, L.R., Cutler, A.J., and Griffin, P.F., Industry and Market Reviews No. 19, 1993. With permission.

Table 3.6 Reasons for Lack of Interest in Low-Fat Foods Cited by 42 Respondents in the U.K. Reason given

%

Prefer taste of standard product Not trying to lose weight Never thought about it Healthy as I am Too expensive Follow proper diet Low-fat foods are a “con” Am underweight Diabetic

33 29 7 7 5 5 5 2 2

From Cathro, J., Industry and Market Reviews, No. 19, 1993. With permission.

the usefulness of such products. One group claimed that if a low-fat option was provided (and taste was on a par with that of the standard product) then it made sense to try it, since it was likely to be healthier than the standard product and since the consumer was unlikely to be at risk of eating too little fat. Conversely, the second group of respondents claimed that this was actually moving away from a healthy balanced diet and that if traditional treat items started to appear in low-fat form, consumers would simply eat more of them. Respondents agreed that if the move toward low-fat foods incorporated foods traditionally perceived as unhealthy, then consumers as a whole would tend to eat more of the unhealthy items. In this case, the benefits of low-fat foods were not likely to be apparent. Finally, the cost of low-fat foods was also criticized for being unnecessarily high. Clearly, there still exists the view that if a product is promoted as containing less of an ingredient, in this case fat, it should cost less than the standard product. That a food manufacturer may have incurred higher formulation costs to develop an acceptable reduced-fat product is an issue that many consumers seem unaware of and indeed probably have little interest in. A survey of European consumers funded jointly by the Pfizer Speciality Chemicals Group and the Calorie Control Council in 1991 showed similar trends in Europe to those identified in the U.K. study described above (Wagner, 1992). The research showed that the driving motivation among Europeans for consuming low-fat products was, generally, to stay in better overall health, although this reason stood out less prominently from others than it did in a comparable U.S. study by the same parties. For example, in France, ©1996 CRC Press LLC

reducing fat ranked higher than staying in better health, and reducing calories, maintaining weight, and maintaining an attractive physical appearance were ranked nearly as high as better overall health. In general, the findings suggested that the message of “reducing fat” had a stronger appeal to European consumers than Americans. Fat is also the number one dietary worry of U.S. consumers according to several statespecific and national surveys (Bruhn et al., 1992; Buss, 1993; CPQ, 1991; Gallup, 1990). For example, in a 1991 poll by the Food Marketing Institute, 42% of respondents ranked fat as the most important nutritional concern (Buss, 1993) while a California survey showed that as many as 62, 61, and 58% of respondents considered total fat content, saturated fat content, and cholesterol as “very important” in food selection (Bruhn et al., 1992). It appears that the U.S. consumer is responding not to an old-fashioned urge to “diet,” but to broader health recommendations by major groups such as the National Cancer Institute and the American Association of Diabetes that Americans reduce their fat intake to an average of 30% of total calories from the current average of 36% (Buss, 1993). However, the findings of a 1991 National Eating Trends study by the NPD Group, a marketing research firm, also suggest that Americans’ concerns about fat and cholesterol intake may be declining. Other studies show similar attitudes toward sugar, salt, and calorie intake. It should be stressed that this does not necessarily mean that healthful diets no longer interest people, but rather that the hysteria has subsided. The fact that the food supply now offers choices that make people feel more comfortable about cholesterol and fat is cited as one of the reasons for the drop in consumer concern regarding fat intake. Clearly, consumers’ concern and knowledge of the link between fat intake and health have heightened their receptiveness to the concept of reduced-fat foods, which in turn has led to increasing demand from food manufacturers for fat replacers.

3.3 MARKET DEVELOPMENTS IN REDUCED-FAT FOODS In response to consumer concerns over fat intake, an increasingly wide range of food sectors now offer reduced-fat and reduced-calorie versions of standard products. According to Wagner (1992), 76% of U.S. adults consume low-fat or low-calorie foods and drinks, while U.K. consumers are not far behind, with 74% claiming to consume lowfat and light products, ahead of German adults with 69% and French adults with 48%. Two in every three Australians have also been reported to consume reduced-fat and lowcalorie food products (Anon., 1993). While the message of “reducing fat” appears to have a stronger appeal to Europeans, they are nevertheless less inclined than Americans to incorporate low-fat, low-calorie, and sugar-free products into their diets. This phenomenon is put down more to market development and product availability than to a significant difference in attitudes between U.S. and European consumers. The most dominant segment of the “lite” consumer market in France, Germany, and the U.K. has been reported to comprise consumers of reduced-fat foods and reduced-fat beverages (Wagner, 1992). Penetration of low-fat foods in the U.K., at 67% of the population, was reported as virtually identical to that in the U.S. This compares with 54% in Germany, while France is still comparatively under-developed at 39%. In all four countries the incidence of use among women is 10 to 15% higher than for men. An examination of the specific types of low-fat products being consumed indicates that dairybased lines, such as low-fat cheese, yogurt, and cream are most popular overall, ranking number one in France (33% of adults) and Germany (47%). Low-fat beverages, e.g., low-fat instant chocolate drinks, are also very popular in the U.K. (35%) and Germany (33%). A more detailed account of developments specific to European and American markets for reduced-fat foods is given below. ©1996 CRC Press LLC

3.3.1 UNITED KINGDOM According to a study undertaken at the Leatherhead Food RA, the U.K. market for lowfat foods, including dairy products, meat products, snacks, ready meals, salad dressings, and pre-packed salads, grew by over 19% in 1992, to a retail value of nearly £2.1 billion (approximately $3.3 billion) (Comber et al., 1993). Dairy products dominated the market, accounting for around 90% of sales in 1992. Within the dairy products market, milk formed the largest sector, accounting for a 79% share. Meat products accounted for nearly 2.5%, while reduced-fat snack foods accounted for 2% and the “other” low-fat food products sector accounted for nearly 6% (Table 3.7). Table 3.7 U.K. Low-Fat Foods Market by Value (RSP in Millions of £) and Type, 1991–92 Year Product

1991

1992

% Change

Dairy products Milk Cream Cheese Yogurt Fromage frais Ice cream Spreads Meat products Burgers/grillsteaks Sausages Pâté Snack foods Other Ready meals Dressings Pre-packed salads Total

1,548 1,207 9 92 84 23 10 123 49 10 28 11 40 104 65 29 10 1,741

1,869 1,486 10 107 91 29 23 123 51 10 29 12 40 116 72 31 13 2,076

+20.7 +23.1 +11.1 +16.3 +8.3 +26.1 +130.1 0 +4.1 0 +3.6 +9.1 0 +11.5 +10.8 +6.9 +30.0 +19.2

From Comber, L.R., Cutler, A.J., and Griffin, P.F. Industry and Market Reviews, No. 19, 1993. With permission.

While most sectors of the low-fat food market in the U.K. are showing steady growth, some are showing dynamic growth, albeit from a small base, namely ice cream, prepacked salads, and fromage frais. While not evident from Table 3.7, reduced-fat bakery products are beginning to make an appearance on the U.K. market. The first reduced-fat biscuit (cookie) of note, namely Light Digestive from McVitie’s, appeared on the U.K. market in late 1992, and since then reports indicate that it has grown to a £7.5 million brand (approximately $12.5 million). The product now accounts for an estimated 10% of the U.K. digestive biscuit (cookie) market. As yet, there has been little activity outside biscuits (cookies). In this respect, the U.K. market is well behind that in the U.S., where retail sales of low-fat and low-cholesterol bakery products grew at an annual compound rate of 23.6% from 1989 to 1993. It is interesting to note that the largest sector, milk, is still one of those showing strongest growth, at over 23% in 1992, ahead of several smaller and newer low-fat product sectors such as meat products and snack foods. While consumer trends toward healthy eating and the reduction of fat in the diet continue to gain momentum, several low-fat food sectors have struggled to gain acceptance

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in the U.K., failing to meet consumer expectations in terms of taste and quality. Products that have performed best are those where, through the use of fat replacer technology, the food manufacturer has been able to offer products tasting nearly, and ideally equally as good as, the full-fat products they replace. This has been comparatively easy for a number of product sectors, in particular dairy products and dressings, which explains their high level of acceptance by consumers. The same is not the case for baked goods, where the technical challenges to be faced are more stringent and exacting. 3.3.2 EUROPE While data on the European market are somewhat patchy compared with those on the U.S., there is sufficient information to indicate a considerable and growing interest in reduced-fat foods, although it should be stressed that a number of market sectors are beginning to plateau and in some cases decline. According to several consumer surveys discussed in more detail earlier in this chapter, growing numbers (ranging from 64 to 76%) of adults (aged 18 and over) in Europe are selecting light foods and beverages to help them control their intake of fat and calories to stay in better overall health (Wagner, 1992). Based on these figures, it can be estimated that 81 million consumers in France, Germany, and the U.K. purchase light products, which is roughly 60% of the U.S. market (calculated at about 141 million consumers). Using similar extrapolations of survey data, it is estimated that there are 30.5 million light food and beverage consumers in the U.K. (75% of the adult population), 31.5 million light consumers in Germany (69% of adults) and 19 million light consumers in France (48% of adults). As in the U.S., the popularity of foods and beverages reduced in fat is the primary force behind the light food trend in Europe. Some 67% of British adults consume low-fat products, as do 53% of Germans, and 39% of the French. While very popular among men (as high as 61% penetration in the U.K.), these products are even more widely consumed by women in the three countries. The most popular low-fat products among Europeans are margarines, cheese, yogurt, cream and other dairy products, sauces, mayonnaise, and beverages (Wagner, 1992). Taking a closer look at the German market, it is apparent that, while light products are firmly established, market growth is modest. As in the U.S., reduced-fat dressings are the most popular reduced-fat foods. Reduced-fat salad dressings and mayonnaise accounted for 39% of total salad dressing and mayonnaise sales in the former West Germany for the period January to November 1992. This compares with penetration levels of 37 and 32% for the years 1991 and 1990, respectively. However, reduced-fat margarines appear to be growing in popularity, accounting for 12% of total margarine sales in 1992. This is 2% up on 1991 and 3% up on 1990. Penetration levels for reducedfat condensed milk and reduced-fat drinking milk have stabilized at 11% and 3%, respectively. Not surprisingly, penetration levels for light products in the former East Germany are considerably lower. For example, light salad dressings and mayonnaise accounted for only 16% of total salad dressing and mayonnaise sales in 1992, the same level as in 1991 (Staehler, 1992). A lower level of interest in reduced-fat foods in France compared with Germany and the U.K. has been reported (Anon., 1992). While sales of reduced-fat foods in France have in general grown in recent years, there are signs, as in Germany, that consumer interest is waning. Indicative of this was a 7.8% volume sales decline for reduced-fat spreads in 1992. While as a general rule the European consumer has shown a growing preference for healthier alternatives to traditional products, it is important to be aware of the strong regional variations relating to consumption of reduced-fat foods. As an example, it is possible to cite the considerable variation for penetration of reduced-fat

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milks across Europe. Since the data previously presented indicate that the French consumer has a lower level of interest in reduced-fat foods than the British and the Germans, it is somewhat surprising that France has one of the highest penetration levels for reducedfat milks in Europe, i.e., around 80%. This compares with penetration levels of around 50% in the U.K. and only around 20% in Germany. Higher preference for semi-skimmed products for most countries suggests that consumer desires to reduce fat intake are limited by taste. Other regional variations are also apparent, such as the comparatively more developed markets for reduced-fat meat products in Germany and reduced-fat bakery products in France. While the previous data appear at odds with earlier information on the French consumer’s attitude to reduced-fat foods, it further illustrates the danger in viewing the European market as homogeneous. 3.3.3 UNITED STATES While the numerous articles and reports on the U.S. market for reduced-fat foods may vary on its current value, all agree that it is a dynamic area. According to Mancini (1993), U.S. sales of low-fat processed foods are continuing to climb, from $29 billion in 1990, to $32 billion in 1991, to an expected $55 billion in 1996. Also indicative of the dynamism of the market was the launch of 519 new low-fat/low-cholesterol products in 1992, representing an increase of 39% over 1991, according to FIND/SVP (1993). Dairy products appear to be the most active category, accounting for one third of all low-fat foods introductions in 1992, followed by bakery products with 88 launches. This is also reflected in their sales value, which, at $10 billion, accounted for nearly 48% of total low-fat food sales in 1990 (Lakin, 1993). Sales are forecast to climb to $16 billion by 1995, or 32% of total low-fat food sales (Table 3.8). A recent study by FIND/SVP (1993) is even more bullish about the size and prospects for the U.S. market for lowfat/low-cholesterol dairy products. They forecast retail dollar sales to increase yearly, from $25.7 billion in 1992 to $39.3 billion in 1996, an average gain of more than 15% compounded annually. Table 3.8 Actual and Projected Sales of Low-Fat Food Products in the U.S. ($bn) Year Food product Baked goods Dairy products Frozen desserts Margarine Frozen ready meals Processed meats Salty snacks Total

1990

1995

1 10 3 2 2 2 1 21

6 16 7 2 6 8 5 50

From Lakin, J., Super Marketing, 46, 1068, 1993. With permission.

One of the major questions posed by a survey carried out by the Calorie Control Council has been: “Do U.S. consumers really like current reduced-fat products?” (Mancini, 1993). In the survey, some 69% of respondents claimed to be satisfied with the industry’s attempts at developing good-tasting products; however, nearly one third of respondents indicated that there was still scope for improvement. Mancini (1993) has

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suggested that one of the prime reasons for salad dressings being given as the category of low-fat foods most frequently purchased by adult Americans (55% of respondents) is that good-tasting reduced-fat versions can be achieved by the use of well-tried and tested ingredients, e.g., starch and hydrocolloids. The second most popular category of products have been low-fat dairy products (e.g., cheese and imitation sour cream) and reducedfat margarines, both reportedly purchased by 50% of the respondents. Reduced-fat milk, meat products, and ice cream/frozen desserts were consumed by 48, 39, and 38% of the consumers in the survey, respectively. It is suggested that since some of these foods are usually consumed with other foods (e.g., salad dressings and spreads), consumers tend to be more forgiving about any problems with texture and flavor. The fact that low-fat dairy desserts were only the sixth most frequently purchased line is felt to indicate that foods eaten primarily for pleasure rather than health have to satisfy more stringent criteria by consumers. As a consequence, it is therefore not surprising that low-fat baked goods and snacks are consumed less often. Dairy Field reports that despite some setbacks in early attempts at reduced-fat dairy products, new product development in the low-fat arena continues at a frenzied pace (Anon., 1993). Significant sales growth for reduced-fat variants is evident for most of the key dairy product categories, with many manufacturers seeing further opportunities for growth. There has been a proliferation of reduced-fat products in the sour creams and dips category, with no-fat and low-fat varieties now accounting for between 20 and 30% of total sales. Significant progress has also been made in reduced-fat cheeses, which, worth $750 million, account for 10% of total retail cheese sales. A 9% sales increase for reduced-fat frozen yogurt for the 52-week period ending August 15, 1993, is also indicative of the buoyancy of the low-fat frozen desserts category (Anon., 1993). While bakery products represent a relatively small part of the total market for lowfat foods, it is nevertheless one of the fastest growing categories, having grown at an annual compound rate of 23.6% over the period 1989 to 1993, according to FIND/SVP (Anon., 1993). However, while some products succeed — for example, Pepperidge Farm’s reduced-fat cookies, breads, muffins, and pita under the Wholesome Choice banner — others have not fared as well, e.g., Pepperidge Farm’s Wholesome Choice crackers, Sara Lee’s Free and Light, and Nabisco’s My Goodness. However, the growing importance of such products can be gauged from the fact that the market pioneer, Entenmann’s, now derives 20% of its sales revenue from its fat free range of baked goods. As for most other categories of the reduced-fat food market, good taste and quality are cited as crucial to success (Anon., 1993). While pundits may disagree on the level of growth, there is no doubt that the demand for reduced-fat variants of traditional products in the U.S. will increase. However, crucial to continued growth will be improvements in product quality, particularly for products eaten for pleasure rather than purely for health reasons. One can conclude from the information presented above that the market for reducedfat foods is buoyant internationally, although there are signs that interest may be waning in certain countries, e.g., France. The dairy sector has been at the forefront of this development, making a wide range of reduced-fat alternatives available to consumers. This has been possible due to the comparatively simple technology required to produce good-tasting reduced-fat alternatives to some dairy products. However, the technical challenges to be overcome in producing good-tasting reduced-fat baked goods and meat products are much greater, which explains their comparatively modest success to date. Based on what has been reported so far, one would expect that sales of fat replacers mirror those of reduced-fat foods. An examination of market developments specific to fat replacers now follows.

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3.4 MARKET DEVELOPMENTS FOR FAT REPLACERS In 1992, Morrison optimistically calculated that the maximum fat replacement potential in the U.S. was around 21 billion pounds, which equated to sales of around $46 billion, assuming a fat replacer price of $1.5 per pound. However, more recent reports suggest that fat replacers have not lived up to expectations. According to Consumer Reports, just a few years ago some analysts predicted that annual U.S. sales of fat replacers would quickly exceed $1 billion; however, by 1992 they still had not topped the $100 million mark (Anon., 1993). Another report states that even with the U.S. market for low-fat, low-cholesterol foods being worth $12 billion in 1990, fat replacers were only worth $100 million (Shuckla, 1992). It should be noted that the size quoted for the low-fat, low-cholesterol foods market, i.e., $12 billion, is considerably lower than that given earlier in this paper and serves to highlight that there are many contradictory figures surrounding the issue of low-fat foods and fat replacers. What this demonstrates is that there is a variety of formulation and processing techniques to reduce fat levels in many foods without resorting to the use of fat replacers. The consequences of this are reflected in the lower than expected sales figures for such materials. Data from Market Research International presented in the proceedings of the third annual IBC Conference, New Orleans, put U.S. sales of fat replacers even lower, at $60 million in 1991. Therefore, it seems unlikely that the combined U.S., European, and Japanese market for fat replacers will be worth $6.75 billion by the year 2000, as estimated by Shukla (1992). Nevertheless, there is no doubt that the potential exists for fat replacement across a wide range of food products. It is clearly unrealistic to expect the fat replacement potential to be fully realized, particularly as suitable materials are as yet not available, owing to either technological or legislative barriers. This is very much the case in the major areas of baking and frying fats. Clearly, heat-resistant fat substitutes have hardly begun to tap the potential that exists in the U.S. and elsewhere. Based on the data presented and the assumption that the U.S. fat replacer market is currently worth $80 million and growing at 10 to 15% per year, it is unlikely that sales will be worth much more than $200 million by the year 2000. With the U.S. accounting for around 50% of the world market, this would suggest worldwide sales of around $400 million by the year 2000. It should be stressed that this is a fairly cautious estimate that does not take into account a major influx of secondgeneration fat replacers offering improved levels of heat stability and end-product quality. However, owing to the considerable cost of developing such materials, both from a research and development and a safety stance, it is the opinion of this chapter’s author that this is unlikely to happen. The considerable problems encountered by Procter & Gamble in attempting to get olestra to market may also act as a deterrent to companies investing in this area.

3.5 CONCLUSIONS Data have been presented to indicate that fat is likely to remain the prime dietary worry for both U.S. and European consumers for the foreseeable future. This in itself will spur continued growth in the reduced-fat food markets of Europe and America, which in turn will increase demand for fat replacers. Many of the reduced-fat foods developed to date have been achieved through the use of existing carbohydrate-based thickeners and stabilizers combined in some cases with new processing technologies. While it is likely that carbohydrate-based fat replacers, i.e., maltodextrins, polydextrose, gums, etc., will continue to dominate the market for the foreseeable future, these will eventually lose some share to more sophisticated protein-based and synthetic products. However, the

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impact of synthetic fat substitutes on the market could well be blunted by regulatory delays and high price. Critical to the continued development of the reduced-fat foods market is the introduction of a wider range of good-tasting and textured products, particularly in the bakery and snack food sectors. This in turn will require that a broader range of fat replacers be developed; as has already been indicated, this can be an extremely expensive and risky business venture. However, for the company bold enough to tackle these problems, the rewards could be considerable. These views have been endorsed by a recent study by the Leatherhead Food RA on the current status and future opportunities for fat substitutes in Europe (Hilliam et al., 1995).

REFERENCES Anonymous, Lite food is popular, Food Technol., 29(10), 17, 1993. Anonymous, Reduced-fat bakery foods: meeting the taste challenge, Prep. Foods, 162(8), 79, 1993. Anonymous, Britain takes a healthy lead in Europe, Grocer, 214(7078), 34, 1992. Anonymous, Are marketers living a fat-free fantasy? Bakery Prod. Mark., 28(6), 132, 1993. Anonymous, Schwere Zeiten für Lights?, Lebensmitt. Prax., 15, 4, 1993. Boyle, C.S., Cathro, J.S., Comber, L.R., Emmett, S.E., and Hilliam, M.A. The U.K. low-fat food report, Ind. Mark. Rev. No. 6, 1991. Bruhn, C.M., Cotter, A., Diaz-Knauf, K., Sutherlin, J., West, E., Wightman, N., Williamson, E., and Yaffee, M., Consumer attitudes and market potential for foods using fat substitutes, Food Technol., April, 81, 1992. Buss, D., Trimming the fat from fat replacer expectation, Food Process., 54 (10), 44, 1993. Cathro, J., The U.K. Low-Fat Foods Report, 2nd Edition, Volume II — The Consumer, Ind. Mark. Rev., No. 19, 1993. Comber, L.R., Cutler, A.J., and Griffin, P.F. The U.K. Low-fat Food Report, 2nd Edition, Volume I — The Market. Ind. Mark. Rev. No. 19, 1993. Center for Produce Quality (CPQ), Two years after Alar: A Survey of Consumer Attitudes Toward Food Safety, CPQ, Newark, Delaware, 1991. FIND/SVP, Low-fat/low-cholesterol products hit new highs, Food Process., 54(3), 11, 1993. Gallup, Gallup Survey of Public Opinion Regarding Diet and Health, conducted for the International Food Information Council and American Dietetic Association, The Gallup Organization, Princeton, N.J., 1990. Hilliam, M., Angus, F., Bower, S., and Marriss, L., Fat substitutes — An in-depth European review of current status and future opportunities. Leatherhead Food Research Association Report, March 1995. Lakin, J., Fact file, Super Market., 46, 1068, 1993. Mancini, L., Low fat comes of age, Food Eng., 65(6), 149, 1993. Morrison, M. Fat replacers: potential markets. Inform 3(12), 1270-1277, 1992. Shukla, T. P., Low-fat foods and fat replacers, Cereal Foods World, 37(6), 452, 1992. Staehler, C., Out of the niche into the spotlight, Lebensmitt. Prax., 5, 4, 1992. Wagner, J., Global consumers want the lite stuff, Food Process., 53(10), 68, 1992.

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Chapter

4

Physical, Chemical, and Sensory Aspects of Fat Replacement Sylvia A. Jones CONTENTS 4.1 4.2 4.3 4.4 4.5

Introduction Mimicking the Fat Droplet Rheological Matching Physical Stability and Fat Reduction Sensory Implications of Fat Reduction 4.5.1 Intensity of Sensory Attributes 4.5.2 Temporal Effects of Fat Replacement 4.6 Flavor Release and Fat Reduction 4.6.1 Principles of Flavor Release and Methodological Considerations 4.6.2 Flavor Compounds vs. Flavor Perception 4.6.3 Flavor/Food Component Interactions 4.6.4 Flavor/Fat Replacer Interactions 4.6.5 Mass Transfer Inhibition and Flavor Release References

4.1 INTRODUCTION The principal objective of all the current product development activities in the area of fat reduction is to match the overall product characteristics of a full-fat variant. The degree of complexity of this task is dependent on the type of product and the level of fat reduction required, but the underlying cause of the difficulties experienced when reducing fat lies in its multifunctional nature as a food ingredient, and its often profound effects during the different stages of a product’s manufacture, as well as on the final

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product characteristics. Moreover, the problems are compounded by the fact that to date there is no permitted, commercially available single ingredient which can directly replace fat in all its food applications. Hence, the only viable route is to apply a holistic approach in fat reduction, whereby a fat-replacing system needs to be devised together with appropriate processing changes for each of the product matrices. Although there is a considerable range of commercialized fat replacers on the market, since the vast majority of these ingredients have hydrophilic characteristics, it is inevitable that in the majority of applications, fat reduction will be associated with an increase in water content, and this will lead to changes in physical, chemical, and sensory characteristics. A reasonable starting assumption, for instance in products which are in the form of an oil-in-water emulsion (e.g., milk, yogurt, cream, cheese, ice cream, soups, sauces, mayonnaise, dressings, etc.) could be to physically mimic a fat droplet. On the other hand, it may be more appropriate to attempt to match the rheological characteristics of the full-fat product through the use of different fat mimicking ingredients. However, while doing so, it would be necessary to achieve an acceptable product quality in terms of physical characteristics, physical stability, and sensory characteristics. Of equal importance in this context is the issue of microbiological stability as discussed in Chapter 1. Furthermore, since fat reduction is associated with changes in perceived product characteristics, it is essential to understand the physical and chemical implications of flavor release in the context of fat content manipulations. This chapter evaluates the scope for a scientific, systematic approach to fat reduction in the light of data reported in the literature, highlighting some of the more controversial aspects, with the aim of identifying the existing gaps in our scientific knowledge in the area of fat reduction.

4.2 MIMICKING THE FAT DROPLET In water-continuous food systems, the replacement of all or part of the fat can be viewed simply as the need to replace it with the same physical structure. It follows, therefore, that the concept of replacing oil droplets is equivalent to finding an ingredient or a system that can provide spherical particles which hopefully would behave similarly to oil droplets. This “ball-bearing” principle could, of course, be achieved easily by any of the synthetic fat substitutes (such as olestra) whereby both chemically and physically the structures are designed to be similar to fat. However, in the absence of commercial availability of such substances, a different approach has had to be taken toward identifying how such structures could be obtained using existing ingredients. This approach was explored in the development of Simplesse®, whereby through heat coagulation under continuous shear conditions, protein (with its natural tendency to form a continuous or semi-continuous network) was encouraged to form spherical, insoluble microparticulates of 0.1 to 3.0 µm in diameter (Singer and Dunn, 1990). Coagulated protein microparticulates can be obtained using different processes or processing conditions and/or through the use of proteins other than the whey protein concentrate used in Simplesse® 100. An overview of current literature on this topic has been published by Miller (1994). A puzzling and unresolved issue is whether or not, or to what extent, the microparticulation process is of particular significance. This was especially highlighted when Dairylight appeared on the market in 1989, since this ingredient, by design, does not attempt to mimic a fat globule structure, but is based on the fat mimicking properties of partial protein denaturation (see Chapter 1). However, if the goal is to mimic fat droplets more closely, it follows that the use of hydrophobic rather than hydrophilic gelled or semi-gelled structures should be pursued. In this context, zein protein obtained from corn gluten meal appears to provide interesting

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opportunities due to its hydrophobic nature and inherent insolubility in water. This concept was first explored by Enzytech, Inc. and then developed further by its branch Opta Food Ingredients, Inc., in the production of LITA® whereby the microparticulated zein protein is obtained through a special processing technique which includes the coating of the surface of the insoluble particle with a polysaccharide such as carboxymethylcellulose or gum arabic, in order to prevent aggregation of the particles (Cook et al., 1991; Iyenger and Gross, 1991; Stark and Gross, 1992). By definition, therefore, the nature of these microparticles, being very dense, nondeformable spheres, ranging from 0.1 to 8.0 µm in diameter, is quite different from those obtained through a heat or acid coagulation route. Although conceptually, LITA® is undisputedly a unique ingredient in terms of the source of protein used and its strong hydrophobic character, it should be noted that the same features are responsible for its major commercial drawback — i.e., its inherent flavor problems. On the other hand, LITA® is a product based on protein-polysaccharide interactions and considerable scope exists for exploring this concept in the pursuit of mimicking fat droplets. Another example of an ingredient based on protein-polysaccharide complex formation is Trailblazer range developed by Kraft General Foods (KGF). The principle behind Trailblazer is the fact that anionic polysaccharides interact strongly with proteins at pH values below their isoelectric points (Chen and Soucre, 1985; Chen et al., 1992). A typical Trailblazer product is made from xanthan gum, egg white, and whey protein. On heating, crosslinking through the formation of disulfide bond takes place resulting in a fibrous network. These are then subjected to a microfragmentation process which reduces particle size to approximately 10 µm. In physical terms, however, the structure of Trailblazer is that of fiber and therefore does not achieve the spherical ideal expected to give the maximum “ball-bearing effect.” Unfortunately, KGF decided not to commercialize the Trailblazer range and the interesting issue of the relative importance of structural differences in fat mimetics derived from the same protein (i.e., whey protein concentrate) remains open to speculation. Starch could be seen as an obvious ingredient to explore in the context of mimicking the fat droplet, but there seems to have been little activity in this area so far. Zhao and Whistler (1994) described an interesting process for forming spherical starch aggregates using starch granules (preferably from amaranth or wheat) by coating with sodium alginate or low methoxy pectin and then spraying with calcium chloride to form insoluble coatings. Although these spheres were developed for flavor-carrying purposes, it can be seen that the basic principle is similar to that employed in microparticulated proteins coated with hydrocolloids (as in LITA® and Trailblazer). On the other hand, if it is assumed that the actual physical shape is not important, then a fat mimetic such as Stellar™, which is based on a crystalline fraction of starch, could also be viewed as a microparticulated material since it is composed of aggregated starch crystallites which, when subjected to high shear in an aqueous system (minimum 8000 psi), form particles of 3 to 5 µm (Pszczola, 1991). A different concept of mimicking fat globules has been developed by the French company A and S Biovecteures (O’Donnell, 1994). The synthesis of a low-fat globule was based on a milk fat concept, whereby an internal lipid core was replaced by a reduced-calorie starch core but with the external properties of the globule modeled on a milk-fat globule. The process involves: obtaining a cross-linked modified starch; extruding the starch to obtain particle size with a diameter of approximately 2 µm; grafting a fatty acid layer to the starch particles using a nonpolar solvent or by supercritical fluid extraction technology; and attaching a phospholipid layer using a homogenization process. This concept for fat replacement was first introduced at the 1993 Food Ingredients Exhibition (FIE ‘93).

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It might be expected that the issue of mimicking the fat globule would be especially important in the absence of the dispersed phase, as in the case of a fat-free version of an oil-in-water emulsion. In such a case, a two-phase system of an emulsion can be devised by partitioning of the aqueous phase using the principle of biopolymers competing for water. Thus, depending on the choice of biopolymers and conditions such as water activity, pH, ionic strength, charge density, and biopolymer concentration, a mixture of two biopolymers can undergo complex coacervation (e.g., gelatin/gum arabic), or phase separation driven by thermodynamic incompatibility between biopolymers (e.g., gelatin/maltodextrin) (Tolstoguzov, 1986). In each case, it is possible to obtain a twophase system, and, in the latter case, mixed or filled gels with two or more 3D networks can be formed. Phase separation driven by thermodynamic incompatibility between biopolymers has been investigated for a wide range of mixtures, and proposed as an approach to fat reduction in the yellow fat spreads product area (Cain et al., 1989; Kasapis et al., 1992; Muyldermans and Vanhoegaerden, 1992). The above examples highlight some of the possible approaches to mimic physically the fat globule structure through the use of accessible ingredients, and, in most cases, special processing methods. It can be concluded that, although some means of “interrupting” the continuous aqueous phase is necessary, the extent to which it is necessary to mimic perfectly the size and shape of oil droplets remains questionable, as different approaches utilize a range of particle size beyond the 0.1 to 3.0 µm range originally considered as optimal, and the shapes range from distinct spheres to irregular particles. Moreover, despite attempts to limit hydrophilic activity, the “designer” particles could be expected to have different physical properties to those of fat on account of the differences in chemical structure. In other words, there are certain limitations in attempting to form the physical structure of a fat globule. However, the above discussion has focused on the mimicking of the fat globule structure in isolation. In reality, the complexity of real food systems necessitates optimization of the overall product formulation when replacing either all or a substantial amount of the fat by a fat mimetic. On the other hand, it may be considered as the need to obtain a fat mimetic system that would compensate for the broad spectrum of fat functionalities exhibited in a given product type. Glicksman (1991) suggested that a three-ingredient system is necessary for a good fat mimetic: (1) a thickening agent for lubricity and flow control; (2) a soluble bulking agent for control of adsorption/absorption of the food onto taste perceptors of the tongue; and (3) a microparticulate, generally insoluble, agent that acts like a ball-bearing to create smoothness. It can be postulated, however, that in order to mimic the different functions of fat in a substantially reduced-fat product, we must consider viscosity matching, solids adjustment, and particle size impact and mouthfeel, and we must also carefully balance the perceived flavor characteristics of the system. In other words, as has been emphasized previously, there is a need for a holistic approach.

4.3 RHEOLOGICAL MATCHING If matching the physical structure of a fat globule is elusive, then it is reasonable to take on board the effect (rather than the cause) of the physical and chemical characteristics of fat which manifests itself in the performance of the fat in foods. Here, rheological manipulation is the key. Thus, in the case of many product categories, reduction of fat in a given matrix can be seen as a challenge to mimic the rheological impact of fat through the use of a fat replacing system. However, although this is a viable and relatively easy route for the

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first stage of product/process development, due to the multifunctional nature of fat as an ingredient, a much broader perspective needs to be adopted to ensure that rheological matching is adequately corrected to encompass the impact of the reduced-fat level on the various functions of the fat in a given product (as discussed in Chapter 1). Hence, in general terms, rheological matching needs to be viewed in the context of its implications for: processability and handling; physical, chemical, and microbiological stability; and sensory characteristics (some of these issues will be discussed in more detail below). One aspect of the performance of fat that cannot be matched physically is that related to crystallinity and polymorphism. That does not mean, however, that it is not possible to use the rheological manipulation approach in foods dependent on fat crystallization for their characteristics. It is only in the case of products where fat forms the continuous phase, and its structure is solely based on the crystallization of fat, that the problems of rheological matching are compounded. But even here it does not mean that fat reduction cannot be achieved, merely that a different strategic approach needs to be adopted, taking into account the physical limit beyond which further fat reduction cannot be achieved. The issue of rheological matching can best be illustrated with reference to two products, namely table spread (margarine or butter) and chocolate, since each requires a different approach. Margarine (or butter) is a water-in-oil emulsion system containing 80% fat in which its particular end characteristics are highly dependent on fat crystallization. Despite that, it is possible to reduce the fat content by some 80% of the original level present in the margarine while still retaining the fat continuous nature of the product that is so important from the point of view of the product’s stability. What makes it a relatively easy task is the fact that it is an emulsion system, the overall rheology of which can therefore be manipulated by structuring the aqueous phase (i.e., the water droplets), manipulating the fat-water interface, manipulating the fat phase composition, and changing processing parameters. The fact that there are four variables means that considerable flexibility exists for matching rheological characteristics with the required sensory characteristics of the end product. It is not surprising, therefore, that the low-fat spreads market has developed to such a remarkable extent. Chocolate, on the other hand, is a much more difficult product because it is not an emulsion, but a fat-continuous suspension, the structure of which depends on the polymorphic behavior of the cocoa butter. This means that a fat replacement strategy involving hydrophilic fat replacers is not feasible, since the addition of even a small amount of water results in a significant increase in viscosity such that it would be impossible to process. But, even in this case, there are some avenues left to be explored. For instance, as illustrated by Daget and Vallis (1994), by modifying the fat composition and replacing some fat with a bulk filler (demineralized whey powder), fat content can be reduced from 35 to 25%. However, in the particular case of chocolate, if a more meaningful fat reduction is to be achieved, it is even more necessary to use the holistic approach than for any other product category, and there is the problem regarding compositional standards, and hence the labeling, claims, and marketing of such products (Jones, 1993). The use of low-calorie fats (e.g., Caprenin or Salatrim), or fat substitutes (e.g., olestra or esterified propoxylated glycerol) would, of course, make the task easier. However, the matter of rheological matching cannot be viewed in isolation but needs to be related to perceived sensory characteristics. While doing so, two issues come to the fore: first, how viscosity is measured (this issue was first explored by Shama and Sherman, 1973); and second, whether there are other rheological parameters or methodological matters that are of importance. On the other hand, the descriptors used to assess the contribution made by fat (or an ingredient or ingredient system that aims to replace

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it) have to be taken into account, as well as the implications of these descriptors to rheological measurements. The following brief examples from the literature should help the reader to understand the significance of these issues. The majority of published reports investigate the issue of fat replacement in oil-inwater emulsion systems since, on the one hand, it represents a large range of existing product categories, and, on the other hand, it is the easiest system to characterize and define from a scientific point of view. An oil-in-water emulsion exhibits non-Newtonian, shear thinning behavior. In a recent study, Mela et al. (1994) showed that an increase in oil content (in an oil-in-water emulsion containing 1.0% w/w of sucrose stearate as an emulsifier and fat content ranging from zero to 48%) gives rise to a logarithmic increase in viscosity (as measured at a shear rate of 48 sec–1), and that this viscosity increase was a predominant factor affecting perceived fat content as assessed by panelists. However, statistical analyses of the data showed that fat content made independent contributions beyond viscosity alone. Indeed, earlier work on perceived fat content and creaminess in thickened milks (Mela, 1988) led to the same conclusion. Other authors recognized the importance of two rheological parameters in relation to fat perception — i.e., viscosity and flow behavior index (power law index). Studying model soups with a range of thickeners, Wood (1974) established that, for this product, maximum perception of creaminess was at a viscosity of between 50 and 80 mPa.s, and a flow behavior index (n) of about 0.50. For desserts (creams with xanthan), Daget et al. (1987) found that maximum creaminess was at a viscosity of between 880 and 7500 mPa.s and a corresponding flow behavior index of 0.15 and 0.04 for 3.5 and 30% fat content, respectively. More recently, Daget and Joerg (1991) reported on a substantial study of model cream soups which examined the effects of several hydrocolloid thickeners on creaminess, thickness, and liking consistency in relation to rheological characteristics. The relationship between the flow behavior index and apparent viscosity was found to be different for each thickener. The maxima of “creaminess” corresponded to a viscosity of between 90 and 325 mPa.s and a flow behavior index of 0.12 to 0.42. Interestingly, rheological optima for liking consistency were found always to be lower than those for creaminess, while perceived thickness was found to be linearly related to the logarithm of viscosity for all thickeners. Thus, the results demonstrated the importance of the two rheological parameters in perceived creaminess and acceptability. However, the authors also established that other unknown aspects affected acceptability ratings in this study. Such aspects could be validated through a broader rheological approach. The importance of the size of oil droplets in relation to fat content and perceived fat content has also received some attention. The results reported by Mela et al. (1994) showed no apparent pattern in oil droplet size as affected by fat content in emulsions containing 0 to 48% fat. The decrease in oil droplet size resulting from different homogenization pressures used (100 and 300 bar) caused the viscosity of the emulsions to increase, but no difference was found in perceived fat content as a result of this viscosity increase. Richardson et al. (1993) studied the effects of homogenization and fat content on oral perception in 3.5 and 4.8% fat milks with and without the addition of carboxymethylcellulose. The results showed no effect of fat content or homogenization on viscosity (as measured at 50 s–1) for neither the unthickened milks nor for the milks thickened to the viscosity of a double cream. The ratings of “fat content” and “creaminess” were very similar; although higher scores were obtained for both of those attributes for nonhomogenized milks, these differences were not statistically significant as indicated by error bars. In the case of thickened milks, the responses obtained for perceived fat content and creaminess were again similar for all four milk samples and only the homogenized milk

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containing 4.8% fat received higher scores, but again, these were not statistically significant. Interestingly, despite the fact that the authors do not give any data on oil droplet size and distribution, they conclude that a high density of evenly sized particles (produced as a result of homogenization), together with adequately high viscosity, results in a realistic sense of creaminess. Although it is difficult to see the validity of this statement in the context of the results presented, and further work is obviously required, it would be expected that droplet size and distribution would have an effect on perceived fat content and creaminess, but it should be possible to, at least to some extent, depict such an effect in rheological performance. In this context, the results reported by Partel et al. (1994) should be mentioned, since they were able to relate mathematically rheological and particle size parameters. However, it should be pointed out that in this experimental work, extreme conditions were prevailing (in terms of both composition and methodology), and further work would be required to ascertain the validity of these findings in a low-fat context, as well as in relation to perceived flavor characteristics, since neither of these issues were included in the study. Baines and Morris (1988), confirming the results of earlier work on perceived thickness of solutions of polysaccharide thickeners in relation to viscosity measurement, postulated that the use of small-deformation oscillary measurement of viscosity at 50 rad–1 is necessary in order to account for the particular rheological behavior of xanthan, which is the result of its conformationally ordered structure (as opposed to “random coiled” disordered polysaccharide structures). A good correlation was found between viscosity and perceived thickness, while no differences were found in perceived thickness, stickiness, or sliminess. Interestingly, despite the extreme shear thinning of xanthan, no correlation was found between perceived sliminess and shear thinning. Moreover, no detectable suppression of perceived flavor or taste was found to exist when xanthan solutions of up to 1.0% (w/v) were studied. However, the issue of sensory attributes used to describe the contributions of fat (or fat mimetic) in textural terms are far from being resolved, despite the fact that there has been a substantial amount of research activity in this area (Szczesniak et al., 1963; Jowitt, 1974; Szczesniak, 1979). The elusive term of “creaminess,” for instance, was reported to be unrelated to terms such as “thickness,” “smoothness,” and “slipperiness” (Cussler et al., 1979). While Kokini et al. (1977) defined each of the latter three desriptors in terms of friction and/or viscosity, Cussler et al. (1979) suggest that “creaminess” cannot solely be related to the three above mentioned attributes, and hence it cannot be defined in rheological terms. On the other hand, Drewnowski (1987), in a study on liquid dairy foods (from milk to heavy cream) suggests that the fat content may be better monitored and perceived through the use of more abstract terms related to caloric density (e.g., oily, greasy). It is noteworthy that the response received for the term “creamy” was very similar to that received for the terms “fattening” and “high calorie.” While there appears to be some confusion in the reported data with regard to the sensorily measured responses to fat content, on the basis of a closer examination of the data it can be postulated that the current state of flux has its origins in two factors: first, the sensory methodology used (e.g., consumer vs. trained panelist, brief given on the products, the level of understanding of the terms assessed, presence or absence of reference points, etc.); and second, the type of attribute used. In the latter case, two categories of attributes can be distinguished. The first comprises terms that are unaffected by hedonic response (e.g., thickness, smoothness, slipperiness, fattening, high calorie), and hence an approximately linear relationship would be expected between the intensity

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of these attributes and fat content, and these terms could be defined in rheological terms. On the other hand, the attribute “creaminess,” which is considered by most authors as the best descriptor for the assessment of the contribution made by fat to perceived sensory characteristics of a product, is much more complex, since it involves a certain level of hedonic response. For that reason, the response for this attribute would be expected to be nonlinear. This can vary from a curve response with a plateau, as first obtained by Wood (1974), to an inverted U-shape response against increasing fat content, since a point will be reached where a further increase in fat content is deemed inappropriate for the particular product type. Obviously, it is not feasible to attempt to define such an attribute in rheological terms alone. Moreover, it can be postulated that in any given product, apart from thickness and smoothness characteristics, perceived creaminess will also be affected by the intensity of flavor attributes present in the system. Overall, it can be concluded that while considerable scope remains in rheological matching of the contribution made by fat with that of a fat replacing system, the issue needs to be viewed in the context of the complexity of a particular product matrix and its quality parameters. While rheological characteristics undoubtedly play an important role in sensory perception of foods, the extent to which this route is sufficiently explored is debatable. It could be postulated that more attention should be given to physically mimicking the conditions in the mouth prior to proceeding with rheological characterization, which should, perhaps, be designed in relation to the product’s matrix. On the other hand, the limitations of rheological characterization alone should be recognized, especially where flavor intensity and flavor release affect the perceived rheological characteristics.

4.4 PHYSICAL STABILITY AND FAT REDUCTION Fat reduction can have a profound effect on the physical stability of a product. One of the important roles of fat replacing ingredients, therefore, is their ability to maintain physical stability while at the same time providing acceptable quality in sensory terms. The importance of this issue was demonstrated when some products launched in the early 1990s suffered from apparent physical instability and had to be withdrawn from the market (e.g., some low-fat spreads and hard cheeses). Little published data exist on physical characteristics and stability in relation to fat reduction in foods, and virtually none at all that attempts to relate fat content and physical characteristics and stability to sensory characteristics. In practice, the issue of physical stability is compounded when moving from water-continuous liquid products to oil-continuous semi-solid products. For present purposes, the subject of changes in physical characteristics in relation to fat replacement will be illustrated with water-in-oil emulsions — i.e., spreads. Various test and characterization procedures for assessing low-fat spreads were investigated by Bavington et al. (1992) using ten commercially available spreads ranging in fat content from 20 to 40%, and containing different aqueous and fat phases. All the techniques employed were able to distinguish between the spreads, with the results from conductivity measurements and stability tests correlating well with their observed microstructure. Other techniques such as differential scanning calorimetry, and solid fat content, spreadability, and texture measurements measured by penetrometry, were primarily related to the hardness of the spreads, although the spread microstructure also influenced the results obtained from these tests. Most of the physical tests performed were found to be related to the results obtained from sensory analysis of the spreads, since the textural characteristics tended to dominate sensory discrimination (see Section 4.5.1). Spreads

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with no aqueous phase stabilizers were found to have the smallest aqueous phase droplet size, while hardness and spreadability of the spreads were primarily, though not exclusively, related to the solid fat content. Other spread characteristics, such as stickiness, cloying character, the rate of breakdown in the mouth, etc., were dependent upon the type of aqueous phases stabilizers and the openness of the spread microstructure (Bavington et al., 1992). Figure 4.1 gives an example of some of the differences in selected physical characteristics for three of the ten commercial low-fat spreads investigated in relation to the composition of the aqueous phase as indicated on the labels. It is apparent, therefore, that low-fat spreads produced commercially differ considerably in terms of their physical characteristics. Overall, the differences in physical characteristics can be attributed in general terms to four main factors: fat content; composition of the aqueous phase; composition of the fat phase; and processing methods/conditions used.

Figure 4.1 Differences in selected physical characteristics of some of the commercial 40% fat spreads: Sample 2, containing sodium caseinate and sodium alginate; Sample 5, containing modified starch and milk proteins; Sample 6, containing gelatin and milk proteins. (Compiled from Bavington et al., 1992.)

In low-fat spreads containing 30% fat or less, the primary concern is to maintain a waterin-oil emulsion structure. In standard processing methods, this can easily be achieved using an appropriate emulsification system, which will allow the formation of the emulsion

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and the maintenance of the water-in-oil emulsion structure during processing (Clegg et al., 1993). However, while in physical terms an excellent emulsion can be achieved, with small water droplets (0.5 to 2.0 µm) homogeneously distributed throughout the continuous fat phase, the emulsifiers necessary for obtaining such a stable system give rise to undesirable organoleptic characteristics which manifest themselves predominantly in textural attributes (e.g., the slow rate of emulsion breakdown in the mouth), and these, in turn, affect flavor release characteristics of the spreads. Thus, certain changes in product formulation are necessary if an acceptable quality is to be achieved. It is now an established commercial practice to use hydrocolloid stabilizers, either polysaccharide-based (e.g., starch, maltodextrin, sodium alginate) or protein-based (e.g., gelatin or sodium caseinate), in order to structure the aqueous phase of the low-fat spreads (Bavington et al., 1991). Such ingredients thicken and gel the aqueous phase droplets, giving rise to rheological changes that affect the different stages of manufacture, as well as the physical stability of the final product, which will be dependent on the type and concentration of the hydrocolloid(s) used. Clegg et al. (1993), in a study of the role of aqueous phase stabilizers in low-fat spreads containing 30% fat, demonstrated an apparent destabilizing effect of hydrocolloids on the physical characteristics of the final product. This was manifested in an increase in droplet size, changes in droplet size distribution, and a decrease in thermal and shear stability compared with spreads containing no aqueous phase stabilizers. A confocal laser scanning microscopy technique was used to study changes in microstructure in order to ensure minimum disruption of the spread systems, and also to be able to view the structure in three dimensions. While slight destabilization was observed for spreads containing gelatin and those containing gelatin and maltodextrin, a marked increase in droplet size was found in spreads containing gelatin and sodium alginate. In the case of spreads containing gelatin and modified starch, a significant destabilization was found, with evidence that some of the starch was disrupting the crystalline fat phase structure. Extensive destabilization was found in spreads containing gelatin and sodium caseinate as a result of the surface active properties of the sodium caseinate, and its tendency to promote a water-continuous emulsion, which was therefore counteracting the action of the emulsifiers present. However, while at a lower concentration of sodium caseinate the microstructure of the spread was more or less bi-continuous in nature, at higher concentrations of sodium caseinate the increased viscosity of the aqueous phase tended to counteract to a certain degree the surface active properties of the protein, thus limiting the extent to which the aqueous droplets coalesced during and after processing. As a result, some restabilization was apparent, and the presence of aqueous lakes and large droplets was evident. Figure 4.2 shows confocal images of selected low-fat spreads from these studies (Clegg et al., 1993). On the other hand, destabilization of the water-in-oil low-fat emulsion systems, as affected by the presence of hydrocolloids, has an important positive effect on sensory characteristics in terms of the rate of emulsion breakdown in the mouth, melt-down properties and flavor release. In other words, a certain degree of instability needs to be introduced into a necessarily tight and stable low-fat oil-continuous emulsion system (which is needed to enable processing) in order to mimic the sensorily perceived characteristics of the full-fat spread. In addition, the source of the fat blend, the melting profile of the fat, and the ratio of liquid to crystalline fat affect the structure of the emulsion and organoleptic characteristics. A more extensive discussion of the sensory implications of fat reduction is given in Section 4.5.

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a

b

c Figure 4.2 Effect of aqueous phase stabilizers on microstructure of 30% fat spreads obtained using confocal laser scanning microscopy technique: (a) no aqueous phase stabilizers; (b) 2% gelatin/15% maltodextrin; and (c) 2% gelating/8% sodium caseinate. (From Clegg, S. M., Moore, A. K., and Jones, S. A., Leatherhead Food Res. Assoc. Res. Rep. No. 715, 1993. With permission.)

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4.5 SENSORY IMPLICATIONS OF FAT REDUCTION Changing the fat content of a product can have a significant impact on sensory characteristics, and, as indicated earlier, all the main attributes (i.e., appearance, flavor, mouthfeel, and texture) may be affected. How much of an impact this will have depends on the product type and structure, the extent of fat reduction, and the extent (broadly speaking) of measures taken to compensate for the effects of fat reduction in product reformulation or process modification. In the early days of fat replacement, the major emphasis was placed on counteracting the loss of rich and creamy textures as a result of fat removal. The issue of flavor was seen as secondary. However, if the quality of a full-fat product is to be matched after reducing fat content, it should be obvious that both aspects need to be considered on a more or less equal basis, especially as they are interrelated. Indeed, it can be argued that since flavor is normally regarded as the most important factor in consumer choice, it is that which should be given the higher priority. The problem is that the functionality of texture determining ingredients and their interactions are much better understood than flavor changes in food systems as affected by changes in composition. Nevertheless, significant progress has been made in recent years. 4.5.1 INTENSITY OF SENSORY ATTRIBUTES Any changes in formulation are likely to affect the intensity of sensory characteristics, and in the case of fat removal, this issue is especially important. The impact of fat removal in a given product can be demonstrated by evaluating sensory changes as a result of uncompensated fat reduction. Figure 4.3 depicts the changes in sensory response as a function of fat reduction in model spreads (water-in-oil emulsions) where distilled monglyceride and polyglycerol polyricinoleate were used in each case at 0.4% of the aqueous phase using no water structuring ingredients. While retaining constant compositional and processing parameters, with only the fat content as a variable, a clear change in the dimensions of the star diagrams can be observed when moving from 80 to 20% fat, with a statistically significant decrease in flavor intensity for attributes such as lactic butter, sweet, sour, and rancid. Thus, when using a minimal or no compensation approach, it is possible to identify the limiting attributes associated with fat reduction. Hence, the attempts to compensate for fat reduction through the use of other ingredients can be seen as efforts to match the sensory profile of the full-fat product. In reality, however, this is an oversimplification, since, if the goal is to achieve a significant fat reduction, in most cases, other issues have to be addressed alongside (e.g., physical stability, as discussed earlier). Therefore, the formulation and/or processing changes required would normally result in a more complex flavor profile. When developing a low-fat version of a product category that has a number of products already commercialized, it is useful to evaluate the existing products in order to establish how they differ from the full-fat variant. In addition, an insight can be gained into the viability of the approaches used in fat replacement if that is put into the context of the relative performance of these products on the market. The use of consensus profiling based on the Quantitative Descriptive Analysis (QDA) method, combined with analysis of variance (ANOVA), followed by principal components analysis (PCA) is a useful technique that enables the acquisition of such information. Figure 4.4 shows the position of 13 commercial spreads with respect to the first two principal components (Kilcast at al., 1991). The fat content of the products shown ranged from 80% (standard margarine) to 25%. The plot can be regarded as a perceptual space showing the perceived interrelationship between the test samples. Samples that are

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Figure 4.3 Effect of fat content on intensity of flavor attributes in oil-continuous spreads (fat reduction not compensated by compositional changes). (From Jones, S. A. et al., unpublished. With permission from the Leatherhead Food Research Association.)

positioned close to one another in the plot were perceived as having similar sensory characteristics, whereas those distant were perceptually different from one another. The original sensory attributes are shown as vectors radiating from the origin of the plot and lengths of the vectors represent their relative importance in the principal component space. For clarity, only the more important vectors are shown in Figure 4.4, but these are derived from panelists’ evaluation of 16 attributes reflecting appearance, flavor, texture, and mouthfeel characteristics. The data show that the two full-fat margarines, and one of the 40% fat spreads are clearly separated from the other samples on the basis of paler yellow color, smoother texture, and more glossy appearance. However, this 40% spread is differentiated from the others on the basis of high levels of lard flavor and lack of saltiness. The rest of the low-fat spreads are positioned more to the right of PC1, and were generally darker yellow in color, with a more grainy appearance. The product containing the lowest amount of fat of those tested (i.e., 25% fat) is clearly separated from the others on account of its gelatinous and firm characteristics, whereas the 40% fat located closest to it is characterized by a firm texture as it is based on butter.

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Figure 4.4 Positioning of a range of commercial fat continuous spreads with respect to each other and discriminating attributes (PC1 vs. PC2). (From Kilcast, D., Crawford, B. A., and Foster, Leatherhead Food Res. Assoc. Res. Rep. No. 683, 1991. With permission.)

Although there are some published reports on the effects of different fat replacers in food systems, virtually none consider a full sensory characterization of the products studied with the aim of relating that to physical characteristics in order to gain an understanding of the precise role each ingredient fulfills in fat replacement. As a result, the development of low-fat foods is to a large extent left to the empirical approach of trial and error. However, in the previously mentioned study, Clegg et al. (1993) investigated the effects of a range of fat mimicking ingredients in relation to both physical and sensory characteristics. Figures 4.5 and 4.6 illustrate the effect of maltodextrin concentration on flavor and texture attributes, respectively, in low-fat spreads containing 30% fat. The results show that the addition of maltodextrin gave rise to a significant perception of soury, nutty, and margarine notes which coincided with a decrease in vegetable oil flavor. With respect to texture, the incorporation of the maltodextrin at a higher level (15%) resulted in the product showing a significantly increased rate of breakdown in the mouth which corresponded with a decrease in perceived waxiness. This product was also found to have the least gelatinous characteristics of all low-fat spreads tested in this study (Clegg et al., 1993). In Figure 4.7, a principal component plot for flavor is given showing the relative positioning of all low-fat spreads tested. It can be seen that PC2 clearly separates the maltodextrin containing spreads on account of their higher level of margarine flavor, which is a positive attribute. On the other hand, PC1 differentiates between all the samples on the basis of relative intensity of vegetable oil which is a negative attribute related to the ability to break down the water-in-oil emulsion structure in the mouth. Hence, flavor intensity of attributes such as sweet, butter, and salt are inversely related to the vegetable oil intensity and the spread containing 8% sodium caseinate is clearly separated from other spreads in the PC1 dimension in a positive direction. The effects of other hydrocolloids on flavor characteristics of low-fat spreads investigated in this study are to a

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Figure 4.5 Effect of maltodextrin on flavor attributes of low-fat spreads. (From Clegg, S. M., Moore, A. K., and Jones, S. A., Leatherhead Food Res. Assoc. Res. Rep. No. 715, 1993. With permission.)

large extent depicted by their positioning in a negative direction of the PC1 dimension, and they are related to the size and distribution of the aqueous droplets, as indicated in Section 4.4. It is apparent from the foregoing that structural changes in the emulsion found as a result of the addition of hydrocolloids were well reflected in sensory characteristics, and that the textural characteristics were determining flavor changes as a result of the impact of structural changes on flavor release. 4.5.2 TEMPORAL EFFECTS OF FAT REPLACEMENT Using fat mimetics to compensate for fat removal leads not only to changes in intensity of the different flavors but also can have significant effects on temporal characteristics of flavor perception. The time-intensity technique allows the determination of a graphical relationship between the perceived strength of a sensory attribute and the duration of its perception (Wyeth and Kilcast, 1991). The various parameters that can be obtained from a time-intensity curve include onset time of response; maximum perceived intensity; time to reach maximum intensity and its duration; and rate of decay of response.

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Figure 4.6 Effect of maltodextrin on texture attributes of low-fat spreads. (From Clegg, S. M., Moore, A. K., and Jones, S. A., Leatherhead Food Res. Assoc. Res. Rep. No. 715, 1993. With permission.)

Figure 4.8 shows mean time-intensity curves for sharpness, bitterness, and astringency as perceived by panelists when evaluating reduced-fat and full-fat versions of commercial Cheddar cheese (Shamil et al., 1991). The rate of flavor release was greater, and the total intensity of all attributes tested was higher in the reduced-fat Cheddar cheese as a result of a longer persistence time of response. This indicates a changed flavor balance which may have an important effect on consumer acceptability. In another experiment, the effects of two starch-derived fat mimetics, Paselli SA2 and N-Oil, were studied in a 30% salad cream formulation in which the maltodextrin/water system replaced 50% of the fat (Shamil et al., 1991). This was evaluated against a fullfat product (30% fat) acting as a control. Figure 4.9 shows the results obtained for perceived saltiness and vinegariness. The reduced-fat salad dressings containing 15% fat were perceived to have a higher intensity of vinegariness, and a longer persistence time in the mouth compared with the full-fat control, while saltiness showed the opposite

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Figure 4.7 Effects of aqueous phase composition on positioning of low-fat spread samples with respect to each other and discriminating attributes (PC1 vs. PC2). Sample 1, no aqueous phase stabilizers; sample 3, 2%-gelatin; sample 5, 2%-gelatin/10%-maltodextrin; sample 6, 2%gelatin/15%-maltodextrin; sample 7, 2%-gelatin/2.5%-modified starch; sample 8, 2%-gelatin/5%-modified starch; sample 9, 2%-gelatin/1%-sodium alginate; sample 10, 2%-gelatin/2%sodium alginate; sample 12, 2%-gelatin/8%-sodium caseinate. (From Clegg, S. M., Moore, A. K., and Jones, S. A., Leatherhead Food Res. Assoc. Res. Rep. No. 715, 1993. With permission.)

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Figure 4.8 Mean time-intensity curves for perceived sharpness, bitterness, and astringency in reduced- and full-fat cheddar cheeses. (From Shamil, S., Wyeth, L. J., and Kilcast, D., Leatherhead Food Res. Assoc. Res. Rep. No. 687, 1991. With permission.)

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Figure 4.9 Mean time-intensity curves for perceived saltiness and vinegariness in full- and reduced-fat salad dressings. (From Shamil, S., Wyeth, L. J., and Kilcast, D., Leatherhead Food Res. Assoc. Res. Rep. No. 687, 1991. With permission.)

trend. While clearly significant differences between the control and the two reduced-fat samples were apparent, the Student-Newman Keuls multiple comparison test showed no statistically significant differences between the use of Paselli SA2 and N-Oil. The results obtained in the experiments described above can be explained in terms of the hydrophobic/hydrophilic characteristics of the compounds responsible for the measured sensory characteristics; the relative concentrations of these compounds in water/fat phases; and overall, the impact of fat replacement on the flavor release mechanism (the latter point will be discussed in Section 4.6).

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Daget and Vallis (1994), in their study on fat replacement in milk chocolate through the manipulation of solid fat index and the addition of a bulk filler, also investigated the temporal effects of such formulation changes. The authors established that although the fat reduction from 35 to 25% itself had hardly any effect, the solid fat index had a significant influence on several time-intensity parameters in milk chocolate, with a lower solid fat index (50%) being associated with a more rapid perception of sweetness, as well as a higher sweetness intensity compared with a higher solid fat index (70%). The above examples merely illustrate the importance of monitoring temporal characteristics of flavor perception in the context of fat replacement, but there is an obvious scope for the time-intensity technique to provide a greater understanding of the relative changes in flavor balance in relation to flavor release mechanisms.

4.6 FLAVOR RELEASE AND FAT REDUCTION 4.6.1 PRINCIPLES OF FLAVOR RELEASE AND METHODOLOGICAL CONSIDERATIONS When a food is placed in the mouth, it is subjected to: a thermal effect as a result of body temperature impact; a dilution effect as a result of the presence of saliva; and textural changes in the food matrix as a result of mastication and the presence of protein and a-amylase in saliva. The perception of flavor is the result of the chemical stimulation of receptors in both the oral and nasal cavities, and while tastes are perceived on the tongue (saltiness, sweetness, sourness, bitterness), the trigeminal factors of astringency, pungency, and cooling are perceived in the soft membranes of the mouth, the nasal cavity, and the throat, and the volatile components released during mastication diffuse through to the nasal cavity, toward the olfactory epithelium. It follows, therefore, that though the nature and amounts of the volatile aroma and nonvolatile taste components present will directly affect flavor perception, the availability of these compounds to the receptors is probably even more important. In physical terms, two major factors determine the rate and extent of flavor release: first, the partitioning of flavor compounds as affected by the composition of the food; and second, the resistance to mass transfer (i.e., diffusion and mastication) as affected by texture (Overbosch et al., 1991; de Roos and Wolswinkel, 1994). The effect of partitioning in relation to flavor release has been given significant attention over the years using the headspace analysis technique. However, no attempt has been made to relate such data to flavor release as measured by sensory techniques. Conversely, few data exist on the effects of mass transfer on flavor release, and no attempt has been made to relate such data to headspace analysis. Another criticism that can be made with regard to most scientific research on flavor release is that usually very simple model systems have been used, and in some cases, the levels and/or types of components used were unrealistic or bore little relevance to foods. In addition, the strong focus on volatiles left the important area of the perception of taste compounds hardly touched. On the other hand, research activity directed toward developing instrumental methods that attempt to mimic flavor release in the mouth or allow particular aspects to be studied has been quite significant. Table 4.1 lists a number of useful analytical methods in relation to different stages in the flavor release process (Plug and Haring, 1993). The original approach of headspace analysis under static conditions gave results that were of limited value in relation to in-mouth conditions prevailing during consumption. In order to address this problem, attempts are made to mimic in-mouth conditions (including temperature, shear, air flow, and the presence of saliva) with a view to developing a mouth analogue. A comprehensive overview of developments in instrumental methods has been

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given by Overbosch et al. (1991). Recent advances in using a direct approach of measuring the release of volatile compounds in exhaled breath using a mass spectrometer as a detector have been discussed by Reid and Wragg (1995). The authors constructed a membrane interface to allow direct introduction of volatile compounds into a mass spectrometer and optimized conditions for in-breath flavor analysis using different mass spectrometric ionization techniques. Thus, significant progress has been made in the direct application of mass spectrometry to study flavor release and there is obvious scope for expanding further the use of this technique to monitor the effects of flavor release as affected by fat content in food systems. Table 4.1 Stages in the Flavor-Release Process and Corresponding Methods of Analysis Location of process

Process

Analytical method

Product (prior to digestion) Mouth Mouth/respiratory tract Respiratory tract/nasal cavity Nasal cavity Mind

Binding of flavor to food ingredients Liberation of flavors Flavour absorption by mouth tissue Transport of flavors to nasal cavity Interaction with olfactory epithelium Flavor perception

Headspace analysis Mouth analogue None available In-nose MS-breath analysis None available Sensory analysis

From Plug, H. and Haring, P., Trends Food Sci. Technol., 4, 150, 1993. With permission.

The issue of flavor release in the mouth is very complex, and a number of research groups have tried to address the problem through the development of mathematical models that could describe the physical and chemical aspects of the release of flavor volatiles during food consumption (see Overbosch et al., 1991). Undoubtedly, this approach could have great potential for use in the development of low-fat or fat-free products, provided that its scope was sufficiently broad to encompass the multiplicity of issues of importance in fat replacement. Currently, research in this area is being carried out jointly by the Leatherhead Food Research Association and the Institute of Food Research, Reading (U.K.) under the U.K. government’s LINK scheme, which aims to address the issue of improving the flavor quality of low-fat foods (both oil-in-water and water-in-oil food systems). 4.6.2 FLAVOR COMPOUNDS VS. FLAVOR PERCEPTION Fat not only delivers its own flavor volatiles but also functions as a carrier for other lipophilic compounds present. These are bound to the fat molecules by weak, reversible Van der Waals and hydrophobic interactions (Plug and Haring, 1993). It follows, therefore, that in the case of total fat removal, with the flavor cocktail used remaining unchanged, the changed kinetics of the flavor release mechanisms will cause the perceived flavor of the product to be changed perhaps quite dramatically. In this context, the effects of pH on flavor compounds need to be borne in mind. Thus, because of concerns regarding microbiological stability, it is common practice to make the pH of a food product lower when reducing fat content in order to ensure a sufficient shelf life. This can have a significant impact on acid-base flavor compounds, since mostly they exhibit a particular flavor only if in the associated state. Since this would depend on the pK value of the compound, changes in pH can result in more molecules in the dissociated state, thus leading to the loss of flavor perceived. According to Bennett (1992), lowering the pH of a product from 6.5 to 4.2 results in a ten-fold increase in the associated form of butyric acid which has obvious implications for fat replacement in dairy products.

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Furthermore, the amount of fat that is removed and the amount of water added to a food system will affect not only the perceived intensity of both the lipophilic and hydrophilic flavor compounds present but also the flavor balance. This point is illustrated in Table 4.2 which compares flavor threshold values of flavor compounds when placed in a water medium and when placed in an oil medium (Bennett, 1992). Thus, the threshold value for decanoic acid, for example, will change by 5000% when moving from oil to water. In short, the need for changes in the composition of the flavor cocktail used when developing low-fat or fat-free foods is rather apparent. Table 4.2 Comparison of Flavor Threshold Values for Fatty Acids in Water and Oil Threshhold (ppm) Fatty acid 2:0 4:0 6:0 8:0 10:0 12:0

(Acetic acid) (Butyric acid) (Hexanoic acid) (Octoanoic acid) (Decanoic acid) (Dodecanoic acid)

Water

Oil

54 7 5 6 4 —

— 0.6 3 350 200 700

From Bennett, C. J., Cereal Foods World, 37, 429, 1992. With permission.

4.6.3 FLAVOR/FOOD COMPONENT INTERACTIONS Lipids have a major effect on equilibrium headspace concentrations of flavor volatiles (Land, 1979), and therefore, if the amount of fat in a product is reduced or removed from a formulation, it is of interest to know what the interactions between the flavor compounds and other food components are in order to ascertain the potential implications of using these components in fat replacement. It should be emphasized that the brief overview of current knowledge in this field given below is based on studies on simplified model systems, with the static headspace analysis method being used to evaluate flavor release, and hence the available data deals only with the partition phenomena. (The issue of mass transfer is discussed in Section 4.6.5.) Solms (1986), when reviewing research carried out in this area in the 1970s and 1980s, concluded that proteins had relatively weak lipophilic interactions with flavor compounds with discreet binding zones, but the binding properties changed with the degree of protein denaturation, pH, ionic strength, and temperature. Dumont (1987) investigated flavor-protein interactions under nonequilibrated conditions (as opposed to equilibrated static systems) for volatile as well as nonvolatile flavor compounds. He concluded that perceived flavor is lowered through ligand binding to protein, but that the binding is reversible. Moreover, he postulated that rate of ligand release from protein was a major contribution to flavor persistence, which indicated the need to study flavorprotein interactions in the time dimension. Overbosch et al. (1991) confirmed those conclusions and stated that a low level of unspecific hydrophobic reversible binding of flavor compounds to proteins has a small effect on flavor components in food. However, the authors indicated that aldehydes and diacetyl show specific irreversible pH-dependent binding to proteins high in arginine and lysine, which implies that a significant effect on flavor release would be seen in products containing gelatin. While Bennett (1992) is in general agreement with Overbosch et al. (1991), he indicated that as a result of chemical binding between aldehyde- or ketone-based flavor compounds and proteins, a

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product with no flavor impact could result. Plug and Haring (1993) have suggested that the results of studies on the relationships between the molecular structure of flavor compounds and their binding to proteins have not always been consistent, probably because of the conformational differences in the proteins tested. In the case of starch, Solms (1986) postulated that specific interactions occurred as a result of compounds entrapped in the helical structures of the gelatanized amylose fraction of starch, but, in the case of degraded starches, a loss of binding properties occurs. Overbosch et al. (1991) concluded that no overall insight exists into the mechanism of flavor binding to carbohydrates, and that the effects encountered are mostly reversible. In contrast, while Bennett (1992) supports the view that flavor compounds form complexes with amylose, he also indicated that in a system low in fat, it would be expected that a lipophilic flavor compound would not be able to react with the olfactory receptors until a breakdown of the helix structure had occurred as a result of the enzymic activity of the α-amylase in the mouth, which would be unlikely to happen before swallowing. In the case of polysaccharides, due to their highly polar nature, while interactions with lipophilic flavor compounds will not occur, there will be interactions with hydrophilic flavor compounds through dipole-dipole and hydrogen bonds (Plug and Haring, 1993). Baines and Morris (1987), in a study of perceptions of flavor and taste in guar gum solutions, concluded that since, on the one hand, they obtained the same ratings for flavor and sweetness perception, respectively, and on the other hand, the physiological mechanisms and receptors involved in the two cases are quite different, direct binding of flavor or taste molecules to guar gum does not seem likely, especially since the concentration of guar gum showed no effect (up to approximately 1.7% w/v). Overall, it can be concluded that our understanding of the interactions between flavor compounds and food components is still quite limited, and progress in this area will depend on developments in methodologies used to monitor flavor release. 4.6.4 FLAVOR/FAT REPLACER INTERACTIONS The interactions between flavor compounds and fat replacers were studied by SchirleKeller et al. (1992) in model systems, each containing a different fat mimetic. The following fat mimetics were used: Simplesse® S-100, Simplesse® S-300, N-Oil II, Avicel® RC 591 (microcrystalline cellulose/sodium carboxymethyl cellulose) and Avicel® FD 100 (microcrystalline cellulose). All were used at concentrations of 10%, except for Avicel® RC 591, which, due to its high viscosity, was used at 2%. A 10% oil system was used as a control, and all model systems contained 0.5% of Tween 80, acting as an emulsifier, and 1% of a flavor cocktail comprising thirteen compounds; all samples were tempered at 37°C for 40 minutes prior to analysis. The relative vapor pressures of each compound in the aqueous solutions of the fat mimetics and of the controls were calculated from the headspace concentrations for each compound in relation to a water system where no interactions were taking place. The results obtained for Simplesse® S-300, Avicel® FD 100 and N-Oil II were very similar, showing minimal interactions with flavor compounds. On the other hand, Simplesse® S-100 and Avicel® RC 591 showed some interaction, with the Simplesse® S-100 showing especially strong interactions with aldehydes. No effects of increasing sample equilibration temperature were observed up to 70°C for Simplesse® S-100, thus indicating the very strong nature of the interactions taking place. The authors noted that the S-100 contained 1.72% of fat, and this may explain some of the interactions observed for the nonpolar flavor compounds. Contrary to the supposition of Dumont (1987), no changes in the relative vapor pressure of the flavor compounds over the nine-day period were observed. Schirle-Keller et al. (1992) concluded that although considerable change in the level of flavors used are needed when

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moving from a 10% oil-in-water emulsion to a fat-free (or almost fat-free) system containing fat mimetics, this would be less so when Simplesse® S-100 is the fat mimetic used. Another study investigated flavor interactions with fat replacers (Simplesse® S-100, Simplesse® S-300, Slendid® and Stellar™), and the effects of flavor/fat interactions in a system containing 0.5% Tween 80 and fat ranging from 0 to 20% (Schirle-Keller et al., 1994). This showed that the behavior of flavors was directly related to their oil solubility, and water soluble compounds (such as acetaldehyde) were largely unaffected by the presence or absence of oil. For the flavor cocktails used, the protein-based fat replacers showed more interactions with longer chain aldehydes (which would have higher fat solubility) than did carbohydrate-based fat replacers. It should be noted that, in this study, higher levels of Simplesse® ingredients were used than in the earlier work, and that the tempering of the samples was carried out at the higher temperature of 60°C. No indication was given in the paper that the required shearing was employed in the preparation of the Stellar™ and Slendid® model systems to achieve functionality (as recommended by the respective ingredient manufacturers). As in the previous paper (Schirle-Keller et al., 1992), the authors concluded that foods formulated with protein-based fat replacers should be more characteristic of fat-containing products in terms of flavor profile than would be the case of those containing other fat replacers; nonetheless, the need for reformulation would remain. 4.6.5 MASS TRANSFER INHIBITION AND FLAVOR RELEASE As indicated earlier, while a considerable amount of research has been devoted to partition phenomena, the issue of resistance to mass transfer as a factor in flavor release has not received the same level of attention. This is somewhat surprising, bearing in mind that availability (or accessibility), as a function of time, would be expected to play an important role in the overall flavor release equation. Considering the latter factor, the reason that the structure of the food would be expected to have an effect is that it would influence the breakdown of the matrix during mastication in the mouth. In turn, that could affect the convective transport of the volatiles to the olfactory epithelium. Although the importance of this issue is generally acknowledged (Overbosch et al., 1991), a certain amount of confusion exists which is related, at least partially, to methodological differences. A detailed discussion is beyond the scope of this chapter, but a few examples can be given. Numerous earlier studies examined the effects of mass transfer on flavor/taste perception by relating viscosity data to sensory perceptions. Cussler et al. (1979) established that perceived flavor ratings are proportional to the concentration of the flavor/taste compound and to the square root of the diffusion coefficient, whereby the latter is related to viscosity. Further studies by Kokini et al. (1982), using the same penetration model of mass transfer, showed that increasing tomato solids decreases the rate of transport of a sweetener (sucrose or fructose) to the surface of the tongue, resulting in a decrease of sweetness intensity. The results obtained by de Roos and Wolswinkel (1994) again showed that the higher viscosity of the liquid phase (1% carboxymethylcellulose solution) not only reduces the mass transport in the liquid phase, but also that in the gaseous phase. Furthermore, the authors demonstrated the effect of fat on flavor release in which an oil-in-water emulsion was formed containing 1% olive oil with carboxymethylcellulose acting as emulsion stabilizer. As a result, the viscosity of the system increased markedly, and a significantly higher flavor retention was observed for all flavor compounds investigated in comparison to that obtained from carboxymethylcellulose solutions without oil. These findings, therefore, highlight the extensive impact that a small level of oil addition makes on flavor release characteristics.

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While the studies mentioned above indicate the importance of diffusive mechanisms on sensory perceptions, Darling et al. (1986) proposed a different concept. On the basis of their study on flavor release from guar gum and sucrose solutions, as well as the modeling of those systems, they suggested that, on the one hand, partitioning behavior (which reflects an equilibrium condition) is unlikely to be obtained during the normal consumption conditions, and, on the other hand, diffusion processes are too slow to have any significant effect on in-mouth flavor perception. The authors postulate that it is the surface regeneration behavior that constitutes a significant physical factor which controls the availability of flavor for perception. The surface regeneration behavior will be a function of the rheological properties of the system and for solutions with noninteracting thickener molecules, the rate of flavor release will decrease with increased concentration (sucrose 0 to 60%; guar gum 0 to 0.2%). However, for solutions with interacting thickener molecules (e.g., guar gum at concentrations greater than 0.2%), the surface regeneration and flavor release increases with increases in the strength of the polymer network. Within the overall topic of flavor release mechanisms, the issue of comparative release from oil-in-water and water-in-oil emulsions is worth mentioning. Overbosch et al. (1991) concluded from their model that the release is independent of emulsion type. In other words, for the same flavor compound, the same oil and water phase, and the same volume fraction of oil, flavor release was found to be the same from oil-in-water as from water-in-oil emulsion. However, the above authors were not able to validate this point in the experimental work, where significantly greater release was obtained from an oilin-water emulsion. The different emulsifiers used for the two emulsions were considered to be responsible for the differences encountered, and for slowing down the diffusion of the flavor compound from water droplets into the gaseous phase. By comparison, Salvador et al. (1994) showed that the release of diacetyl was higher from an oil-in-water emulsion than from a water-in-oil emulsion (each containing the same oil volume fraction φ = 0.5), despite the fact that there were no differences in droplet size distribution, and that the same emulsifier was used in both emulsion systems in this study (sucrose stearate at 0.5% w/w). The results obtained led the authors to conclude that this is due to structural differences affecting mass transfer at the interfaces. It should be added that flavor release in this study was measured from a static system using headspace gas chromatography, and no sensory evaluations were carried out. Contrary to expectations, the results obtained by Barylko-Piekielna et al. (1994) in a study on perception of intensity of taste stimuli in oil-in-water and water-in-oil emulsions (again at φ = 0.5, but with sucrose stearate concentration at 1% w/v) showed no effects of emulsion type on taste intensity. Moreover, the differences in measured and perceived viscosity were found not to affect taste intensities studied, i.e., sweetness (sucrose at concentrations in the range 0.5 to 4.0%), saltiness (sodium chloride at concentrations in the range 0.25 to 1.0%), and sourness (citric acid at concentrations in the range 0.15 to 1.0%). The authors concluded that, on the one hand, the relatively small differences in measured viscosity between emulsion types could explain the lack of effect of viscosity on taste, and, on the other hand, inversion of the water-in-oil emulsion in the mouth (due to the effects of saliva and sample dilution during the process of mastication) could be the reason for the lack of differences in taste intensity observed for the two emulsion systems. Further research is required to confirm this hypothesis, but meanwhile the issue of the effect of type of emulsion on flavor release remains largely unresolved. However, while a certain level of phase separation or inversion of the water-in-oil system is a likely explanation, the extent to which this phenomenon may take place will depend on the physical properties and concentration of the emulsifier used, so that the answer should be sought through an examination of the behavior of the emulsifier at the water-oil interface in the respective types of emulsion.

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A few more general comments on flavor release mechanisms can be made. First, a comparison of static headspace data to that obtained from sensory studies is likely to lead to different conclusions since the process of flavor perception in the mouth is very dynamic. If the flavor is to be extracted into saliva, it would be expected that this would be more effective from a water-continuous system. The surface regeneration behavior of a system, pinpointed by Darling et al. (1986), would be expected to have an important role in flavor perception as volatiles need to be extracted into the air from thin layers formed in the mouth during the mastication process, and the concentration of the volatile compounds in these thin layers would determine the rate of release. It is also here that the emulsifier may have a retarding effect on flavor release. The same applies to taste perception where availability of the tastants to the receptors is of importance. From a methodological point of view, it could be argued that the chemical route for studying flavor release is more precise than sensory methods. However, while the latter may lack accuracy, and by definition it is a subjective method, it should be borne in mind that it is difficult to envisage that even future “mouth analogues” could fully imitate the dynamic in-mouth reality. In this context, however, training of the panel, understanding of the descriptors used, reproducibility of the results, points of reference, etc., are of particular significance. Overall, it seems reasonable to postulate that for any given system the three issues — i.e., partitioning behavior, diffusion behavior, and surface regeneration behavior — need to be carefully reviewed to determine the driving force for in-mouth flavor perception that is applicable to a particular product type. Moreover, the methodologies used to assess flavor release need to be carefully analyzed before any extrapolation of the results is undertaken. A better understanding of product structure, physical and chemical interactions at interfaces, and overall in-mouth changes will help to further our knowledge on flavor release phenomena in the context of fat reduction in foods.

REFERENCES Baines, Z. V. and Morris, E. R., Flavour/taste perception in thickened systems: The effect of guar gum above and below c*, Food Hydrocoll., 1 (3), 197, 1987. Baines, Z. V. and Morris, E. R., Effect of polysaccharide thickeners on organoleptic attributes, in Gums and Stabilisers for the Food Industry 4, Phillips, G. O., Wedlock, D. J., and Williams, P. A., Eds., Oxford University Press, Oxford, 1988, 193. Barylko-Piekielna, N., Martin, A., and Mela, D. J., Perception of taste and viscosity of oil-in-water and water-in-oil emulsions, J. Food Sci., 59 (6), 1318, 1994. Bavington, A. K., Clegg, S. M., and Jones, S. A., Physical and sensory characteristics of low-fat spreads, Leatherhead Food Res. Assoc. Res. Rep. No. 695, 1992. Bennett, C. J., Formulating low-fat foods with good taste, Cereal Foods World, (37), 429, 1992. Cain, F. W., Clark, A. H., Dunphy, P. J., Jones, M. G., Norton, I. T., and Ross-Murphy, S. B., European Patent Application EP 0298 561, 1989. Chen, W.-S. and Soucre, W. G., Edible fibrous serum milk protein/xanthan gum complexes, U.S. Patent 4,559,233, Dec. 17, 1985. Chen, W.-S., Wherry, G. A., Gaud, S. M., Miller, M. S., Kaiser, G.I., Balanced, E. A., Norman, R. G., Pair, C. C., Borwankar, R. P., Hellgeth, L. C., Strandholm, J. J., Hasenhuettl, G. L., Kerwin, P. J., Chen, C.-C., Kratchvil, J. F., Lloyd, W. Z., Eckhardt, G., De Vito, A. P., and Heth, A. A., Microfragmental ionic polysaccharide/protein complex dispersions, U.S. Patent 5,104,674, Apr. 14 1992. Clegg, S. M., Moore, A. K., and Jones, S. A., Role of aqueous phase stabilization in low-fat spreads, Leatherhead Food Res. Assoc. Res. Rep. No. 715 (1993). Cook, R., Finocchiaro, E. T., Shulam, M., and Mallee, F., A microparticulated zein/polysaccharide composite with fat-like properties, paper presented at the IBC Conference on Fat and Cholesterol Reduced Foods, Atlanta, March 14-16, 1991.

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Cussler, E. L., Kokini, J. L., Weinheimer, R. L., and Moskowitz, H. R., Food texture in the mouth, Food Technol., 33 (10), 89, 1979. Daget, N. and Joerg, M., Creamy perception II: In model soups, J. Texture Stud., 22, 169, 1991. Daget, N. M. T. and Vallis, L., Release of flavor from chocolates differing in fat composition and concentration, in Trends in Flavour Research, Maarse, H. and van der Heij, D. G., Eds., Elsevier Science B.V., Amsterdam, 1994, 39. Daget, N., Joerg, M., and Bourne, M., Creamy perception I: In model dessert creams, J. Texture Stud., 18, 367, 1987. Darling, D. F., Williams, D., and Yendle, P., Physico-chemical interactions involved in aroma transport processes from solution, in Interactions of Food Components, Birch, G. G. and Lindley, M. G., Eds., Elsevier Applied Science Publishers, London and New York, 1986, 165. de Roos, K. B. and Wolswinkel, K., Non-equilibrium partition model for predicting flavor release in the mouth, in Trends in Flavour Research, Maarse, H. and van der Heij, D. G., Eds., Elsevier Science B.V., Amsterdam, 1994, 15. Drewnowski, A., Fats and food acceptance in sensory, hedonic and attitudinal aspects, in Food Acceptance and Nutrition, Solms, J., Booth, D. A., Pangborn, R. M., and Raunhardt, O., Eds., Academic Press, New York and London, 1987, 217. Dumont, J. P., Flavour-protein interactions: a key to aroma persistence, in Flavour Science and Technology, Martens, M., Dalen, G. A., and Russwurm, H., Jr., Eds., John Wiley and Sons, Chichester, 1987, 143. Glicksman, M., Hydrocolloids and the search for the “oily grail,” Food Technol., 5 (10), 94, 1991. Iyenger, R. and Gross, A., Fat substitutes, in Biotechnology and Food Ingredients, Goldberg, I. and Williams, R., Eds., Van Nostrand Reinhold, New York, 1991, 287. Jones, S. A., Fat replacement, Proc. of 47th PMCA Conference, Hershey, Pennsylvania, April 19–21, 1993. Jowitt, R., The terminology of food texture, J. Texture Stud., 5, 351, 1974. Kasapis, S., Morris, E. R., and Norton, I. T., Physical properties of maltodextrin/gelatin systems, in Gums and Stabilizers for the Food Industry 6, Phillips, G. O., Williams, P. A., and Wedlock, D. J., Eds., Oxford University Press, Oxford, 1992, 419. Kokini, J. L., Kadane, J. B. and Cussler, E. L., Liquid texture perceived in the mouth, J. Texture Stud., 8, 195, 1977. Kokini, J. L., Bistany, K., Poole, M., and Stier, E., Use of mass transfer theory to predict viscositysweetness interactions of fructose and sucrose solutions containing tomato solids, J. Texture Stud., 13, 187, 1982. Kilcast, D., Crawford, B. A. and Foster, T. E., Sensory analysis of yellow fat spreads, Leatherhead Food Res. Assoc. Res. Rep. No. 683, 1991. Land, D. G., Some factors influencing the perception of flavor-contributing substances in food, in Progress in Flavour Research, Land, D. G. and Nursten, H. E., Eds., Applied Science Publishers, London, 1979, 53. Mela, D. J., Sensory assessment of fat content in fluid dairy products, Appetite, 10, 37, 1988. Mela, D. J., Langley, K. R. and Martin, A., Sensory assessment of fat content: Effect of emulsion and subject characteristics, Appetite, 22, 67, 1994. Miller, M. S., Proteins as fat substitutes, in Protein Functionality in Food Systems, Hetliarachchy, N. S. and Zeigler, G. R., Eds., Marcel Dekker, Inc., New York, 1994, 435. Muyldermans, G. and Vanhoegaerden, R., Gelatin-maltodextrin interactions and synergies, applications in 25% low-fat spreads, in Gums and Stabilizers for the Food Industry 6, Phillips, G. O., Williams, P. A. and Wedlock, D. J., Eds., Oxford University Press, Oxford, 1992, 429. O’Donnell, C. D., Global ingredient trends and advances, Prep. Foods, January, 46, 1994. Overbosch, P., Afterof, W. G. M., and Haring, P. G. M., Flavour release in the mouth, Food Reviews Int., 7(2), 137, 1991. Partel, P., Guerrero, A., Berjano, M., Muñoz, J., and Gallegos, C., Flow behaviour and stability of oilin-water emulsions stabilized by a sucrose palmitate, J. Texture Stud., 25(3) 311, 1994. Plug, H. and Haring, P., The role of ingredient-flavor interactions in the development of fat-free foods, Trends Food Sci. Technol., 4, 150, 1993. Pszczola, D. E., Carbohydrate-based ingredient performs like fat for use in a variety of food applications, Food Technol., 45, (8), 262, 1991. Reid, W. J. and Wragg, S., Investigation of a membrane interface for the analysis of organic compounds in breath by mass spectrometry, Leatherhead Food Res. Assoc. Res. Rep. (in press), 1995.

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Richardson, N. J., Booth, D. A., and Stanley, N. L., Effect of homogenization and fat content on oral perception of low and high viscosity model creams, J. Sensory Stud., 8, 133, 1993. Salvador, D., Bakker, J., Lanley, K. R., Potjewijd, R., Martin, A., and Elmore S., Flavour release of diacetyl from water, sunflower oil and emulsions in model systems, Food Qual. Pref., 5, 103, 1994. Schirle-Keller, J.-P., Chang, H. H., and Reineccius, G. A., Interaction of flavor compounds with Microparticluated proteins, J. Food Sci., 57 (6), 1448, 1992. Schirle-Keller, J.-P., Reineccius, G. A., and Hatchwell, L. C., Flavour interactions with fat replacers: Effect of oil level, J. Food Sci., 59 (4), 813, 1994. Shama, F. and Sherman, P., Identification of stimuli controlling the sensory evaluation of viscosity. II. Oral methods, J. Texture Stud., 4, 111, 1973. Singer, N. S. and Dunn, J. M., Protein microparticulation: The principle and the process, J. Am. Coll. Nutr., 9, 388, 1990. Shamil, S., Wyeth, L. J. and Kilcast, D., Flavour release and perception in reduced-fat foods, Leatherhead Food Res. Assoc. Res. Rep. No. 687, 1991. Solms, J., Interaction of non-volatile and volatile substances in food, in Interactions of Food Components, Birch, G. G. and Lindley, M. G., Eds., Elsevier Applied Science Publishers, London and New York, 1986, 189. Stark, L. E. and Gross, A. T., Hydrophobic protein microparticulates and preparation thereof, U.S. Patent 5,145,702, Sept. 8, 1992. Szczesniak, A. S., Classification of mouthfeel characteristics of beverages, in Food Texture and Rheology, Sherman, P., Ed., Academic Press, New York and London, 1979. Szczesniak, A. S., Brandf, M. A., and Friedman, H. H., Development of standard rating scales for mechanical parameters of texture and correlations between the objective and the sensory methods of texture evaluation, J. Food Sci., 28, 397, 1963. Tolstoguzov, V. B., Interactions of gelatin with polysaccharides, in Gums and Stabilisers for the Food Industry 2, Phillips, G. O., Williams, P. A., and Wedlock, D. J., Eds., Oxford University Press, Oxford, 1986, 157. Wood, F. W., An approach to understanding creaminess, Die Stärke, 26(4), 127, 1974. Wyeth, L. J. and Kilcast, D., Time intensity sensory analysis: An insight into flavor release, Food Technol. Int. Eur., 239, 1991. Zhao, J. and Whistler, R. L., Spherical aggregates of starch granules as flavor carriers, Food Technol., 48 (7), 104, 1994.

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Chapter

5

Legislative Implications of Fat Replacement Jane Smith CONTENTS 5.1 Introduction 5.2 Acceptability of Fat Replacers 5.3 Additives as Fat Replacers 5.4 Other Fat Replacers 5.5 Nutrition Labeling 5.6 Nutrition Claims References

5.1 INTRODUCTION With increasing interest in foods that can be used to reduce the total level of fat in the diet, as recommended by many experts including those who prepared the U.K. government’s “Health of the Nation” White Paper, the use of various ways and means to wholly or partially replace fat in a range of food products provides one of the major developmental areas for the food industry. The addition of compounds which act directly as fat replacers, be they acting either as fat mimetics or fat substitutes, have to take into account existing legislative requirements for the use of such products. In addition, changes are needed to product labeling in order to provide the necessary information concerning the composition and properties of the food to consumers so that they may obtain an informative description as to the nature of the product and not be misled in any way as to its nature, substance, or quality. Manufacturers wishing to use such fat replacers must therefore be aware not only of legislative developments concerning direct addition of the compound in which they are interested but also how the food in which the compound is to be used must be labeled.

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Manufacturers find that the use of nutrition claims often provides a marketing advantage in consumers eyes; developments in nutrition labeling and claims requirements must therefore be considered. Within Europe, much of the legislation on nutrition labeling results from developments at European Community (EC) level, with the aim of harmonization in this respect throughout the European Union. The situation on claims is more variable at present. Provisions in the U.S. are quite different from those in Europe, and may be different again in other major export markets. In this chapter, the legal aspects of fat replacement in two principal regions, Europe and the U.S., are described and compared.

5.2 ACCEPTABILITY OF FAT REPLACERS The most fundamental issue that a manufacturer wishing to use a fat replacer must take into account is whether or not the particular fat replacer is permitted for food use. The wide range of potential fat replacers on the market means that legislative controls may differ, depending on the nature of the component concerned and the food product in which they are to be used. Account also has to be taken of any existing minimum compositional requirements for the food in question. Although the current trend in food legislation is away from so-called vertical or compositional requirements and toward more informative labeling, there may still be compositional aspects that need to be taken into account; for example, the recent legislation on the composition and labeling of lowfat spreads at European Community level. Further criteria that need to be taken into account include the general classification of fat replacers. Differentiation between those compounds permitted generally as food ingredients and those classified as food additives is significant here. If the potential fat replacer is already widely used as a food ingredient, then its use is likely to be generally acceptable, unless there are any compositional regulations that preclude such use and provided the compound meets the necessary quality and safety requirements for food use, such as those laid down under the 1990 Food Safety Act in the U.K. Starches, including those that have been modified by physical or enzymatic means, are generally considered as food ingredients and so permitted widely for food use. In contrast, chemically modified starches tend to be classified as additives along with other compounds of interest, including celluloses, gums, pectin, bulking aids, emulsifiers, and stabilizers. The future direction of acceptability of these compounds, certainly within the European Union, is covered by horizontal legislation on use of food additives now in place. When these compounds are to be used at additive levels in a food the situation is clear-cut; any maximum limits specified will have to be adhered to for additive purposes. However, if use is at higher levels than those generally accepted as additive levels, approval may be required from the regulatory authorities. Where Good Manufacturing Practice (GMP) is the accepted level, this eliminates the problem of exceeding specified limits. The situation with polydextrose illustrates the different way in which compounds can be regulated, as illustrated in Table 5.1. Table 5.1

Current Legislative Status of Polydextrose

Country

Status

Permitted level of use

European Union Directive United Kingdom Sweden U.S.

Additive Additive Additive Additive

Australia Japan

Additive Ingredient

Quantum satis (QS) GMP unless restricted by standard of composition Maximum limit set by positive list depending on food GMP in specific foods only including bakery products, fillings, puddings, candy Specific limit may be set by food standard None set

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In certain cases, a manufacturer may wish to use a compound that has not previously been used as a food component, or which is manufactured by a new or novel process. In such cases, specific approval for the use of such a compound is usually required; this can take considerable time. The criteria for the approval of food additives have been specified by the EC framework additives directive; such criteria may need to be taken into account.

5.3 ADDITIVES AS FAT REPLACERS A number of compounds that can be used as fat replacers in foods are classified as additives and so are controlled by appropriate additives legislation. One of the most notable developments in food legislation in recent years is progress toward harmonized additives legislation at European Union level. Certain of the European countries not currently members of the Union but linked via economic agreement are taking steps to amend their legislation to bring it into line with Community legislation and this trend is set to continue. Additives such as gums, other hydrocolloids, bulking aids, emulsifiers, stabilizers, and celluloses are controlled for food use by Council Directive 95/2/EC on food additives other than colors or sweeteners. This directive establishes second order controls for named additives, i.e., not only is a positive list of additives established but also the foods in which they can be used and maximum permitted levels of use. Once implemented by the Member States, this aims to ensure that products can be traded freely throughout the Community in accordance with the Treaty of Rome with respect to their additives content. This Directive, due to its complexity, was under discussion for some time before final agreement was reached. It is divided into a number of sections; those of relevance here relate to additives generally permitted for food use (except for specified and unprocessed foods) (Appendix I) and other permitted food additives (Appendix IV). Appendix I includes compounds such as lecithins, alginates, carrageenan, gums (including gellan and tara gum), glycerol, pectins, celluloses, various esters, polydextrose, and specified chemically modified starches. These additives may therefore be used generally to quantum satis (QS), i.e., no maximum level is specified, but additives must be used in accordance with good manufacturing practice (GMP) at a level not higher than that intended to achieve the desired purpose and provided that they do not mislead the consumer. The use of these compounds as fat replacers would therefore be acceptable, provided the conditions of quantum satis were met. As all additives having a technological function in the final food have to be declared on the label by specified category name where laid down (if appropriate) and/or by specific name, account would have to be taken as to the function of the additive in the food for labeling purposes. Labeling of additives in foods is controlled by EC Directive 79/112/EEC; a recent amendment to this (Commission Directive 93/102/EEC) extends the list of category names to include bulking agent as well as retaining existing categories such as stabilizer, thickener, emulsifier. Appendix IV details permitted uses for additives including emulsifiers, karaya gum, and polyhydric alcohols. For example, sorbitan esters may be used in fat emulsions to a total maximum of 10 g/kg and karaya gum to the same maximum level in emulsified sauces. Usage of these additives will therefore be restricted although provision is made for a review of the Directive 5 years from adoption with a view to modification where necessary. Manufacturers will meanwhile have to comply with what is already established. One of the problems for those in the food industry responsible for ensuring the legality of their products is keeping abreast of developments and possible changes to documents such as this one in order to be fully aware of the impact on their product.

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In the U.S. those additives permitted for direct food use are termed direct additives. The standard of identity for particular food products controls the use of additives in these products; for so-called nonstandardized foods, the conditions of use for specific additives states whether the additive in question can be used for foods generally, or whether use of an additive is restricted to particular foods only. These additives are classified by legal status and may have permanent food additive status, be prior sanctioned, GRAS (generally recognized as safe), or permitted on an interim basis. For GRAS substances, maximum usage limits may be set or, alternatively, they may be “generally recognised as safe when used in accordance with Good Manufacturing Practice.” To illustrate how these additives are regulated in the U.S., polydextrose (see also Chapter 11) is permitted to GMP as a bulking agent, formulation aid, humectant, or a texturizer in specified foods. Guar gum is classified as GRAS, but is only permitted in foods as authorized and to the maximum limits established. Other gums tend to be classified in a similar way. Sodium alginate is also GRAS and permitted in specified foods to the maximum limits established, but is also permitted in foods generally (unless restricted by a standard of composition) to the maximum specified limit. If usage is desired at a higher level than that authorized, approval from the FDA is likely to be required.

5.4 OTHER FAT REPLACERS Not all fat replacers can be classified as food additives as currently defined by the Directive 89/107/EEC on food additives (the so-called framework additives directive). A food additive is defined as a substance not normally consumed as a food in itself and not normally used as a characteristic ingredient of the food whether or not it has nutritive value, the intentional addition of which to food for a technological purpose in the manufacture, processing, preparation, treatment, packaging, transport, or storage of such food results, or may be reasonably expected to result, in it or its byproducts becoming directly or indirectly a component of such foods. Some fat replacers may be based on food components, for example, proteins (see also Chapter 8); others may be totally new compounds, for example, some of the synthetic fat substitutes that are currently under development (see Chapter 13). Regulatory approval for such compounds can be a long, time-consuming process as well as extremely expensive. Currently in European countries, the national authorities need to be consulted in order to obtain approval. Such compounds are generally known as novel ingredients and proposed EC legislation on approval of such novel ingredients is nearing completion in order to harmonize approval procedures throughout the Community. It is significant that, when finalized, such legislation will be in the form of a Regulation as opposed to a Directive, and therefore will be binding on all the individual Member States from the date of publication; labeling of foods containing these novel ingredients is currently the key issue where agreement has yet to be reached. Discussion on this draft has focused on the scope of such a proposal, i.e., exactly what type of compounds would be covered by it, the procedures to be followed in evaluating a novel ingredient, and arrangements for labeling such an ingredient in the final food. It is intended at this stage that novel food additives would not be caught by the proposal as provision is already made for these under the general additives framework directive 89/107/EEC. The current draft considers novel food ingredients as those which have not yet been used for human consumption to a significant degree within the European Union and which fall under one of the following categories.

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1. Ingredients containing or consisting of genetically modified organisms 2. Ingredients produced from genetically modified organisms, other than those where no significant change in composition, nutritional value, metabolism, level of undesirable susbstances, or intended use has resulted when compared to a standard product 3. Food ingredients with a new or intentionally modified primary molecular structure 4. Ingredients consisting of or isolated from microbes, fungi, or algae and single- or multi-cell proteins derived therefrom 5. Food ingredients to which have been applied a process not currently used in commercial food production and significant changes in the composition or the structure of the endproduct result, affecting its nutritional value, digestibility, metabolism, or level of undesirable substances in the food

Under the proposal, in order to be placed on the market, such food ingredients must be safe for the consumer, when consumed at the intended level of use, must not mislead the consumer, and must not differ from similar foods or food ingredients that they replace in the diet in such a way that their normal consumption would be nutritionally disadvantageous for the consumer. Such an aspect is particularly relevent for fat replacers; not only is it the calorific and textural aspects of fat addition to foods that are being replaced but also nutritional aspects such as the content of fat-soluble vitamins. Separate vitaminization may therefore be required; again, this would have to be carried out in accordance with the legislation of the relevant country. In some cases, the addition of vitamins renders a food a dietetic product. In the U.K., a Panel on Novel Foods of the Committee on Medical Aspects of Food Policy (COMA) has recently produced a report entitled “The Nutritional Assessment of Novel Foods and Processes,” which details general principles and criteria as well as specific nutritional criteria to be used in the consideration of novel foods and food processes referred to COMA. Currently in the U.K., it is the Advisory Committee on Novel Foods and Processes (ACNFP) who review applications for use of novel food ingredients. Specific approval is given in each case where deemed appropriate, together with any conditions of use. The Food Advisory Committee (FAC) (a group of experts from the food industry and related professions who advise the Minister of Agriculture, Fisheries, and Food) also review continuing technological developments within the food industry and advise accordingly. With novel food additives, existing European Community legislation has to be taken into account; the U.K. can no longer act unilaterally in terms of acceptability of specific food additives. With Simplesse®, a protein-derived fat mimetic derived from dairy and egg protein (see Chapter 11), the Advisory Committee on Novel Foods and Processes considered that Simplesse® was unlikely to give rise to any particular safety concerns and so could be used in foods. So far it has been incorporated mainly into dairy products; its use is being kept under review, with any possible future regulatory action depending on how widely it is introduced into food products in this country. A further committee, the Committee on Medical Aspects of Food Policy (COMA) is also keeping the uptake of Simplesse® by the food industry under review. Two of the issues that the Food Advisory Committee is considering are the possible overlap between novel foods and additives and the role of fat replacers generally. In the U.S., approval has to be given by the Food and Drug Administration (FDA) for the use in food with any ingredient that would be classified as a novel ingredient. Currently there is no specific legislation on novel foods or ingredients in the manner that is being prepared in Europe. However, the importance of regulatory approval procedures in the U.S. cannot be underestimated as these often have significant bearing on approvals elsewhere in the world, as the situation with Simplesse® illustrates. Simplesse® is classified

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as GRAS and may be used in frozen-type dessert products (except to replace the milk fat required by standards of composition) to good manufacturing practice. Specific labeling requirements for the ingredient are detailed, including the requirement to declare the source of the protein and a list of the ingredients of the microparticulated protein product. It was only following U.S. approval for Simplesse® that the European industry began to take a serious interest in the product (see also Chapter 11). The current situation is somewhat different when low-calorie fats and synthetic fat substitutes are considered (see also Chapter 13). Due to their nature, separate approvals for each compound are required before use in foods would be permitted. Currently, Caprenin is pending approval from the FDA for direct food use. Caprenin and other recent developments in the EC-proposed regulation on novel foods and novel food ingredients were scheduled for discussion at recent meetings of the ACNFP in the U.K. The other synthetic fat substitute that is most widely known at this stage is olestra and this is considered generally to be at the stage nearest approval. From a U.K. point of view, assessment has been ongoing since 1987, when the FAC considered a case of need for olestra and subsequently consulted the Committee on Toxicity (COT) on its safety in use. The nutritional implications of olestra’s use in the diet have also been considered by COMA; its advice was passed onto the FAC who will be evaluating further data. It is possible that it may be looked at under additives legislation, which would then involve consultation and communication with Brussels.

5.5 NUTRITION LABELING Many food products on the market contain details of nutritional characteristics of the food in question; it is likely that foods containing fat replacers will carry such information to emphasize their properties. Nutrition labeling requirements in European Union countries have been harmonized by means of EC Directive 90/496/EEC on nutrition labeling. All of the Member States have now implemented the appropriate legislation into their national laws, as the Directive came into force on 1 October 1993; the U.K. introduced its implementing regulations, the 1994 Food Labeling (Amendment) Regulations, in March 1994. Full implementation of the Directive took place on March 1, 1995. The Directive concerns nutrition labeling of foods to be delivered as such to the ultimate consumer and to those foods destined for mass catering establishments. Exempted are foods which are not prepacked and which are sold to the ultimate consumer at a catering establishment. Although the increase in food being consumed from catering outlets would ideally mean nutrition labeling being given in this case, the problems of declaring such information have yet to be overcome. Essentially, nutrition labeling on foods will remain voluntary unless a nutrition claim is made for that food. As many foods containing fat replacers are likely to make such claims concerning their low- or reduced-fat content, provisions relating to nutrition labeling will be applicable to them. If nutrition labeling is given, it must be in the specified format, namely either energy, protein, carbohydrate, and fat (so-called Group I or “Big Four” format) or energy, protein, carbohydrate, sugars, fat, saturates, sodium, and fiber (so-called Group II format). A number of optional extras including polyunsaturates, monounsaturates, and cholesterol are listed and may be given. Where a nutrition claim is made for saturates, then Group II labeling must be given; a claim for any of the additional extras triggers declaration of these in terms of nutrition labeling. Declaration is per 100 g or ml of the product, as appropriate, and may be given in addition per serving or per portion quantified on the label where desired. Energy values to be declared are calculated using specified conversion factors and the manner in which the information is to be set out on the label is fully defined.

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In contrast, the U.S. Nutrition Labeling and Education Act amended the Federal Food, Drug and Cosmetic Act to require the mandatory nutrition labeling of most foods from May 8, 1994. Nutrition information must be declared on the information panel and must include information on levels of calories, calories from fat, total fat, saturated fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, protein, vitamins, and minerals. Information about other components such as polyunsaturates, potassium, soluble and insoluble fiber can be given voluntarily unless a claim is made. Detailed provisions concerning presentation of information are specified in order to make the information readily apparent to consumers. Requirements for U.S. nutrition labeling are therefore significantly different from those required by the EC Directive and need to be considered separately from European requirements. Table 5.2 illustrates the differences in format (note that the examples used are not of the same product). Table 5.2

Examples of Nutrition Labeling in U.K. and U.S.

United Kingdom:

per 100g

Energy

Per serving with specified complementary food

1495 kJ 350 kcal 9.9 g 73.9 g 9.3 g 1.9 g 0.4 8.4 g 0.6 g

Protein Carbohydrate of which sugars Fat of which saturates Fiber Sodium

930 kJ 220 kcal 8.7 g 39.3 g 10.1 g 2.9 g 1.5 g 3.8 g 0.3 g

United States: Serving size 3.5 oz Servings per container about 2.5 Amount per serving: Calories 310 Calories from fat 80 Total fat Saturated fat Cholesterol Sodium Total carbohydrate Dietary fiber Sugars Protein Vitamin A Calcium Vitamin C Iron

9g 5g 40 mg 310 mg 41 g 3g 1g 16 g

% daily value 14% 25% 13% 13% 14% 12%

10% 25% 0 10%

5.6 NUTRITION CLAIMS Certain Member States in the European Union already have, or would like to have, national provisions, be they regulations or guidelines, controlling the use of nutrition claims on food labels, for example “low fat,” “reduced fat,” or “fat free.” The use of such claims is of particular relevance to those food products containing fat replacers. Development

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of harmonized provisions for the use of such claims has been underway for some time, despite difficulties in agreeing in formats and detail between the various Member States. It is seen as important and in the interests of consumers that claims relating to foods which by their nature have special effects, characteristics, or properties linked to their nutritional value or composition be worded so that they are not misleading or liable to mislead. Under the latest draft document in circulation, a claim is defined as any reference, message, or interpretation, whatever the means or form of transmission, stating, implying, or suggesting that a food has particular characteristics, properties, or effects linked to nature, composition, nutritional value, method of production and processing, or any other quality. It is possible at this stage that trademarks may also be included, although this has caused some controversy. Earlier drafts included specific provisions for claims. For example, a claim for “low,” “weak,” or “poor” would only be authorized for foods with a reduced fat content of at least 50% from a standard product, except where specific criteria have been established. For energy, a requirement for the product to have less than 40 kcal/100 g product is given; this is in line with existing U.K. legislation under the 1984 Food Labeling Regulations. For fat, less than 3 g/100 g product was specified. Additional criteria for saturates and cholesterol were also established. A reduction of at least 25% from a standard product would be required to use the term “reduced,” together with any other specific conditions. For fat, more than 3 g/100 g product is required and for energy more than 40 kcal/100 g product, in order to differentiate between “reduced” and “low” products. Detailed conditions were also given for saturates and cholesterol. The term “without” would be considered acceptable under the draft where the amount of the element is too small to be of nutritional or physiological significance or to be reliably quantified by a standard method of analysis, again taking into account any specific requirements. For fat, such a requirement is that the content must be less than 0.15 g/100 g product; for cholesterol, the stringent requirements specified were less than 5 mg/100 g product, less than 1.5 g saturates/100 g product, and less than 10% of energy generated by saturates. Provision was also made under the earlier drafts for use of such a claim as “contains x% less;” such a claim could well be relevent to a manufacturer of products containing fat replacements. Use of the term “light” in food labeling was also covered; this is particularly attractive for products that have been produced with a lower energy or fat content in relation to standard products. Reference was made to the use of this term in conjunction with specifications already discussed; for example to be described as “light” in respect of energy content, a product must comply with provisions stated for reduced or low energy and to be described as “light” in respect of other components, appropriate provisions relating to energy and the particular nutrient in question must be met. Final agreement on this document had yet to be reached at the time of writing; a consultation process with interested parties will be carried out before a final draft is published. It is looking increasingly likely that the more specific criteria will not remain in future drafts and that the document will be general in nature, although the relevant detail is of interest from a comparative point of view. The U.S. FDA has also produced regulations on the use of specific nutrient content claims on food labels covering both expressed claims (direct statements about the level or range of nutrients in a food) and implied claims (those suggesting nutrients are present/absent in a certain amount or those suggesting that, because of their nutrient content, foods may be useful in being healthy and which are made in conjunction with an explicit claim or statement, e.g., “healthy,” “contains 3 g of fat”). “Free” and “low” claims before the name of the food can only be used for foods that have been specially

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processed, altered, reformulated, or formulated to lower or not include a nutrient in the food. Of particular interest for manufacturers of products containing fat replacers are reduced and low calorie and fat claims. Reference can be made to low calorie where the food has a reference amount (which varies depending on the food type) greater than 30 g or 2 tablespoons and can only provide a maximum of 40 calories per reference amount, or where the reference amount is 30 g or 2 tablespoons or less and must not provide more that 40 calories per reference amount and per 50 g. Relative claims for reduced calorie can be given where at least 25% fewer calories are present. Parallel requirements are established for low- and reduced-fat claims as above. A fat-free claim can be given where the food contains less than 0.5 g fat per reference amount and per labeled serving, and where the food contains no added ingredient that is fat unless indicated below the ingredients list with an asterisk and to the effect of “adds a trivial amount of fat.” It can be seen that these regulations are complex in nature and differ significantly from those proposed in Europe. A further development in the U.S. which has impacted significantly on the use of fat replacers has been the amendment to food standards to prescribe a definition and standard of identity for foods named by using a nutrient content claim as defined (e.g., fat free, low calorie, or light) in conjunction with a standardized traditional name (e.g., reducedfat sour cream). The modified product must not be nutritionally inferior to the standardized food and performance characteristics must be similar to the standardised product; any significant difference that limits the use of the food must be given on the label, e.g., “not recommended for cooking.” At least one of the principal functions of the standardised product must be performed substantially as well by the modified product. Labeling declarations also require the presence of ingredients not found in the standardized foods to be stated. The relevant legislation that those wishing to use fat replacers must take into account concerns not just acceptability of addition of the compounds but also labeling aspects in order that the consumer is not misled. Currently some of the appropriate legislation is still in a state of flux; final adoption of Community legislation on additives other than colors and sweeteners has helped, and that on novel foods and nutrition claims will clarify the situation for the food manufacturer. Developments in the U.S. will be closely watched by the food industry in Europe, particularly in respect to new compound approvals, further technological developments, and further amendments in labeling legislation. It is essential that the legislation over the next few years is able to keep pace with the increase in the use of the different types of fat replacers with potential use in the food industry.

REFERENCES Commission Directive 93/102/EEC of 16 November 1993 amending Directive 79/112/EEC on the approximation of the laws of the Member States relating to the labeling presentation and advertising of foodstuffs for sale to the ultimate consumer. Off. J. Euro. Commun., 36(L291), 14, 1993. Council Directive of 18 December 1978 on the approximation of the laws of the Member States relating to the labeling, presentation and advertising of foodstuffs for sale to the ultimate consumer. Off. J. Euro. Commun., 22(L33), 1, 1979. Council Directive of 21 December 1988 on the approximation of the laws of the Member States concerning food additives authorised for use in foodstuffs intended for human consumption. Off. J. Euro. Commun., 32(L40), 27, 1989. Council Directive of 24/9/90 on Nutrition Labeling for Foods. Off. J. Euro. Commun., 33(L276), 40, 1990. Council Regulation (EC) No 2991/94 of 5 December 1994 laying down standards for spreadable fats Off. J. Euro. Commun., 37(L316), 2, 1994.

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Department of Health Report on Health and Social Subjects 44 — The Nutritional Assessment of Novel Foods and Processes, HMSO, London, 1993. Document 6874/94 on Amended Proposal for a European Parliament and Council Regulation (EC) on novel foods and novel food ingredients, Brussels, May, 1994. Document SPA/62/REV3. Orig. FR., Consumer Policy Service Unit 4 — Foodstuffs Commission of the European Communities, Brussels, July, 1993. European Parliament and Council Directive 95/2/EC of 20 February 1995 on food additives other than colours and sweeteners. Off. J. Euro. Commun., 38(L61), 1, 1995. Federal Register, 58(3), 2431, 1993. Food Labeling (Amendment) Regulations 1994, SI 1994 No. 804. HMSO, London. Food Legislation Topics No. 2 A Guide to U.S. Nutritional Labeling and Claims, Lisa J. Skelton. The British Food Manufacturing Industries Research Association Leatherhead, 1993. Food Safety Act 1990 — HMSO, London. Health of the Nation White Paper — HMSO, London, 1992. U.S. Code of Federal Regulations, Title 184.1498.

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Part

II

Fat Replacers and Their Properties

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Chapter

6A

Starch-Derived Fat Mimetics: Maltodextrins Sibel Roller CONTENTS 6A.1 6A.2 6A.3 6A.4 6A.5 6A.6

Introduction and Historical Perspective Production Processes and Patents Chemical Composition Physical and Functional Properties Interactions with Other Food Ingredients Applications 6A.6.1 Low-Fat Spreads 6A.6.2 Other Food Applications 6A.7 Nutritional, Toxicological, and Legislative Aspects 6A.8 Future Prospects References

6A.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Starch is one of the most abundant carbohydrates distributed worldwide in green plants, where it is accumulated as a reserve material in the form of microscopic granules. Starch has played an important nutritional role in man’s diet since the beginnings of agriculture and, more recently, has become a major industrial raw material used widely in food, paper, board, textile, and pharmaceutical applications. It has been estimated that by the year 2000 more than 900 million metric tonnes of starch will be produced worldwide from cereals alone (Zobel, 1992). With a raw material price that is in the region of tens of U.S. cents per kg, it is not surprising that ingredient manufacturerers have sought to upgrade the properties of starch in order to add to its value and to extend its applications.

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Starches from corn, potato, wheat, rice, tapioca (also known as cassava or yucca), sago palm, barley, sorghum, and other grains and roots serve as raw materials for the making of hydrolysate products around the world. Most of these hydrolysate products are in the form of sugar syrups, used in the food industry as sweetening agents. It has been estimated that about 70% of the world production of corn starch is converted into glucose-containing sweeteners (Schenk and Hebeda, 1992). However, in this chapter, only those starches that have been degraded to a very limited extent for the specific purpose of preparing ingredients useful in fat replacement are discussed. The term “maltodextrin” was first used very broadly in the early 1950s to describe oligosaccharides consisting of α-1,4-linked glucose units and including mixtures of maltose, maltotriose, maltotetraose, maltopentaose, and higher oligosaccharides (Alexander, 1992). By 1957, a narrower definition was published by the American Corn Industries Research Foundation in which “maltodextrin” was defined as the product obtained by the incomplete hydrolysis of cornstarch and containing 13 to 27% reducing sugars, calculated as anhydrous dextrose and expressed on a total solids basis (Hoover, 1957). In 1983, the U.S. Food and Drug Administration (FDA) issued regulations defining maltodextrins as nonsweet, nutritive saccharide polymers consisting of D-glucose units linked primarily by a-1,4 bonds with a dextrose equivalent (DE) of less than 20. The regulations further stipulated that maltodextrins were prepared by partial hydrolysis of cornstarch using acids and/or enzymes, thereby apparently excluding similar materials from other starch sources such as potato or tapioca. Currently, the term maltodextrin is used widely in the general literature to describe enzymically-prepared, partially-hydrolyzed starches with a DE below 20 from any botanical source. In this chapter, discussion is focused on a specific group of maltodextrins, i.e., the low-DE maltodextrins, as the DE range of 1 to 10 has been found particularly useful in fat replacement. “Starch hydrolysis product” is a term generally used very broadly to describe all oligosaccharide and monosaccharide mixtures obtained by acid or enzymic degradation of starch. By this definition, maltodextrins and high-fructose corn syrups are both starch hydrolysis products. However, in the 1970s a series of papers and patents from the former East Germany (discussed in more detail below) describing starch hydrolysis products (SHPs) with DEs of 5 to 8 with unusual functional properties useful in fat replacement were published (Richter et al., 1976a and b). Since then, the term SHP has also been used in a narrower sense to describe hydrolysates degraded to a very limited extent or to a DE below 10. To avoid confusion, the term starch hydrolysis product is used in this chapter only in its broadest sense. The first maltodextrin to be commercialized was an acid hydrolyzed dent corn starch with a DE of 15 produced in 1959 by the American Maize Products Company (Amaizo). Other companies, including CPC International and the Grain Processing Corporation (GPC), were also prominent in the early development of maltodextrins. The potential use of α-amylase in the preparation of maltodextrins was investigated in the 1960s by researchers at CPC International (Alexander, 1992). The early products were marketed primarily as carriers and bulking agents for use in dry food mixes. It was not until the mid-1970s that it was first suggested by a group of scientists working at the former East German Academy of Sciences that low-DE maltodextrins prepared from potato starch could be used as fat replacers in foods (Richter et al., 1976a and b). The German scientists have since patented their process (discussed in more detail below) and a factory (VEB Stärkefabrik “Kyritz”) manufacturing low-DE maltodextrins for low-fat dressings and ice cream was in operation in East Germany from 1980 until mid-1990 (Schierbaum, 1991). Meanwhile, in the last 10 years, low-DE maltodextrins developed specifically for fat replacement have been launched by most of the major starch-producing companies, including, for example, the Paselli range (see Chapter 6B) from potato starch (Avebe)

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and Instant N-Oil from tapioca starch (National Starch & Chemical Corporation). Some examples of commercially available low-DE maltodextrins developed for fat replacement and a selection of their properties are given in Table 6A.1. Fat replacers in which maltodextrins form the bulk of the material but which contain smaller amounts of other carbohydrates have also been introduced to the market recently. For example, Oatrim was developed at the Northern Regional Research Center in the U.S. by George E. Inglett and is produced from oat bran or oat flour using α-amylase. This material differs from other maltodextrins in that it contains up to 5.5% soluble β glucan. Oatrim is now licensed by Con-Agra Speciality Grain Products and is marketed by A.E. Staley as TrimChoice® (Duxbury, 1993; Inglett, 1990 and 1991; Inglett and Grisamore, 1991). For a complete list of starch-derived fat replacers and their manufacturers/developers, refer to the Appendix.

6A.2 PRODUCTION PROCESSES AND PATENTS Older methods of generating maltodextrins have relied heavily on heat and acid treatment of starch. While effective, these methods sometimes produced undesirable by-products and off-flavors under harsh reaction conditions. Enzymes catalyze reactions under mild conditions of temperature and pH and have the added advantage of specificity of reaction with fewer by-products (Amylase Research Society of Japan, 1988). The current low cost of starch-degrading enzymes means that enzyme recovery from the reaction mix is unnecessary and their breakdown products (amino acids and peptides) are generally equivalent to other proteinaceous material found in starch and therefore require no special refining steps (Alexander, 1992). The industrial manufacture of maltodextrins is today based on variations of two principal processes. In the first, single-stage process, gelatinization (solubilization) of the starch (usually at a concentration of around 30%) is combined with acid or enzyme treatment at high temperatures (e.g., >105°C for conversion of dent cornstarch using acid, and 82 to 105°C for conversion of waxy cornstarch using thermostable bacterial enzymes). Maltodextrins such as Lo-Dex from Amaizo and Star Dri from A.E. Staley are produced using single-stage processing. In the second, dual-stage process, the starch is first gelatinized at 105°C in the presence of either acid or enzyme to a DE of <3, followed by jet-cooking at 110 to 180°C to ensure the complete gelatinization of the starch. Subsequently, the starch slurry is cooled to 82 to 105°C and treated with a fresh batch of bacterial α-amylase until the desired degree of hydrolysis is reached. The Maltrin® range of products manufactured by GPC and the Paselli range from Avebe (see Chapter 6B) are made using the dual-stage process. In both the single-stage and dualstage processes, the hydrolysis reaction is terminated by either pH adjustment or heat deactivation, followed by refining and spray-drying (Alexander, 1992). Numerous patents covering the processing of maltodextrins were published in the 1970s and 1980s by many of the major starch-processing companies. Careful reading of even a small selection of these reveals remarkable similarities between them: they are essentially further refinements and improvements of the same process, described in general terms in the paragraph above. For example, Lenchin and colleagues of the National Starch & Chemical Corporation (1985) published a patent covering the hydrolysis of tapioca, corn, and potato starches, using an α-amylase of unspecified source, to a DE of less than 5. Tapioca starch was identified as the preferred starch source. Temperature control during heating of the starch dispersion was reported in the patent to be unnecessary. It is possible that the industrial process used by National Starch & Chemical to make their product N-Oil is based on this patented invention. Another example is given by the patent assigned to GPC in which potato, sorghum, tapioca, wheat, rice, and

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Table 6A.1 Examples of Starch-Derived Fat Replacers (DE Below 10) and Some of Their Properties Parent starch

Product name

Manufacturer

Corn/Maize

Amalean I and II (instant) Lycadex® 200 Maltrin® M040, M050, M100, M150, M180, M520 OptaGrade Stellar™ Lean Bind, N-Lite® L Lo-Dex N-Lite® B N-Lite® D, N-Lite® LP Sta-Slim™ 171 C*Pur 01906 Lycadex® 100 Paselli SA2 (see also Chapter 6B) Sta-Slim™ 142 and 143 N-Oil, Instant N-Oil Slenderlean™ Sta-Slim™ 150-151

American Maize Products Co.

Waxy Maize

Potato

Tapioca

Roquette Frères Grain Processing Corp.

Opta Food Ingredients A.E. Staley Manufacturing Co. National Starch & Chemical Co. American Maize Products Co. National Starch & Chemical Co. National Starch & Chemical Co. A.E. Staley Manufacturing Co. Cerestar (Gruppo Feruzzi) Roquette Frères Avebe A.E. Staley Manufacturing Co. National Starch & Chemical Co. National Starch & Chemical Co. A.E. Staley Manufacturing Co.

Method of production

MW (kDa)

Label designation

600

Food starch — modified

Enzymic Dual-stage enzymic and/or acid

20

Maltodextrin Maltodextrin

Acid and shear

<20

Single-stage acid/enzyme

Enzymic Enzymic Dual-stage enzymic

150 and 180; 50–180 and 6 1–2,000 120; 290; 177 1,000

Cornstarch Food starch — modified Food starch — modified Maltodextrin Food-grade maltodextrin Modified food starch Food starch — modified Maltodextrin Maltodextrin Food starch — modified Tapioca dextrin/maltodextrin Food starch — modified Food starch — modified

Compiled from Braudo et al., 1979; Haenel and Schierbaum, 1980; Harris and Day, 1993; Lucca and Tepper, 1994; Roller and Dea, 1995; Setzer and Racette, 1992; Yackel and Cox, 1991; manufacturers’ literature.

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sago are used as botanical sources of the starch, with corn identified as the preferred source (Morehouse and Sander, 1987). However, it is notable that the GPC patent is said to have been withdrawn recently (Harkema, 1994). In 1976, Richter and his colleagues in the former East Germany patented a process that was different from the common industrial processes in that it was based on enzymic treatment of starch that had not been fully gelatinized. This approach was reported to give low-DE maltodextrins with unique properties particularly suited to fat replacement (Richter et al., 1976a and b). According to Richter’s patent, root and bulb starches, particularly potato starch, were dispersed at concentrations between 10 and 30% with bacterial α-amylase and heated to a temperature that was 1 to 4°C below the temperature at which the swelling of the starch granules commenced (i.e., the gelatinization temperature, which is in the region of 58° to 65°C for potato starch). The mixture was held at a temperature of 55 to 60°C for 5 to 30 minutes or until the DE reached a value between 5 and 8. The enzyme was inactivated by raising the temperature of the mix to 90 to 100°C, followed by spray-drying. Although nearly all industrial processes for the preparation of maltodextrins destined for fat replacement rely on the use of the enzyme α-amylase from various (mainly microbial) sources, more recently other enzymes have also been suggested as alternative biocatalysts for achieving desirable changes in the structure and function of starch. For example, pullulanases and isoamylases both cleave the α-1,6-linkages at the branch points of amylopectin, converting it into a mixture of amylose molecules with α-1,4 linkages only. Both enzymes have become readily available in large quantities at a low cost only relatively recently. Waxy maize starch debranched using isoamylase has been shown to form pastes with a “greasy” feel similar to that of fats (Swinton et al., 1990). A series of patents has also been published recently by researchers from the National Starch & Chemical Company (Chiu, 1990; Chiu and Henley, 1994; Chiu and Zallie, 1989; Zallie and Chiu, 1990) describing the use of debranching enzymes to prepare ingredients suitable for fat replacement as well as other food applications (see Section 6A.6. on specific applications). At the time of writing, however, it was not known whether debranching enzymes were actually being used in commercial processes.

6A.3 CHEMICAL COMPOSITION The gross chemical composition of maltodextrins is related to the botanical source from which they are derived and can, in general, be divided into two broad groups: root starches and cereal starches. The composition of root starches makes them particularly attractive as raw materials for the preparation of maltodextrins for many food applications, including fat replacement. For example, potato and tapioca starches have a low lipid content (0.05 to 0.1 mg/g) compared to cereal starches (0.6 to 0.8 and 0.8 to 0.9 mg/g for corn and wheat starches, respectively). Lipids can be responsible for the presence of offflavors, high turbidity, higher pasting temperatures, and lower viscosity of starch. Similarly, potato and tapioca starches contain less protein (0.06 to 0.1 mg/g) than cereal starches (0.35 and 0.4 mg/g for corn and wheat starches, respectively). Proteins may lead to mealy flavors and a tendency to foam. Finally, potato and tapioca starches contain amylose molecules with longer chains (DP 3,000) than those found in corn and wheat starches (DP 800) and these are thought to retrograde less readily thereby reducing the tendency to cause turbidity and an undesirable texture (BeMiller, 1993; Swinkels, 1985; Whistler et al., 1984). However, whether a starch comes from a tuber or cereal source is not necessarily predictive of all aspects of compositon. For example, some starches, such as potato (tuber) and wheat (cereal) contain more bound phosphate ester groups (0.08 and 0.06% phosphorus, respectively) than other starches from various sources and

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these cause a lower pasting temperature, higher viscosity, and improved clarity (BeMiller, 1993; Swinkels, 1985; Whistler et al., 1984). All of these gross compositional characteristics may influence the processing tolerance and ultimately the texture and flavor of foods containing starch-derived fat replacers. All starches are polymers of a-linked anhydroglucopyranose units. Native starches are composed of amylose, a linear polymer of primarily alpha-1,4 linkages, and amylopectin, also a linear polymer of alpha-1,4 linked units but with about 5% of the bonds in the form of alpha-1,6 branch points. In general, native starches contain amylose and amylopectin in an approximate ratio of 25:75 although speciality starches such as waxy maize starch (99% amylopectin) and amylomaize (50 to 70% amylose) are available (BeMiller, 1993; Zobel, 1992). Unlike highly hydrolyzed products such as high-fructose corn syrup, which have very similar chemical, physical, and organoleptic properties regardless of botanical source, maltodextrins have subtly different properties that are related to their botanical source as well as to the processing method used for their manufacture. Both amylose and amylopectin play imporant roles in determining the functional properties of starch and consequently of the maltodextrins derived from them. The most commonly reported chemical property of maltodextrins is the dextrose equivalent (DE). This is essentially an empirical and somewhat crude measurement of the amount of reducing sugar present, expressed on a dry weight basis, and is a reflection of the extent of starch hydrolysis. In general, as the DE increases, so does the presence of free glucose and oligosaccharides with degrees of polymerization (DP) below 8. Thus, the average molecular weight of the glucose polymers in the maltodextrin decreases as the DE increases (Alexander, 1992). Maltodextrins are frequently complex mixtures of molecular species ranging from glucose to long polymeric (linear and branched) chains so that samples with the same DE prepared by different manufacturers can have different physical and functional properties. Manufacturers of fat replacers derived from starch frequently make claims of superior fat-mimetic performance in their product literature. Yet, the hard experimental evidence (relating superior functionality in real food systems to a unique chemical structure, for example) is often lacking. Consequently, the food product developer could be forgiven for thinking that all commercial maltodextrins currently on the market have more-or-less the same chemical composition and consequently have very similar fat-mimetic properties that are unlikely to be improved by further research and development. However, emerging experimental evidence (discussed in more detail in Section 6A.4) suggests that subtle functional differences between low-DE maltodextrins from different manufacturers do exist. These functional differences could be explained and further exploited in the search for improved fat replacers by subtle differences in fine chemical structure. Thus, the size, shape and degree of branching of the molecules present in maltodextrins may have more importance in determining the fat-mimetic properties of maltodextrins than has been recognized so far. Reports of molecular weight determinations of maltodextrins have been somewhat contradictory, probably due to methodological differences as well as to analytical difficulties caused by the tendency of short chains of amylose to retrograde and precipitate out of solution. Amylose and amylopectin in native starches have been reported to have molecular weights of approximately 160 to 2,600 kDa and 50,000 to 400,000 kDa, respectively (BeMiller, 1993). By comparison, Richter and Schierbaum’s group reported an average molecular weight for low-DE potato maltodextrins prepared using their patented process of around 395 kDa with three principal fractions occurring at 578, 80, and 16 kDa (Braudo et al., 1979). However, only a year later, the same group reported that the molecular weight of low-DE potato maltodextrins was, on average, about 1,000 kDa for about 75% of the product, down to 180 to 360 kDa (molecular weight of glucose

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and maltose) for about 2.5% of the product, with the remaining 22.5% of the product having an unspecified molecular weight (Haenel and Schierbaum, 1980). Using a similar method for preparing low-DE maltodextrins, Anger and colleagues (1981) have reported a broad molecular weight profile (150 to 500 kDa) for a low-DE corn maltodextrin with the larger molecular weight fraction comprising only 25% of the product. By contrast, Bulpin et al. (1984) reported the presence of a high molecular weight fraction (>10 kDa) and a low molecular weight fraction (<10 kDa) in roughly equal proportions in samples of low-DE potato maltodextrins obtained from East Germany. The high molecular weight fraction formed thermoreversible gels and consisted of branched molecules derived from amylopectin. The authors concluded that maltodextrin gels were composed of a network of high molecular weight branched molecules stabilized by interactions with short linear chains and that this fine structure was obtained by the preferential action of α-amylase on the amorphous region of the starch granule, leading to extensive hydrolysis of amylose but only a partial hydrolysis of amylopectin. It is possible that this preferential action of the enzyme was brought about by the specific processing method for preparing maltodextrins developed by Richter and Schierbaum which, unlike most commercial processes, did not involve complete gelatinization of the starch. The reported molecular weights of some commercial maltodextrins available today are shown in Table 6A.1. The significance of molecular weights (or, more precisely, of molecular weight profiles as indicators of fine structure) of maltodextrins has not been fully appreciated to date. For example, Harris and Day (1993) have reported average molecular weights determined by gel permeation chromatography of 180 kDa, 177 kDa, and <20 kDa for commercial fat replacers derived from potato maltodextrin (not named), tapioca maltodextrin (not named), and cornstarch (Stellar™ from A.E. Staley), respectively. Although the average molecular weight reported for Stellar™ was nearly an order of magnitude lower than that found for the potato- and tapioca-derived fat replacers, the authors stated that this difference was not of major importance in determining the fatreplacement properties of Stellar but rather, attributed the functional properties entirely to the microparticulate structure of the creme (these are discussed in more detail in Section 6A.4). More recently, qualitative high precision size exclusion chromatography (HPSEC) of potato maltodextrins prepared without complete gelatinization of the starch prior to enzymic treatment showed a much greater presence of high molecular weight oligomers than in a commercial potato maltodextrin with a similar DE (Roller and Swinton, 1990; Roller et al., 1990). The authors suggested that the difference in the molecular weight profile (i.e., the difference in oligomeric fine structure) of the maltodextrins may have accounted for the difference in performance as fat replacers in low-fat salad dressings (described in more detail in Section 6A.6). The concept of exercising control over the choice of substrate, enzyme, and processing conditions in order to produce a low-DE maltodextrin with a specific structure and superior fat-mimetic properties was further exploited in a recent patent application by Roller and Dea (1995). In this invention, wheat- and potato- derived low-DE maltodextrins were prepared using porcine pancreatic α-amylase at temperatures below those required to achieve gelatinization of the starch. The new maltodextrins were only partly soluble and the molecular weight profiles of their water-soluble fractions were substantially different from those of the fully-soluble potato maltodextrin Paselli SA2 or of the low-DE potato maltodextrin produced by the Richter method (1976a and b). Both the potato and the wheat maltodextrins prepared by Roller and Dea (1995) showed a distinct peak at a molecular weight of around 12 to 20 kDa with oligomers of molecular weight over 20 kDa present in much greater quantities than the oligomers below 12 kDa. By contrast, the potato maltodextrin Paselli SA2 consisted of two main molecular weight

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fractions: the larger fraction was very broadly distributed from around 50 to 180 kDa and the smaller fraction constituted a much sharper peak at around 6 kDa. The low-DE potato maltodextrin prepared using Richter’s method was different again, and showed a very broad distribution with no sharp peaks in the molecular weight range from about 150 to 12 kDa; in addition, there was also a much higher proportion of lower molecular weight material (<5 kDa) than in the other maltodextrins studied (Roller and Dea, 1995). Again, the differences in fine structure were attributed by the authors to improved performance of the new maltodextrins in low-fat salad dressings (discussed in more detail in Section 6A.4 and 6A.6). It is clearly evident from the studies discussed above that the determination of average molecular weights for maltodextrins may be meaningless in the context of fat replacement. Rather, a molecular weight profile (giving size and amount of each molecular species whenever possible) may provide more useful data that could, in the future, be correlated with functional (fat-mimetic) properties.

6A.4 PHYSICAL AND FUNCTIONAL PROPERTIES The chemical properties of starches hydrolyzed to a range of DEs from 0 to 100 are reflected in their physical properties: as the DE increases, so does browning reaction, freezing point depression, hygroscopicity, sweetness, solubility, and osmolality, while viscosity, cohesiveness, film-forming ability, and the ability to prevent large crystal formation all decrease. The broad range of physical properties available have made it possible to use starch hydrolysates in numerous food applications well before the advent of fat replacement. However, within the narrow DE limits of 0 to 20, the differences in the above-mentioned physical properties of maltodextrins are comparatively small. In this respect, maltodextrins are relatively inert materials and as such have been used as nonsweet flavor carriers, bulking agents, and spray-drying aids without risk of undesirable side reactions (Alexander, 1992). The more subtle differences in the fine chemical structure between maltodextrins is reflected in small but important differences in physical properties. The molecular associations involved in gelation and other physical phenomena associated with maltodextrins have been studied extensively on a fundamental level using techniques such as differential scanning calorimetry, mechanical spectroscopy, small-angle and wide-angle X-ray diffraction, transmission electron microscopy, electron spin resonance, and NMR spectroscopy (Kasapis et al., 1993a; Levine and Slade, 1986; Reuther et al., 1983 and 1984; Schierbaum et al., 1990). For example, Kasapis and colleagues compared the gelation behavior of the low-DE potato maltodextrins Paselli SA2 (DE 2) and Paselli SA6 (DE 6) over a range of temperatures and concentrations, using both visual and mechanical spectroscopic techniques to determine the time required for the formation of self-supporting networks (gels). The results showed that at equivalent temperatures and concentrations, SA2 gelled between 20 and 60 times faster than SA6. Furthermore, whereas the concentration-dependent gelling properties of SA2 could be predicted from the cascade theory for normal polymer networks, the gelling pattern of SA6 suggested a different mechanism, such as the agglomeration of short, aggregated helices (Kasapis et al., 1993a). However, extensive efforts to relate these data (usually obtained in model systems) directly to sensory (textural and flavor) performance of the maltodextrins as fat replacers in complex food systems have generally not been made (with a few notable exceptions, discussed in more detail below). A wide range of commercial maltodextrins, some of which have been developed with specific low-fat food applications in mind (e.g., for baked products), are available (see Appendix). However, much of the literature on the functional properties of starch-derived

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fat replacers (whether in model systems or in foods) is produced by the manufacturers themselves and the data are very rarely in a form that allows direct comparison between different brands. The difficulty of making a rational choice of a fat-replacing maltodextrin on the basis of reported physical properties is illustrated in the following paragraphs. Native starch granules vary in size from 0.5 to 175 µm in diameter and occur in shapes ranging from spheres, ellipsoids, polygons, platelets, and irregular tubules (Zobel, 1992). The granules are partially crystalline which accounts for their insolubility in water. It has been suggested that spheroidal native starches with granule diameters similar to those of lipid micelles (0.1 to 3 µm) might have potential for use as fat replacers without further processing (Glicksman, 1991; Lucca and Tepper, 1994; Setzer and Racette, 1992). Although native starches from some cereals and grass seeds have granule shapes and diameters that fit this criterion, the lack of availability of the raw materials in volumes sufficient to satisfy the fat-replacer market makes their use economically unattractive. Nevertheless, the concept of mimicking the particle size of fat has been used recently in the development of a commercial process by A.E. Staley based on a combination of acid hydrolysis and shear. In this process, insoluble cornstarch in water is treated to give a firm, deformable creme known as Stellar™ (Harris and Day, 1993). The fat-like properties of Stellar™ have been ascribed to the particle gel structure of the creme, shown by transmission electron microscopy to consist of loosely aggregated submicron size particles. The particle gel character was maintained with multiple heating/cooling cycles within the temperature range 0 to 60°C although heating the creme to temperatures greater than 108°C solubilized the starch and reduced the functional properties of the fat replacer. However, as discussed in Chapters 1 and 4, it is debatable whether particle size alone can justifiably be used as the sole criterion of suitability for fat replacement. Most of the commercial maltodextrins available for fat replacement have lost the granular structure of the native material and are fully soluble in water. However, the lowDE potato maltodextrins prepared by Richter’s group have been reported to be only partly soluble (Schierbaum et al., 1977) due to the presence of particles varying in size from 30 to 110 µm, an aspect which would have rendered them gritty to the palate. It has been suggested by Schierbaum that the low-DE potato maltodextrins could be made to dissolve in cold water by high-shear homogenization or by heating to 75 to 80°C (Schierbaum et al., 1977). By contrast, the potato and wheat maltodextrins reported by Roller and Dea (1995) have been characterized by the presence of partially gelatinized starch granules exhibiting birefringence under crossed-polarized light, as well as having other characteristic parameters such as a unique molecular weight profile (see Section 6A.3). It has been proposed by many researchers in the field that the key physical characteristic associated with maltodextrins useful in fat replacement is their ability to form soft, spreadable, thermoreversible gels with melt-in-the-mouth properties that give a fatlike mouthfeel to food products (Richter et al., 1976a and b). This property was originally thought to be unique to maltodextrins from root starches. Richter and his colleagues have stipulated that potato starch was the preferred source of maltodextrins for thermoreversible gels while cereal starches constituted less suitable raw materials. Yet, in 1981 a patent from the East German Academy of Sciences, published by a group of researchers different from that of Richter and Schierbaum, reported a process for the preparation of a starch-derived fat replacer from maize starch (Anger et al., 1981). The temperature regime included two stages: first, the native starch slurry was heated slowly to 50 to 60°C and held at this temperature (well below the gelatinization temperature for maize) for 3 to 30 min; second, the temperature was increased in steps of 1 to 5°C to 62 to 70°C and held from 10 to 120 min. All the other processing steps were similar to Richter’s patents on potato starch (1976a and b). The products obtained had a DE of 4 to 8 and reportedly formed thermoreversible gels (Anger et al., 1981; Schierbaum, 1991).

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In a patent assigned to National Starch & Chemical Co., maltodextrins with DE<5 derived from tapioca starch were also reported to form thermoreversible gels with gel strengths of 65 to 930 g at 25 to 35% solids measured using a Stevens Texture Analyser (Lenchin et al., 1985). Yet, in the same patent, there is a statement in the summary of the invention claiming that the modified starches covered by the patent (from tapioca, corn, and potato) do not form gels but can nevertheless be used as fat replacers in products such as ice cream and spreads. Furthermore, the tapioca-derived, enzymically prepared, Instant N-Oil from National Starch & Chemical has been on the market as a fat replacer for a number of years, as has the corn-derived Maltrin® MO40 sold by GPC. Finally, the work of Roller and Dea (1995) suggests that gel strengths of more than 25 g/mm at a concentration of 20% and measured using a Stevens Texture Analyzer (hemispheric probe diameter 13 mm) may be undesirable for fat replacement purposes. Therefore, it is not entirely clear from the literature whether the ability to form thermoreversible gels is an absolute requirement for successful fat replacement using maltodextrins. In the last 10 years, a veritable armory of experimental techniques for rheological analysis has become available and these have been used to characterize the physical properties of foods and food ingredients, including fats and fat replacers (Chapter 9; Clark, 1987; Prentice, 1992). As an example, the heterogeneous, submicron, particle network of A.E. Staley’s Stellar™ (acid- and shear-modified cornstarch) has been sho wn to have thixotropic rheological properties similar to those of hydrogenated vegetable shortening when tested in a model system using a Bohlin Model VOR rheometer (Harris and Day, 1993). The G′ values for shortening and the Stellar™ creme (25% solids) dropped off dramatically with increasing strain at relatively lo w strain values, displaying short textures, whereas polymer gels prepared from either a 20% “traditional starch thickener” (brand not specified) and a 1.25% xanthan gum solution showed no drop in G′ values at low strain values consistent with a long texture (Harris and Day, 1993). The work of Kasapis et al. (1993a) on low-DE potato maltodextrins described above provides another example of recent advances made using rheological techniques. Rheological comparisons in real food systems, e.g., low-fat spreads, in which a multitude of ingredients can be expected to play a role, have also been carried out and some of these are described in more detail in Section 6A.6. As might be expected, maltodextrins share some of the undesirable physical properties associated with native starches. For example, the tendency of amylopectin to retrograde very slowly is manifested in low-fat food products containing starch-derived fat replacers by giving rise to such phenomena as set-back in low-fat spoonable salad dressings stored for long periods of time (Biliaderis, 1992; Biliaderis and Zawistowski, 1990). Similarly, low-DE maltodextrins can suffer from variable freeze-thaw stability and unreliable heatand acid-stability. Finally, many low-DE maltodextrins, unless specifically treated, can impart an undesirable, starchy, off-flavor to delicate foods if used at high concentrations.

6A.5 INTERACTIONS WITH OTHER FOOD INGREDIENTS Currently, there is no single fat replacer that contributes all of the functional and sensory qualities of fat to all reduced-fat food products. In other words, there is no “magic bullet” in fat replacement nor is it likely that one will be found in the future. This applies to low-DE maltodextrins as much as to any other fat replacer. The problem is further compounded by the fact that most studies of fat replacer functionality are carried out on a single ingredient at a time in an effort to develop systems for predictive formulation. Unfortunately, as pointed out by Lillford and Norton (1994), such tests on separate ingredients cannot usually be combined linearly to predict product performance. Nevertheless, recent attempts have been made to elucidate some of the possible ingredient

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interactions that can be expected in model systems and in complex foods in an effort to optimize ingredient performance. Protein/maltodextrin interactions are but one such example of important interactions occurring in foods in which fat has been replaced by low-DE maltodextrins. Kasapis and colleagues have studied the effect of thermodynamic incompatibility in mixed solutions of gelatin and low-DE potato maltodextrins, two ingredients commonly used in the manufacture of low-fat spreads, in order to attain an in-depth understanding of the role that these ingredients play in the process of phase inversion and solvent partition between polymeric phases (Kasapis et al., 1993a, b, c, and d). Using visual observation and optical techniques and a temperature (45°C) at which the individual polymers were stable as disordered coils over long periods of time, it was shown that conformational ordering (and consequent precipitation) of maltodextrins derived from potato starch can be accelerated by the presence of gelatin in the same solution phase. The amount of maltodextrin precipitated was proportional to the square of its initial concentration and to the first power of gelatin concentration, indicating that gelatin was driving the self-association and aggregation of maltodextrins when both polymers were present in a single liquid phase. Furthermore, proton NMR showed that the precipitated maltodextrin was higher in molecular weight and in the degree of branching than the material remaining in solution (Kasapis et al., 1993b). In a subsequent paper, the behavior of the same polymers at lower temperatures (5°C) was examined using differential scanning calorimetry, mechanical spectroscopy, and light microscopy (Kasapis et al., 1993c). The results indicated that there was no direct coupling between gelatin and maltodextrin in mixed gels and that phase inversion from a gelatin-continuous network with maltodextrin inclusions to a maltodextrin-continuous network with gelatin as the dispersed phase occurred over a very narrow range of composition. Finally, Kasapis and colleagues also compared the experimental storage moduli (G′ ) for mixed gel systems with those of the constituent polymers in isolation using the Takayanagi et al. (1963) blending laws and obtained quantitative data on the distribution of solvent between the two phases for more than 30 gelatin/maltodextrin combinations (Kasapis et al., 1993d). The fundamental background information obtained in these studies allowed Gupta and Kasapis (1995) to pinpoint the brittle and elastic character of maltodextrins and proteins, respectively, and to develop a low-fat spread formulation in which a relatively soft, milk protein-continuous matrix provided the solid-like structure whereas the stronger maltodextrin filler introduced micro-heterogeneities to encourage plastic failure (described in more detail in Section 6A.6). Many of the more recently introduced commercial fat replacers are based on the combined properties of two or more macromolecule components, one of which is frequently a low-DE maltodextrin. For example, Rice Trin 3 Complete (Zumbro, Inc.) contains an enzymically hydrolyzed rice maltodextrin and 10% rice protein present in 1 to 5 µm particles, thereby combining the benefits of a gelling starch with those of a microparticulated protein (Setzer and Racette, 1992). Another example is Slimgel®, a blend of gelatin and galactomannan, described in more detail in Chapter 12; indeed, Slimgel® is an example of a proprietary blend in which the concept of thermodynamic incompatibility has been exploited in a way that is similar to the work of Kasapis on maltodextrin/caseinate systems in low-fat spreads (see Section 6A.6). However, as our understanding of the action and interaction of hydrocolloids in foods improves with time, recourse to proprietary blends designed specifically for fat replacement may not be necessary. As with native starches, low-DE maltodextrins can interact with a variety of other food ingredients such as flavors, emulsifiers, sweeteners, etc. (Godshall and Solms, 1992). Interactions between maltodextrins and lipid-based materials are discussed in more detail in Chapter 6B.

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6A.6 APPLICATIONS 6A.6.1 LOW-FAT SPREADS In the first wave of reduced-fat product development in the West, the so-called “halvarines” were developed in which the fat content of butter and margarine was reduced by half from the traditional 80% to about 40%, to allow for the now widely available and popular low-fat spreads. In most of these low-fat spreads, gelatin was, and still is, used in the aqueous phase. As consumer pressure for “light” products grew, manufacturers continued to strive to reduce the fat content of spreads even further, giving the so-called quarterines (20% fat) and even fat-free (actually 3% fat) versions of the product. However, at levels of 3 to 5% fat, the spreads were water-continuous and proteins like gelatin tended to produce an undesirable, gel-like structure. Alternative proteins (e.g., caseinates) were introduced and major reformulations of ingredients and concepts were necessary to achieve satisfactory products. Indeed, it can be said that to date, very few no-fat spreads of acceptable quality have reached and stayed on the market. In this respect, the very recent work of Kasapis and his colleagues at Cranfield University in the U.K. has been instrumental in demonstrating how dramatic quality improvements could be made by exploiting the interaction of maltodextrins with proteins (see Section 6A.5) within spreadable products and this work is discussed in more detail below. One of the first requirements for a successful low-fat spread or soft cheese product is that it should have the spreadable properties of the full-fat product. Kasapis used compression analysis, a known rheological technique (Prentice, 1992), to characterize and compare existing full-fat and low-fat spreads on the market by creating a series of comparative force-deformation profiles for each product. In this type of analysis, a constant stress is applied to a sample and the generated strain is recorded until a certain predetermined deformation is reached (usually between 70 and 90% of the original height). As illustrated in Figure 6A.1b, spreadable butter (Anchor) was shown to display a characteristic stress-strain profile: a smooth shoulder was followed by a shallow dip which was in turn followed by a gradual but steady rise in the curve. The curve obtained was quantified by the force at the point of failure (maximum stress, σm) and at the maximum depth of the dip (plastic stress, σp). A σp to σm ratio between 0.95 and 1.00 was typical of the spreadable butter Anchor (Chronakis and Kasapis, 1995 and 1996; Gupta and Kasapis, 1995; Kasapis et al., 1996). Similar ratios (0.95 to 1.00) were obtained for the full-fat soft cheese Philadelphia (a water continuous emulsion), ordinary butter, and Flora margarine (Gupta and Kasapis, 1995) although the absolute stress values differed, as illustrated in Figure 6A.1b for Anchor spreadable butter (left hand y-axis scale from 0 to 30 kPa) and Flora margarine (right hand y-axis scale from 0 to 10kPa). By contrast, four commercial low-fat spreads failed to demonstrate the same stress-strain profiles. St. Ivel’s Gold (a halvarine spread) and Gold Lowest (25% fat, containing at least 6% protein and 4% starch in the aqueous phase) showed a sharp breaking pattern and had sp to sm ratios of about 0.82, revealing a gel-like character (Figure 6A.1a). In water-continuous spreads such as Unilever’s Promise containing a gelatin-maltodextrin aqueous phase and believed to have been produced according to the patented method of Cain et al. (1989), fracture occurred (Figure 6A.1a). In the curves obtained for Gold, Gold Lowest, and Promise, no near-horizontal region of plastic flow was observed; instead, there was an inflection point where the stress went through a minimum value, followed by a sharp increase in the curve. In Safeway’s Very Low Fat Spread, the elastic mechanics of a gelatin network were avoided by replacing gelatin with the microparticulated protein Simplesse® (for more detail on this fat replacer, see Chapter 8). However, the outcome was a sticky product reminiscent of a thick Greek yogurt with no apparent

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Figure 6A.1 Force-deformation profiles for: (a) St. Ivel’s Gold Low Fat Spread (40% fat), St. Ivel’s Gold Lowest Fat Spread (25% fat, 6% protein, 4% starch), Unilever’s Promise (3% fat and containing gelatin and starch, believed to be manufactured according to the method of Cain et al., 1989) and Safeway’s Very Low Fat Spread (3% fat and containing the microparticulated protein Simplesse®). (b) Anchor spreadable butter (80% fat), Flora margarine (80% fat) and the water-continuous experimental spreads prepared according to the method of Gupta and Kasapis (1995) and containing 4.8% fat, 2.3% caseinate, 11.5% Cerestar’s maltodextrin C*Pur 01906 and 5% inulin (Product A) and 4.5% fat, 4.7% caseinate and 15.9% Cerestar’s potato maltodextrin C*Pur 01906 (Product B). Cylindrical disks of 26 mm length and diameter were compressed at 0.8 mm/s at 5°C. Note that the arrow below each product name indicates the location (left or right) of the appropriate y-axis. (Compiled from Chronakis, I. S. and Kasapis, S. 1995 and 1996; Gupta, B. B. and Kasapis, S., 1995; Kasapis, S. et al., 1996, with permission from S. Kasapis.)

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yield points on the curve during a compression cycle (Figure 6A.1a, note the difference in scales of the y-axis). Tesco’s Very Low Fat Spread (5% fat) and Sainsbury’s Sunflower Lowest (5% fat) gave similar results (Gupta and Kasapis, 1995). Having demonstrated instrumentally and quantitatively what consumers already knew — that none of the existing, very-low-fat spreads on the market resembled their full-fat counterparts — Kasapis and his colleagues went on to develop mixed biopolymer systems (including maltodextrins) for very low-fat spreads based on the concept of phase inversion due to thermodynamic incompatibility (see Section 6A.5 and Chapters 7C, 9, and 12). New, phase-separated, low-fat spread formulations were developed in which a relatively soft, milk protein-continuous matrix provided the solid-like structure whereas the stronger maltodextrin filler introduced micro-heterogeneities to encourage plastic failure. Phase separation could be further manipulated by adjusting the concentration of the hydrocolloids and of salt. Figure 6A.1b shows the stress-strain curves for such spreads made with 4.8% fat, 2.3% caseinate, 11.5% maltodextrin (Cerestar’s C*Pur 01906) and 5% inulin (product A) and 4.5% fat, 4.7% caseinate, and 15.9% maltodextrin (C*Pur 01906, product B). In both cases, the rheology of Flora margarine was successfully matched with low-fat, water-continuous products. Furthermore, the shapes of the experimental stress/strain curves and the σp/σm ratios matched those of Anchor spreadable butter, although, of course, the absolute stress values differed. The absolute stress required to deform the low-fat products was smaller than that required for butter indicating good spreading characteristics at refrigerator temperatures. Therefore, the authors postulated that the maintenance of the σp/σm ratio (measured at 5°C) between the values of 0.95 and 1.00 was the most important rheological characteristic when attempting to match lowfat spreadable products with full-fat ones (Chronakis and Kasapis, 1995; Gupta and Kasapis, 1995). As has been pointed out in Chapters 1 and 4, fat plays a multitude of roles in foods and texture determination is but one of them. Low-fat products which have been successfully matched with full-fat versions in terms of texture may fail to meet quality expectations in terms of flavor release. Therefore, in the above work by Kasapis and colleagues, sensory profiling of the newly developed low-fat spreads was undertaken to check melting temperatures determined instrumentally and to assess overall sensory acceptability. Of the maltodextrins studied (C*Pur 01906, Paselli SA2, N-Lite™ D, NOil, Maltrin M040, Lycadex 100, Optagrade and TrimChoice), Cerestar’s C*Pur 01906 and Opta Food Ingredients’ Optagrade were considered preferable because at least 50% of the gel structure present at 5°C was lost at oral temperatures (around 37°C) and this characteristic was associated with better flavor release. Other maltodextrins tended to retain their gel structure in the mouth and were considered less suitable (Gupta and Kasapis, 1995). Dynamic mechanical measurements on the concentration dependence of the storage modulus (G′ ) and the melting profiles of the above maltodextrin gels in combination with sensory analysis of water-continuous spreads showed the potato maltodextrin Cerestar C*01906 to be the most efficient structuring agent with the best organoleptic performance. This appeared to be linked to a low minimum gelling concentration (about 12%) compared to that of the other maltodextrins which gelled at concentrations of over 18%. Therefore, it was possible to produce spreads using lower concentrations of C*Pur 01906 than the other maltodextrins thereby avoiding the unpleasant starchy oral perception associated with high levels of maltodextrins in foods. The spreads also contained minor amounts of nongelling hydrocolloids, such as xanthan gum, locust bean gum, modified starch, or soluble vegetable fiber such as inulin. It was recommended that no nonaggregate forming gelling agents such as gelatin should be present in the spreads to avoid a gel-like structure (Gupta and Kasapis, 1995).

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6A.6.2 OTHER FOOD APPLICATIONS One of the most common applications for maltodextrins as fat mimetics is in pourable and spoonable low-fat salad dressings. In reformulating these types of products, special attention needs to be paid to developing new flavor systems, combating increased translucency and avoiding excessive setback during storage due to starch retrogradation. Another common application for maltodextrins as fat replacers is in soups, sauces, and gravies. In addition to mimicking the “creamy” mouthfeel of fat in these products, the maltodextrin of choice needs to be resistant to heat and to freeze-thaw cycling (if destined for a frozen food product). In dry mix applications, ability to hydrate quickly and retain its properties with minimal stirring and after heating is important (Yackel and Cox, 1992). Specific formulations for a low-fat salad dressing and a butter sauce are given in Chapter 6B. Low-fat frozen desserts such as sorbets and ice milk have been available for years but they have always lacked the creamy character of full-fat ice cream. Reduced-fat versions of ice cream have often suffered from a lack of richness, body, character, flavor, and mouthfeel. Although development of ice crystals upon heat shock and increased hardness in the presence of fat mimetics can be a problem (Yackel and Cox, 1992), incorporation of maltodextrins into frozen desserts to impart a creamy mouthfeel has met with some success. Maltodextrins have also been recommended for use as fat replacers in meat products such as frankfurters and hamburgers, certain baked products, cheese spreads, microwaveable cheese sauces, sour cream, dairy-style creamed fillings, toppings, and puddings (Anon., 1990; Egbert et al., 1991; Yackel and Cox, 1992). Specific formulations for a low-fat frozen dessert and a cheesecake are given in Chapter 6B. Food applications recommended in the early patents by Richter et al. (1976a and b) were low-fat mayonnaise (17% fat), chocolate mass (4% fat), spreads (32% fat), a spice mix, and an instant dessert powder. Corn-derived maltodextrins with DEs from 4 to 8 were recommended for low-fat mayonnaise, sausages, confectionery creams, and ice cream (Anger et al., 1981). Potato maltodextrins prepared by the Richter method were used in the late 1980s in commercial reduced-fat ice cream and in low-fat salad dressings containing 26% fat and 16% low-DE maltodextrin. The dressings had a cuttable rather than a spoonable consistency and suffered from a starchy aftertaste. Although popular in East Germany (Schierbaum, 1991), it is unlikely that the dressings would have been well-received by the pan-European or American consumer. In a recent study using a low-DE potato maltodextrin prepared without full gelatinization of the starch and a commercial potato maltodextrin with the same approximate DE, informal sensory assessment demonstrated that the experimental maltodextrin afforded thicker and less sharp spoonable dressings (15% oil) than the commercial product used at the same concentration; the improved performance was ascribed by the authors to the more optimal fine structure of the new maltodextrin (Roller et al., 1990). In the same study, fat reductions from 32 to 12.2% in British breakfast sausages containing 2.5% potato maltodextrin were also reported; in sensory tests, the low-fat sausages were preferred in terms of flavor and texture to commercially available low-fat sausages while cooking performance showed reduced weight losses. More recently, it has been shown that dressings containing no added oil but prepared with a wheat maltodextrin matched the rheological and sensory profile of dressings containing 32% oil more closely than similarly prepared dressings containing a potato maltodextrin obtained from Schierbaum’s group in Germany or the commercial tapioca-derived Instant N-Oil obtained from National Starch & Chemical Co. (Roller and Dea, 1995). Again, the authors have suggested that the difference in the molecular weight profile (oligomeric fine structure) of the maltodextrins together with the presence of partially gelatinized starch granules accounted for the difference in performance as fat replacers.

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More recently, a study comparing the sensory and physical performance of Avebe’s potato maltodextrin Paselli SA2 and National Starch & Chemical Co. tapioca maltodextrin N-Oil in a reduced-calorie frozen dessert was reported (Specter and Setzer, 1994). The effect of an artificial sweetener/bulking agent combination (Nutrasweet’s polydextrose-aspartame) was also examined in this study. The basic formulation consisted of cream (37% fat), nonfat dry milk, sucrose, and water to give final concentrations of 12% milk fat, 10% nonfat milk, and 16% sucrose (total solids content was 38%). A total of 21 formula variations were prepared including those in which the fat content was 100, 66, 33 and 0% of the 12% milk fat in the control recipe. The removed fat was replaced by one part Paselli SA2 or N-Oil and three parts water. On sensory assessment following 0 and 140 d of storage, none of the high-fat or low-fat products were judged to be different in terms of gumminess or coldness. No significant differences in terms of any other sensory parameters were observed between the full-fat frozen dessert and the desserts prepared with Paselli SA2 and a fat level of 66 and 33% of the control. Desserts prepared with Paselli SA2 at a level of 0% fat and all the low-fat desserts prepared with N-Oil (66, 33 and 0% of the control milk fat) differed from the control in at least one or more sensory parameters other than gumminess or coldness. Desserts prepared with N-Oil were perceived as more chalky than those prepared with Paselli SA2. The results also suggested that the polydextrose/aspartame mix may have compensated not only for the functional properties of sucrose but also for those of the milk fat (for a detailed description of polydextrose, see Chapter 11). Physical measurements such as viscosity, melting rate, and resistance to deformation did not correlate highly with sensory properties. In another study, 182 consumers were asked to compare the organoleptic properties of strawberry-flavored yogurt containing either no supplements or supplemented with milk fat or one of five fat replacers (Pfizer’s Litesse® [see Chapter 11], National Starch & Chemical Co. tapioca maltodextrin N-Oil, Avebe’s potato maltodextrin Paselli SA2, and Roquette Frères’s maltodextrins Lycadex® 100 and 200) using a 9-point hedonic scale (Barrantes et al., 1993). The yogurts were prepared using reconstituted skim milk powder (14% total solids) and 1% sugar. The experimental yogurt batches were fortified with 1.5% anhydrous milk fat or one of the above-mentioned fat replacers. The starter culture was added at 16g/100 l and the processed strawberry fruit was added at a level of 15%. Overall sensory scores showed that all the yogurts were liked by the majority of consumers. The authors concluded that all the fat replacers tested were suitable for the manufacture of acceptable reduced-fat yogurt. However, given that the control yogurts containing no added fat and those containing added fat (1.5%) were judged equally acceptable and the difference between the fat content of the yogurts was so small, it is debatable whether any conclusions can be drawn from this study about the comparative merits of the five fat replacers. When incorporated in low-fat ice cream at a level of 1%, debranched waxy maize starch has been shown to impart a creamy texture and improved flavor (Swinton et al., 1990). In addition, debranched waxy maize starch showed some promise as a potential fat replacer in both pork pie filling and crust (Swinton et al., 1990). Other workers in the field have also noted that enzymically debranched maize starches had a fat-like texture useful in fat replacement (Chiu, 1990), as well as having other physical properties of interest, such as low hot viscosity, high gel strengths, and emulsification ability. The latter properties would render the debranched starches suitable for food applications such as jelly gum confectionery, caseinate replacement in imitation cheese, stable cloud formation in beverages, and general thickening and bonding (Chiu and Zallie, 1989; Zallie and Chiu, 1990). More recently, it has also been suggested that debranched starches could be used as opacifiers in low-fat foods (Chiu and Henley, 1994). It is not known whether some of the commercial maltodextrins available on the market today have been produced using debranching enzymes.

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6A.7 NUTRITIONAL, TOXICOLOGICAL, AND LEGISLATIVE ASPECTS Maltodextrins are metabolized similarly to native starch; consequently, they have no toxicological implications and may be used by diabetics. On a weight for weight basis, maltodextrins provide 4 kcal/g. However, in fat replacement applications, maltodextrins are typically used as gels or pastes with a water:maltodextrin ratio of around 3:1, thereby reducing the calorie content further to around 1 kcal/g. Using rats as experimental subjects, Harris (1994) concluded that the inclusion of low-fat foods containing a commercial potato maltodextrin (Avebe’s Paselli SA2) as fat replacer was an effective way of reducing overall fat intake although total energy intake was not affected. For a more detailed discussion of this study, see Chapter 2. The U.S. FDA has recognized the use of maltodextrins in foods under the Code of Federal Regulations Title 21 (21 CFR 184.4444). Most commercial fat replacers derived from starch carry label designations of either “modified starch” or “maltodextrin” (Table 6A.1). For example, A.E. Staley Manufacturing Co.’s Stellar™ (from corn), StaSlim™ 142 and 143 (from potato), Sta-Slim™ 150 and 151 (from tapioca), and StaSlim™ 171 (from waxy maize) are labeled as “food starch — modified.” On the other hand, Avebe’s Paselli SA2 (from potato) can be labeled as “maltodextrin,” as discussed in Chapter 6B.

6A.8 FUTURE PROSPECTS In recent years, there has been a general trend in the food industry to replace chemical methods of processing with those relying increasingly on enzymic treatment. This trend has been fueled by increasing consumer demand for more “natural” methods of processing that have a less damaging impact on the environment and has been underpinned by the increased availability of highly specific enzymes at a very low cost. For the ingredient manufacturer, perhaps the most attractive aspect of enzymic preparation of maltodextrins is the potential to tailor the structure of starch for specific applications. Although acid conversion of starch leads to remarkably reproducible saccharide compositions for any given degree of hydrolysis, it is precisely this reproducibility and the random action of acid that limits the usefulness of the method. With the range of specific enzymes, substrates, and processing control measures now available, it should be possible to select an optimized processing mix to obtain a specific molecular structure with targeted physical properties for use in specific fat replacement applications. Starches from genetically engineered plants with properties different from their native counterparts may also provide promising new industrial materials, including fat mimetics. Thus, although starch-derived fat replacers may not be suitable for every food application, their relatively low cost, wide availability, conventional storage and handling procedures, together with the potential for further refinement of structure and function, will ensure their continued use in the food industry. Finally, given a thorough knowledge and understanding of the action and interaction of food ingredients, it is possible that the food technologist of the future will use a systems approach based on a combination of two or more fat replacers and/or other food ingredients, coupled with formulation and processing changes, to develop high quality low-fat products that consumers will accept. This approach, although by no means an easy option, is also advocated in Chapter 1 and is gradually being accepted by the food industry. However, since our knowledge and understanding of ingredient interactions in foods is as yet incomplete, the full benefits of this approach may only be realized once additional scientific data become available.

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REFERENCES Alexander, R.J., Maltodextrins: Production, properties and applications, in Starch Hydrolysis Products, Schenk, F.W. and Hebeda, R.E., Eds, VCH Publishers, New York, 1992, 233. Amylase Research Society of Japan, Ed., Handbook of Amylases and Related Enzymes, Committee of the Amylase Research Society of Japan, Eds., Pergamon Press, Oxford, 1988. Anger, H., Lexow, D. and Berth, G., Verfahren zur enzymatischen Herstellung von Hydrolyseprodukten aus Maisstärke, German Democratic Republic Patent 0,152,582, 1981. Anonymous, Fat substitute update, Food Technol., 44(3), 92, 1990. Barrantes, E., Tamime, A.Y., and Sword, A.M., Fat-free yogurt — like or dislike?, Dairy Ind. Int., 58(11), 33, 1993. BeMiller, J.N., Starch-based gums, in, Industrial Gums, Whistler, R.L. and BeMiller, J.N., Eds., Academic Press, San Diego, 1993, 579. Biliaderis, C.G., Structures and phase transitions of starch in food systems, Food Technol., 46 (6), 98, 1992. Biliaderis, C.G. and Zawistowski, J., Viscoelastic behavior of ageing starch gels: Effects of concentration, temperature and starch hydrolyzates on network properties, Cereal Chem., 67, 240, 1990. Braudo, E.E., Belavtseva, E.M., Titova, E.F., Plashchina, I.G., Krylov, V.L., Tolstoguzov, V.B., Scherbaum, F.R., Richter, M., and Berth, G., Struktur und Eigenschaften von Maltodextrin Hydrogelen, Stärke, 31(6), 188, 1979. Bulpin, D.V., Cutler, A.N., and Dea, I.C.M., Thermally-reversible gels from low D.E. maltodextrins, in Gums and Stabilisers for the Food Industry, Vol. 2, Phillips, G.O., Wedlock, D.J., and Williams, P.A., Eds., Pergamon Press, Oxford, 1984, 475. Cain, F.W., Clark, A.H., Dunphy, P.J., Jones, M.G., Norton, I.T., and Ross-Murphy, S.B., Edible plastic dispersion, European Patent 0,298,561, 1989. Chiu, C.-W., Partially debranched starches and enzymatic process for preparing the starches, European Patent Application 0,372,184 A1, 1990. Chiu, C.-W. and Henley, M.J., Debranched starch opacifier, European Patent Application EP 0,616, 778 A1, 1994. Chiu, C.-W. and Zallie, J.P., Method for manufacture of jelly gum confections, U.S. Patent 4,886,678, 1989. Chronakis, I.S. and Kasapis, S., Preparation and analysis of water continuous very low fat spreads, Lebensmitt. Wiss. Technol., 28, 488, 1995. Chronakis, I.S. and Kasapis, S., A rheological study on the application of carbohydrate-protein incompatibility to the development of low fat commercial spreads, Carbohyd. Polym., in press, 1996. Clark, A.H. and Ross-Murphy, S.B. Adv. Polym. Sci., 83, 57, 1987. Duxbury, D.D., Fat substitute with fiber now commercialized, Food Process., March, 82, 1993. Egbert, W.R., Hoffman, D.L., Chen, C., and Dylewski, D.P., Development of low-fat ground beef, Food Technol., 45(6), 64, 1991. Food and Drug Administration, 21 Code of Federal Regulations, Title 21, Office of the Federal Register, National Archives and Records Administration, Washington, D.C., paragraph 184.1444, 1983. Glicksman, M., Hydrocolloids and the seach for the “oily grail,” Food Technol., 45 (10), 94, 1991. Godshall, M.A. and Solms, J., Flavor and sweetener interactions with starch, Food Technol., 46(6), 140, 1992. Gupta, B.B. and Kasapis, S., Water-continuous spread, European Patent Application 0, 672, 350 A2, 1995. Haenel and Schierbaum, F., Die Verwendung von gelbildenden Maltodextrinen (SHP) zur Herstellung energiereduzierter Lebensmittel, Ernärhung, 4(7), 306, 1980. Harkema, J., Personal communication, 1994. Harris, D.W. and Day, G.A., Structure vs. functional relationships of a new starch-based fat replacer, Starch, 45(7), 221, 1993. Harris, R.B.S., Factors influencing energy intake of rats fed either a high-fat or a fat mimetic diet, Int. J. Obesity, 18, 632, 1994. Hoover, W.J., Memorandum to Members of the Technical Committee, Corn Industries Research Foundation, Inc., 1957. As referred to in Alexander, 1992. Inglett, G.E., USDA’s oatrim replaces fat in many food products, Food Technol., 44(10), 100, 1990.

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Inglett, G.E., Method of making a soluble dietary fiber composition from oats, U.S. Patent 4,996,063, 1991. Inglett, G.E. and Grisamore, S.B., Maltodextrin fat substitute lowers cholesterol, Food Technol., 45(6), 104, 1991. Kasapis, S., Alevisopoulos, S., Abeysekera, R., Manoj, P., Chronakis, I., and Papageorgiou, M., Scientific and technological aspects of polymer incompatibility in mixed biopolymer systems, in Gums and Stabilisers for the Food Industry, Vol. 8, Phillips, G.O., Williams, P.A., and Wedlock, D.J., Eds., IRL Press, Oxford, 1996, in press. Kasapis, S., Morris, E.R., Norton, I.T., and Clark, A.H., Phase equilibria and gelation in gelatin/maltodextrin systems — Part I: gelation of individual components, Carbohydr. Polym., 21, 243, 1993. Kasapis, S., Morris, E.R., Norton, I.T., and Gidley, M.J., Phase equilibria and gelation in gelatin/maltodextrin systems — Part II: polymer incompatibility in solution, Carbohydr. Polym., 21, 249, 1993. Kasapis, S., Morris, E.R., Norton, I.T., and Brown, R.T., Phase equilibria and gelation in gelatin/maltodextrin systems — Part III: phase separation in mixed gels, Carbohydr. Polym., 21, 261, 1993. Kasapis, S., Morris, E.R., Norton, I.T., and Clark, A.H., Phase equilibria and gelation in gelatin/maltodextrin systems — Part IV: composition-dependence of mixed-gel moduli, Carbohydr. Polym., 21, 269, 1993. Lenchin, J.M., Trubiano, P.C., and Hoffman, S., Converted starches for use as a fat- or oil-replacement in foodstuffs, U.S. Patent 4,510,166, 1985. Levine, H. and Slade, L., A polymer physico-chemical approach to the study of commercial starch hydrolysis products (SHPs), Carbohydr. Polym., 6, 213, 1986. Lillford, P.J. and Norton, I.T., High molecular weight food additives: Where are we going?, Trends Food Sci. Technol., 5, 196, 1994. Lucca, P.A. and Tepper, B.J., Fat replacers and the functionality of fat in foods, Trends Food Sci. Technol., 5, 12, 1994. Morehouse, A.L. and Lewis, C.J., Low-fat spread, U.S. Patent 4,536,408, 1985. Morehouse, A.L. and Sander, P.A., Low DE starch hydrolyzates, U.S. Patent 4,689,088, 1987. Prentice, J.H., Dairy Rheology: A Concise Guide, VCH Publishers, New York, 1992. Reuther, F., Damaschun, G., Gernat, Ch., Schierbaum, F., Kettlitz, B., Radosta, S., and Nothnagel, A., Molecular gelation mechanism of maltodextrins investigated by wide-angle X-ray scattering, Colloid Polym. Sci., 262, 643, 1984. Reuther, F., Plietz, P., Damaschun, G., Purschel, H.-V., Krober, R., and Schierbaum, F., Structure of maltodextrin gels — a small angle X-ray scattering study, Colloid Polym. Sci., 261, 271, 1983. Richter, M., Schierbaum, F., Augustat, S., and Knoch, K-D., Process for the production of starch hydrolysis products, U.K. Patent 1, 423, 780, 1976a. Richter, M., Schierbaum, F., Augustat, S., and Knoch, K-D., Method of producing starch hydrolysis products for use as food addtivies, U.S. Patent 3,962,465, 1976b. Roller, S. and Dea, I.C.M., Starch hydrolysis products, European Patent Application 9 530 5834.4-2114, 1995. Roller, S. and Swinton, S., Enzymic modifications of starch, in Biocatalysis in the Food Industry, Law, B., Ed., Royal Society of Chemistry, in press, 1995. Roller, S. and Swinton, S., Enzymes and the food industry, Food Sci. Technol. Today, 4(2), 111, 1990. Roller, S., Swinton, S., Woods, L.F.J., Gibbs, P.A., Hart, R.J., and Dea, I.C.M., Enzymic hydrolysis of starch for the production of fat mimetics, Leatherhead Food Res. Assoc. Research Report No. 664, 1990, 25 pp. Schenk, F.W. and Hebeda, R.E., Eds., Starch Hydrolysis Products, VCH Publishers, New York 1992, 570 pp. Schenk, F.W. and Hebeda, R.E., Starch hydrolysis products: An introduction and history, in, Starch Hydrolysis Products, Schenk, F.W. and Hebeda, R.E., Eds., VCH Publishers, New York, 1992, 3. Schierbaum, F., Personal communication, 1991. Schierbaum, F., Reuther, F., Braudo, E.E., Plashchina, I.G., and Tolstoguzov, V.B., Thermodynamic parameters of the junction zones in thermoreversible maltodextrin gels, Carbohyd. Polym., 12, 245, 1990. Schierbaum, F., Richter, M., Augustat, S., and Radosta, S., Herstellung, Eigenschafteen und Anwendung gelbildeneder Starkehydrolysenprodukte, Dutsch. Lebensmitt. Rundsch., 73(12), 390, 1977. ,

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Setzer, C.S. and Racette, W.L., Macromolecule replacers in food products, Crit. Rev. Food Sci. Nutr. 32(3), 275, 1992. Sobczynska, D. and Setzer, C.S., Replacement of shortening by maltodextrin-emulsifier combinations in chocolate layer cakes, Cereal Foods World, 36, 1017, 1991. Specter, S.E. and Setzer, C.S., Sensory and physical properties of a reduced-calorie frozen dessert system made with milk fat and sucrose substitutes, J. Dairy Sci., 77 (3), 708, 1994. Swinkels, J.J.M., Sources of starch, its chemistry and physics, in Starch Conversion Technology, van Beynum, G.M.A. and Roels, J.A., Eds., Marcel Dekker, New York, 1985, 15. Swinton, S.J., Skinner, J.M., Roller, S., Hart, R.J., and Dea, I.C.M., The enzymic improvement of starch functionality, in, Proc. Conf. Food Ingredients Eur., Expoconsult Publishers, Maarssen, Netherlands, 1990, 53. Takayanagi, M., Harima, H., and Iwatay, Y., Visco-elastic behaviour of polymer blends and its comparison with model experiments, Mem. Fac. Eng. Kyusha Univ., 23, 1, 1963. Whistler, R.L., BeMiller, J.N., and Paschall, E.F., Eds., Starch Chem. Technol., Academic Press, Orlando, FL, 2nd ed., 1984. Yackel, W.C. and Cox, C.L., Application of starch-based fat replacers, Food Technol., 46(6), 146, 1992. Zallie, J.P. and Chiu, C.-W., Imitation cheeses containing enzymatically debranched starches in lieu of caseinates, U.S. Patent 4,937,091, 1990. Zobel, H.F., Starch: Sources, production and properties, in Starch Hydrolysis Products, Schenk, F.W. and Hebeda, R.E., Eds., VCH Publishers, New York, 1992, 23.

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Chapter

6B

Starch-Derived Fat Mimetics from Potato Jaap Harkema CONTENTS 6B.1 6B.2 6B.3 6B.4 6B.5 6B.6

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties Interactions with Other Food Ingredients Applications 6B.6.1 Powdered and Liquid Foods 6B.6.2 Frozen Desserts 6B.6.3 Spoonable Products 6B.6.4 Spreadable Products 6B.6.5 Baked Goods 6B.7 Nutritional And Toxicological Aspects 6B.8 Legislative And Labeling Status References

6B.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Maltodextrins are hydrolyzed starch products obtained by the enzymatic conversion of starch. The degree of hydrolysis, expressed in dextrose equivalents (DE) determines to a large extent the characteristics of the product. In this part of the chapter, low-DE (DE < 5) maltodextrins prepared from potato starch and used as fat mimetics are described. Low-DE maltodextrins based on potato starch, as all maltodextrins, are cold soluble and have low viscosity in solution, but at high concentrations (> 20% w/w) they are unstable and form gels. These gels have a plastic, spreadable, shortening-like texture, which makes them suitable for use as fat mimetics. These gel forming properties have been claimed

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to be unique for maltodextrins based on potato starch (Richter et al., 1976). For a more detailed discussion of the literature on the physical properties of a wide range of maltodextrins used in fat replacement, refer to Chapter 6A. The chemical composition of potato starch with its low lipid and protein content makes it particularly attractive as a raw material for the preparation of bland maltodextrins for many food applications, including fat replacement. In addition, potato starch contains amylose molecules with longer chains (DP 3,000) than those found in corn and wheat starches (DP 800) and these are thought to retrograde less readily, thereby reducing the tendency to cause turbidity and an undesirable texture (Swinkels, 1985). Maltodextrins have been available to the food technologist as filling and bulking agents for many decades. The products are easily digestible, easy to blend with other dry ingredients, easy to dissolve, and have low viscosity in solution. When consumer concern with regard to the effect of too much fat in the diet on health started growing in the mid-1980s, maltodextrins, and more particularly low-DE maltodextrins, were “rediscovered” because of their excellent ability to mimic the functional properties of fat and oil. Furthermore, one part of a low-DE maltodextrin and three parts of water can often replace four parts of fat or oil. This can reduce the calories originally provided by fat to as little as 11%. However, it must be noted that in very few cases can all of the fat or oil in a formulation be substituted by low-DE maltodextrins without changing the texture and flavor characteristics of the food substantially. In many such cases, combinations with other functional ingredients (e.g., thickeners, emulsifiers) are required. One of the first low-DE maltodextrins to be launched on the market in the mid-1980s specifically for fat replacement has been Avebe’s Paselli SA2 derived from potato starch, followed in 1994 by Paselli Excel, a premium quality, flavor-free fat replacer developed specifically for delicately flavored foods. Meanwhile, other companies, such as Cerestar (Gruppo Feruzzi) and Roquette Frères are also marketing low-DE potato maltodextrins known as C*Pur 01906 and Lycadex® 100, respectively, for fat replacement applications.

6B.2 PRODUCTION PROCESS AND PATENT STATUS The production process for low-DE potato maltodextrins is relatively simple: a concentrated starch slurry is solubilized by jetcooking, the starch solution is enzymatically converted until the desired degree of hydrolysis (DE) is achieved, the enzyme is inactivated by either heat or a reduction in pH, and the product is spray-dried. A generalized scheme for maltodextrin production has been described in more detail in Chapter 6A. Although there are several process patents in the field associated with specific types of hydrolyzed starches with specific functionalities, the process of enzymic conversion of starch has been known for many years as part of glucose syrup production. Commercially available potato maltodextrins such as Paselli SA2 and Paselli Excel from Avebe have been produced using this generalized production method except that Paselli Excel has been subjected to additional purifying steps to remove all traces of off-flavors.

6B.3 CHEMICAL COMPOSITION Since starch is a polymer of branched and linear chains of glucose molecules, most maltodextrins are composed of similar building blocks. In addition to consisting largely of higher saccharides (997 mg/g), a potato maltodextrin with a DE of 2 to 3 usually also contains very small amounts of degradation products including glucose (<1 mg/g), maltose (1 to 2 mg/g) and maltotriose (2 mg/g). A typical example of a commercially available potato maltodextrin with this composition is Avebe’s Paselli SA2, available, like all other commercial maltodextrins, as an off-white powder. Paselli Excel has the

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same chemical composition and properties as Paselli SA2, but is entirely flavor-free. The composition of Cerestar’s potato-derived C*Pur 01906 is similar with a DE of 3 and a carbohydrate composition of 1% glucose, 2% of maltose and maltotriose each, and 95% higher saccharides. Specifications for another potato product, Lycadex® 100 from Roquette Frères, state that this enzymically hydrolyzed maltodextrin has a maximum DE of 5 and a carbohydrate composition of 0.5% glucose, 0.5% maltose, and 99% higher polysaccharides.

6B.4 PHYSICAL AND FUNCTIONAL PROPERTIES Low-DE maltodextrins derived from potato starch are free-flowing white powders with a bland flavor and generally have a bulk density of around 300 to 450 kg per m3. They are easily blended with the other dry ingredients. Maltodextrins are easy to dissolve in cold water, are clear in solution and provide, even at very high concentration, low viscosity. The viscosity depends however, on the degree of hydrolysis (DE). Low-DE maltodextrins have higher viscosity than their higher-DE counterparts as shown in Figure 6B.1.

Figure 6B.1 Effect of DE on the viscosity of three maltodextrin solutions at 40% dissolved solids with increasing temperature. Data were obtained using a Brookfield Viscometer. (From Avebe Company Brochure, Veendam, The Netherlands, 1993. With permission.)

As correct preparation of a maltodextrin gel is of some importance in achieving optimal functional performance, the detailed method is described here. For a 25% potato maltodextrin gel, 375 g of cold tap water is placed into a 600 ml glass beaker. The beaker is placed under a mixer with a propeller-type stirrer (e.g., Janke and Kunkel). The mixer is started on medium to high speed (approximately 1500 rpm) and 125 g of maltodextrin is added slowly by sprinkling it into the vortex, until a smooth, lump-free, opaque solution of low viscosity is obtained. The opacity is caused by small air bubbles. If available, the

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solution can be deaerated by placing it into an ultrasonic waterbath to give a clear solution with a layer of foam on top. Ultrasonication is a good way of ensuring that the maltodextrin has been fully dissolved. However, deaeration is not necessary for good gel formation as the air bubbles do not affect gel strength. After covering and refrigerating overnight, a white, smooth, and spreadable gel ready for further processing is obtained. Maltodextrin gels derived from potato starch have plastic, fat-like characteristics. The texture is short, spreadable, and nonelastic in nature and the gels are thermoreversible, which means that they melt upon heating and reset to a comparable gel strength when cooled down again. The gels are also shear-thinning and reform when shearing is stopped. Maltodextrin gels are pH-stable, retaining the same gel strength in the pH range 3 to 7. Gel strengths increase with higher concentrations, as shown in Figure 6B.2. The hydration temperature is also of interest; when the product is dissolved in hot water, the gel is stronger, as shown in Figure 6B.3. However, if higher water temperatures are used, more vigourous homogenization might be required as lumps may appear more quickly in hot than in cold water.

Figure 6B.2 Effect of maltodextrin concentration on the gel strength (g/mm) of a low-DE potato maltodextrin gel. Data were obtained using a Stevens Texture Analyzer. (From Avebe Company Brochure, Veendam, The Netherlands, 1993. With permission.)

Low-DE maltodextrins can be used directly as powders or in the form of pre-prepared gels, depending on the processing conditions and the desired characteristics of the final product. In either case, low-DE maltodextrins enhance creaminess, provide body, and give a fatty mouthcoating to the food product in which they are used. Examples of applications where low-DE maltodextrins exhibit these functionalities particularly well are cream soups and sauces, frozen desserts, and bakery fillings. Maltodextrins also often contribute to a fat-like (short, spreadable, or spoonable) texture, when the concentration in the available water in the formulation is sufficiently high for gel formation to take place. This property is particularly useful in products such as cheesecake or low-fat spreads.

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Figure 6B.3 Effect of hydration temperature on gel strength (g/mm) of a low-DE potato maltodextrin. Data were obtained using a Stevens Texture Analyzer. (From Avebe Company Brochure, Veendam, The Netherlands, 1993. With permission.)

6B.5 INTERACTIONS WITH OTHER FOOD INGREDIENTS Interactions between native starches and lipids in food products are also manifested in products containing potato maltodextrins and lipids. Trials using a model system with combinations of Avebe’s potato-derived Paselli SA2 and different emulsifiers have shown that the presence of certain emulsifiers increased the rate of gel formation (Table 6B.1), gave better control of the final gel strength, and modified the final gel textures. The model results were confirmed in a study of chocolate layer cakes in which the shortening was replaced by a combination of a low-DE potato maltodextrin and emulsifiers (Sobczynska and Setzer, 1991). The best results were obtained using sucrose-ester- or monoglyceride gels in combination with low-DE potato maltodextrin added in the dry form. The exact mechanism of the interaction is unknown, but it is believed that helical inclusion complexing occurs between linear fractions of Paselli SA2 and the fatty acid chains of the emulsifiers. Another ingredient interaction of importance in food products is the effect of maltodextrins on the viscosity of native starch. As shown in the Brabender viscograph in Figure 6B.4, the peak viscosity of a native potato starch solution decreases somewhat in the presence of free glucose; however, in the presence of maltodextrins, the effect is much more pronounced. Furthermore, the lower the DE of the maltodextrin, the larger the effect (Figure 6B.4). It is believed that the sugars in the maltodextrin compete with the starch for the available water thereby inhibiting the swelling of the native starch granules. In this way, the native starch starts behaving like a chemically crossbonded starch; the swelling is delayed and the viscosity peak disappears. This means that the addition of maltodextrin could be used in some applications to stabilize the viscosity of native potato starch.

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Table 6B.1 Effect of Emulsifiers on the Rate of Gelation of a Low-DE Potato Maltodextrin, Paselli SA2, Using Stevens Texture Analyzer Readings Ingredients

Gel strength at 1 h (g/mm)

Gel strength at 24 h (g/mm)

No addition + SSL 3% + SE 3% + GMS 3%

Liquid 147 108 20

79 221 207 89

Note: SSL = Sodium Stearoyl Lactylate (Admul SSL-2004, Quest); SE = Sucrose Ester (S-1670, Mitsubishi-Kasei); GMS = Glycerol mono-stearate (Myverol 18-06, Kodak Eastman).

Figure 6B.4 Effect of free glucose (dextrose) and two maltodextrins (DE 20 and DE 2-3) on Brabender viscosity of native potato starch. (From Avebe Company Brochure, Veendam, The Netherlands, 1993. With permission.)

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6B.6 APPLICATIONS In the following section, the use of low-DE maltodextrins in a range of specific food product sectors is discussed and illustrated using formulations containing some of the commercially available maltodextrins, including Paselli SA2 (Avebe), Paselli Excel (for delicately flavored foods) and C*Pur 01906 (Cerestar). The Paselli range of fat replacers is recommended for use in soups, sauces, dressings, dips, dairy applications, and bakery products (cakes, frostings). Cerestar’s C*Pur 01906 is recommended for use in salad dressings (hot and cold produced), low-fat spreads, ice cream, and meat products (De Coninck, 1993). Roquette Frères’ Lycadex® 100 is also available and is recommended for use in applications where solid fat (e.g., shortening, butter, margarine) has to be replaced or where the fat replacer has to contribute to a creamy, plastic, or spreadable texture, as in salad dressings, cooked meats, low-fat spreads, cheeses, and ice cream (Roquettes Frères, 1991). 6B.6.1 POWDERED AND LIQUID FOODS The most obvious application by direct addition of spray-dried low-DE maltodextrins is in powdered products such as instant soups. Once the dried food product has been dissolved, the presence of low-DE maltodextrins enhances creaminess, adds body and texture, and gives a fatty mouthfeel to the food product. In liquid foods such as soups, sauces, desserts, pourable dressings, creamers, and beverages, it is recommended that low-DE maltodextrins are added to the dry ingredients in the formulation before the addition of water. In these systems, low-DE maltodextrins add to a full-bodied texture and mouthcoating, since their viscosity is relatively high compared with higher-DE maltodextrins. Because of the relatively low concentrations of maltodextrins used (1 to 5%) and the fact that the continuous water phase is large, gels are not formed. An example of this use of low-DE maltodextrins is shown in the formulation and preparation procedure for low-fat butter sauce in Table 6B.2. The preparation procedure for this food product involves blending together all the dry ingredients, placing the dry ingredients into water in a sauce pan, bringing the mixture to the boil while stirring constantly, reducing to a simmer and cooking for 5 to 7 min while stirring.

Table 6B.2 Use of a Low-DE Potato Maltodextrin, Paselli Excel, in a Low-Fat Butter Sauce Ingredients Water Modified potato starch1 Paselli EXCEL Cultured butter powder2 Non-fat dry milk Salt Marjoram Chives Basil Pepper Total 1 2

% 88.55 3.20 2.50 2.40 2.00 1.00 0.15 0.10 0.05 0.05 100.00

Farinex VA20, AVEBE. J-02C, Commercial Creamery Co.

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Nutritional information Product

Calories/ 100 g

Calories from fat

Total fat (g)

Control Low-fat

59 46

40.5 15.3

4.5 1.7

6B.6.2 FROZEN DESSERTS As for powdered and liquid foods, dry addition of low-DE maltodextrins to the formulation for frozen desserts is recommended. Although concentrations used may be comparable to those suitable for liquid foods, the functionality of low-DE maltodextrins may be higher in frozen foods. Since all water-soluble components are dissolved in the nonfrozen water phase, a concentration effect may occur which, in turn, enhances the functionality thereby improving the creaminess, fat-like texture, and firmness of bite. An example of the application of low-DE maltodextrins in a low-fat soft serve frozen dessert is given in Table 6B.3. The frozen dessert is prepared by blending all the dry ingredients together, blending the wet ingredients separately, and then adding the dry ingredients to the wet mix, pasteurizing at 74°C, homogenizing at 200 psi, adding flavor and running the mix through a soft-serve machine.

Table 6B.3 Use of a Low-DE Potato Maltodextrin, Paselli Excel, in a Low-Fat Soft Serve Frozen Dessert Ingredients Whole milk (3.25% fat) Sugar Corn sirup 42 DE Skim milk Non-fat dry milk Whey powder Paselli EXCEL Stabilizer1 Flavor Total 1

% 67.70 11.00 7.64 6.01 3.02 2.63 1.50 0.50 qs 100.00

Nutritional information Product

Calories/ 100 g

Calories from fat

Total fat (g)

Control Low-fat

202 136

96.75 20.88

10.75 2.32

Kontrol, Germantown Mfg. Co.

6B.6.3 SPOONABLE PRODUCTS Spoonable products such as emulsified sauces and mayonnaise are oil-in-water emulsions. Therefore, as in frozen dessert applications, there is a concentration effect; the fat replacer, being entirely in the water phase of the product, is more functional than it would seem from the final concentration. This is beneficial in terms of mouthfeel and creaminess, but could have drawbacks regarding texture. The gel forming properties may cause an undesirable, gellified, cuttable consistency. However, the occurrence of this negative effect depends on the concentration of the maltodextrin used, the total fat content of the product, the other ingredients in the formulation, and the processing conditions selected. In most cases, these parameters can be adjusted and many customers use low-DE maltodextrins in spoonable dressings without any problems. An example of the application of a low-DE potato maltodextrin in a low-fat salad dressing is given in Table 6B.4. The manufacturing process involves preparing a cold slurry of sucrose, pepper, salt, C*Flo 06205, C*Pur 01906, C*Pur 01934, and preservatives in the water and vinegar, heating the slurry to 85°C and maintaining this temperature for 5 min, cooling to 20 to 25°C, feeding the starch paste and egg yolk (powder previously hydrated in water and deducted from the total amount of water added) into a FRYMA colloid mill, homogenizing the mix for 30 s, adding the mustard and oil wherein the hydrocolloids have been dispersed, emulsifying for a further 15 s, and filling into glass jars for storage at room temperature.

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Table 6B.4 Use of a Low-DE Potato Maltodextrin C*Pur 01906 in a Hot-Prepared Reduced-Fat Salad Dressing Containing 25% Oil Ingredient Sunflower oil Egg yolk (powder) Xanthan gum Guar gum Starch paste (“Kuli”)1 Mustard Essential mustard oil Water

Content (%) 25 1.82 0.03 0.12 68 2 0.0025 3.0275

1

Starch paste composition: Modified starch C*Flo 06205, Cerestar Spray dried maltodextrin C*Pur 01906, Cerestar Spray dried glucose syrup C*Pur 01934, Cerestar Salt Sucrose (or dextrose, Cerestar CL 02001) Pepper flavor Vinegar 13º Lactic acid (80% sol.) Sodium lactate Potassium sorbate Water From De Coninck, 1993, Cerestar Company Brochure, With permission.

4.5 1 10 1.5 2.5 0.06 5.06 0.53 1.32 0.067 40.463 Belgium.

6B.6.4 SPREADABLE PRODUCTS Spreadable products include such foods as table spreads, meat pâtés, frostings, and cheesecake. When the fat content of such products is lowered, the continuous oil phase becomes smaller and the water phase larger. Therefore, thickening of this water phase is necessary to stabilize the system. For this group of products, the gel-forming properties of lowDE maltodextrins are required and are very beneficial. Since the gel has a short, spreadable texture, low-DE maltodextrins are widely used as fat replacers in this group of products. They can be added as a preformed gel to give additional texture during processing, but they can also be added dry; the concentration used in conjunction with the available formulation water and the other stabilizers guarantees the formation of a gel in the final product. The use of pre-prepared maltodextrin gels in reduced-fat cheesecake is illustrated in Table 6B.5. The manufacturing procedure involves the preparation of a 25% solution of Paselli SA2 followed by storage overnight in a refrigerator, mixing the cream cheese, Paselli SA2 gel, and sugar on medium speed for 2 min, incorporating sour cream until blended, pouring into a spongiform pan, baking at 350°F for 60 min in a Bain-Marie, cooling in the oven, and refrigerating. 6B.6.5 BAKED GOODS The use of preformed maltodextrin gels is recommended for baked food products. When the fat content of a batter or dough is lowered, viscosity decreases. This hampers the entrapment of air which is normally an important function of shortening. Maltodextrin gels increase dough viscosity and improve aeration.

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Table 6B.5 Use of a Low-DE Potato Maltodextrin, Paselli SA2, in a Low-Fat Cheesecake Ingredients

%

Low-fat cream cheese (Neufchatel) Paselli SA2 Gel (25%) Sugar No-fat sour cream Whole eggs Pure vanilla extract Total

28.53 28.32 18.02 15.33 9.50 0.30 100.00

Nutritional information Product

Calories/ 100g

Calories from fat

Total fat (g)

Control Low-fat

302 208

172.6 83.7

19.18 9.3

6B.7 NUTRITIONAL AND TOXICOLOGICAL ASPECTS Low-DE maltodextrins, including Avebe’s Paselli SA2, are fully digestible and provide, like all digestible carbohydrates, 4 kcal/g. The pre-prepared gels, consisting of one part maltodextrin and three parts water, have only 1 kcal/g which is only 1/9 of the caloric value of fats and oils. Since low-DE maltodextrins are made from slightly degraded starch and do not constitute novel chemical entitites, no specific toxicological studies have been necessary. Nutritional studies showing the effect of using maltodextrins as fat replacers on fat and calorie intake are scarce. However, a recent study using rats has shown that the use of Paselli SA2 as a fat replacer in reduced-fat foods was effective in achieving an overall reduction in fat intake in the diet (Harris, 1994). Further discussion of the results of the Harris study can be found in Chapter 2. The use of complex carbohydrates, such as potato maltodextrins, to replace fats and oils in the diet has been strongly recommended by many national and international medical organizations.

6B.8 LEGISLATIVE AND LABELING STATUS Maltodextrins are all-natural food ingredients that have not been chemically modified. In Europe, they are allowed for use in foods as food ingredients and are not classified as food additives; therefore, they have no E-number in European countries. In the U.S., maltodextrins are approved direct food substances (FDA CFR 21, 1983). In 1995, the FDA affirmed the GRAS status of maltodextrin derived from potato starch as a direct human food ingredient. Maltodextrins such as Avebe’s Paselli SA2 can be labeled as either “starch” or “maltodextrin,” depending on local food legislation. These regulations are in contrast to those pertaining to certain chemically modified food starches which are also marketed as fat replacers, e.g., A.E. Staley’s Sta-Slim™ range, which need to be labeled as “modified starch” when used in a reduced fat food product. There are no limits to the concentrations of maltodextrins allowed in foods. For some food categories in some countries, so-called vertical regulations exist. This means that certain limitations in certain kinds of food products may apply. For example, the use of low-DE maltodextrins in reduced-fat ice cream formulations is allowed, but the resulting food product cannot be called “ice cream” and must be renamed as, for example, “frozen dessert.”

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REFERENCES Avebe, Paselli SA2, The Proven Fat Replacer, Company Brochure, Veendam, The Netherlands, 1993. De Coninck, V., Fat Reduced Foods with C*Pur 01906, Company Brochure, Cerestar, Belgium. Food and Drug Administration, Code of Federal Regulations, Title 21, Office of the Federal Register, National Archives and Records Administration, Washington, D.C., Paragraph 184.1444, 1983. Harris, R.B.S., Factors influencing energy intake of rats fed either a high-fat or a fat mimetic diet, Int. J. Obesity, 18, 632, 1994. Richter, M., Schierbaum, F., Augustat, S., and Knoch, K-D., Assignee Academy of Sciences of the German Democratic Republic, Method of producing starch hydrolysis products for use as food additives, U.S. Patent 3 962 465, 1976. Roquettes Frères, Lycadex, The Natural Choice for Light Products, Company Brochure, Lestrem, France, 1991. Sobczynska, D. and Setzer, C.S., Replacement of shortening by maltodextrin/emulsifier combinations in chocolate layer cakes, Cereal Foods World, 36(12), 1017, 1991. Swinkels, J.J.M., Sources of starch, its chemistry and physics, in Starch Conversion Technology, van Beynum, G.M.A. and Roels, J.A., Eds., Marcel Dekker, New York, 1985, 15.

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Chapter

7A

Fiber-Based Fat Mimetics: Microcrystalline Cellulose William M. Humphreys CONTENTS 7A.1 7A.2 7A.3 7A.4 7A.5 7A.6

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties Interactions with Other Food Ingredients Applications in Foods 7A.6.1 Applications of Powdered Grades of Microcystalline Cellulose 7A.6.2 Applications of Colloidal Grades of Microcystalline Cellulose 7A.6.3 Salad Dressings 7A.6.4 Processed Cheese 7A.6.5 Frozen Desserts 7A.7 Nutritional and Toxicological Aspects 7A.8 Legislative and Labeling Status References

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7A.1 INTRODUCTION AND HISTORICAL PERSPECTIVE In June 1961, a Life Magazine article entitled “Food That Isn’t Food,” announced that Dr. Battista from the American Viscose Corporation had invented a miraculous gel from microcrystalline cellulose, trade named Avicel®. The article further confided that Myra Waldo, a well established author of cookbooks, had been retained to design new recipes worthy of microcrystalline cellulose containing products for the supermarket. “Nearly 1,000 food firms across the country have sent for samples,” Life reported, “and within their heavily guarded test kitchens are striving to gain lead time on their competitors … By late summer the first non-food product may be on the shelves.” (Wyden and Morrow, 1965). Over the course of 34 years the Avicel® microcrystalline cellulose product line has been expanded and improved. The powdered grades were the first to be developed in 1957. Avicel® PH 101, originally developed for use in low-calorie food products, found wider acceptance within the pharmaceutical industry as a tableting aid and for use in direct compression. Since then, numerous powdered grades of microcrystalline cellulose have been developed for use in foods and are primarily used as zero calorie bulking agents and freeflow agents (FMC Corp., 1993a). Two families of powdered microcrystalline cellulose products, the FD (e.g., Avicel® FD100) and LM (e.g., Indulge® LM310) grades, were also specifically developed for use in low-fat applications. The first colloidal grade of microcrystalline cellulose was developed in 1964 but had a rather limited functionality, and it was not until a year later that a more functional grade was developed which today is widely used in the dairy and frozen dessert industry (Reilly, 1994). A family of colloidal microcrystalline cellulose products was launched in 1978 based on co-processing microcrystalline cellulose with sodium carboxymethyl cellulose. These products are dispersed (activated) with homogenization or high shear mixing and are now used in the food industry as stabilizers and fat replacers in a myriad of food products. A very recent addition to the colloidal microcrystalline cellulose product range are the Avicel® AC grades, based on co-processing with alginates (FMC Corp., 1994a). The AC grades have been developed for applications where the functional properties of colloidal microcrystalline cellulose are required but processing or other factors inhibit its use and in applications where the functionality of the alginate component is desired. The AC products are easily dispersed with low shear and are ideal for use in dry blends. Other colloidal products include MicroQuick® and MaltoQuick® based on co-processing with whey and maltodextrin, respectively. These products are readily dispersed and are primarily used in applications such as dry powder mixes where shear and/or moisture levels are limited (FMC Corp., 1993a). In the late 1980s, consumer demand for lower and lower fat levels in foods with no compromise in eating qualities led to the development of the Novagel™ range of fat mimetics. In many ways complimentary to the colloidal products, these microcrystalline cellulose/guar gum aggregrates hydrate to form soft, spherical particles which are physically very similar to fat globules, but have no caloric value. These fat mimetics are suitable for use in any aqueous based food product where a fat like consistency, mouthfeel, and appearance is desired (FMC Corp., 1994b).

7A.2 PRODUCTION PROCESS AND PATENT STATUS The raw material for the production of microcrystalline cellulose is a selected refined a cellulose. The microfibrils which make up the α cellulose are composed of paracrystalline and crystalline regions (FMC Corp., 1993a). The paracrystalline area is an amorphous

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mass of cellulose chains and the crystalline region comprises tight bundles of microcrystals in a rigid linear arrangement. The first step in the process is acid depolymerization which removes the amorphous chains and leaves crystalline bundles of cellulose. The production process at this point can take one of two routes, resulting in powdered or colloidal microcrystalline cellulose as shown in Figure 7A.1 (FMC Corp., 1993a). Utilizing a proprietary agglomeration and drying step, it is possible to produce aggregates of very porous particles of powdered microcrystalline cellulose (FMC Corp., 1993a).

Figure 7A.1 Steps in the production of microcrystalline cellulose products. (From FMC Corporation, Philadelphia, PA, 1994b. With permission.)

The colloidal products are manufactured by applying intense shear forces to break open the cellulose network to form colloidal microcrystalline cellulose. To prevent the colloidal material from reaggregating during drying, a soluble hydrocolloid is introduced. This acts as a barrier coating for particles and facilitates water uptake and dispersion. The characteristics of the soluble hydrocolloid has an effect on the properties of the dispersed product, which together with different drying techniques, give the range of commercial products shown in Table 7A.1. The manufacturing process for Novagel™ microcrystalline cellulose aggregrates follows the same initial steps. The cellulose microcrystals are co-processed with guar gum which exhibits a strong affinity for the microcrystalline cellulose. This produces a guar coating of the pliable microcrystalline cellulose spheres (McGinley and Tuason, 1993) which imparts the “slipperiness” that is similar to the sensory properties of fat in food products (Table 7A.2). The material is then dried in a manner to ensure a regular particle size when dispersed in water. There are currently over 150 U.S., German, Japanese, European, Dutch, Belgian, and French patents pertaining to the development and use of microcrystalline cellulose. Patent categories cover general product technology, bakery and dessert products, beverages, sauces and salad dressings, confections and jelly products, instant powder applications, formed and extruded foods, microwave applications, low-calorie/low-fat, and miscellaneous applications.

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Table 7A.1 Key Physical and Chemical Properties of Colloidal Grades of Avicel® Microcrystalline Cellulose Avicel® RC501

Properties MCC Content (%) Process

91 Bulk-dried

Avicel® RC 581 89 Bulk-dried

Equipment required to Homogenizer Homogenizer activate Use levels in foods (%) 0.5–3 0.3–0.8 Initial viscosity (cP*) 72–168 72–168 at 2.1% at 1.2% Set-up viscosity (cP**) 1025 1125 at 2.1% at 2.1% Primary uses Whipped Frozen toppings, desserts heat-stable emulsions

Avicel® RC 591F 88 Spray-dried

Avicel® CL611

Avicel® RCN30

0.3–1 39–175 at 1.2%

75 85 Co-processed Co-processed with with xanthan calcium alginate and maltodextrin High speed mixer High speed mixer High shear or low shear with sequestrants 0.2–2.5 0.5–1.5 0.4–2.5 50–151 at 2.6% 620 at 3% n/a

1250 at 1.2%

1850 at 2.6%

General stabilizer, thixotropic gels

Pourable systems Stabilizer, frozen desserts

High speed mixer

85 Spray-dried

n/a

Note: MCC = Microcrystalline cellulose. * = Initial viscosity was measured at 120 s, using a Brookfield RVT Viscometer No. 1 Spindle at 20 rpm. ** = Set-up viscosity was measured at 24 h as above but using a No. 3 Spindle at 20 rpm.

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Avicel® AC815

MicroQuick WC595

MaltoQuick MC230

22 Co-processed with whey

22 Co-processed with maltodextrin Low shear

Low shear

2–4 2–4 10–100 at 6% 50–150 at 5%

n/a

1200 at 6%

Stabilizer, dry blended or low shear foods

Dry blended foods

Dry blended foods

Table 7A.2 Key Physical and Chemical Properties of Novagel™ Grades of Microcrystalline Cellulose Properties

Novagel™ RCN 10

Novagel™ RCN 15

Microcrystalline cellulose content (%) Shear required to activate Physical form Use levels in foods (%) Key applications

90 Low Pliable spheres 0.3–3 Frozen desserts, cheese, and beverages

85 Medium Spongy spheres 0.3–5 Salad dressings, icings, frostings, cheese, and beverages

Modified from FMC Corp., 1994b. With permission of the FMC Corporation, Philadelphia, PA.

7A.3 CHEMICAL COMPOSITION Microcrystalline cellulose is a purified, naturally occurring fraction of cellulose, the most abundant natural polymer on earth. It is composed of anhydroglucose units linked together through a β (1–4) glycosidic bond (FMC Corp., 1993a). It is a hydrophilic, water insoluble, linear, high molecular weight polymer consisting of ordered, crystalline areas. In commercial colloidal grades and aggregrate grades, microcrystalline cellulose comprises 75 to 95% by weight of the composition. The remaining 5 to 20% is a soluble hydrocolloid, the type and level varying between different products, as shown in Table 7A.1. Sodium carboxymethyl cellulose, the soluble component in RC/CL colloidal grades, is an anionic water-soluble polymer derived from cellulose. The AC colloidal grades of microcrystalline cellulose are co-processed with calcium alginate, a structural polymer composed of mannuronic and guluronic acids, extracted from the cell walls of brown seaweeds (Imeson, 1994). RCN aggregrate grades are co-processed with guar gum, a galactomannan extracted from plant seeds and composed of a mannose backbone with galactose side-chains. In these co-processed products, the soluble hydrocolloids are associated with the microcrystalline cellulose by hydrogen bonds to give an integrated structure. Different products contain different levels and specific types of each hydrocolloid depending on the targeted application and desired properties.

7A.4 PHYSICAL AND FUNCTIONAL PROPERTIES Commercial forms of microcrystalline cellulose are sold as free flowing white powders. Powdered grades of microcrystalline cellulose are insoluble and chemically inert; they are crystalline in nature and, as shown in Figure 7A.2, very porous (FMC Corp., 1993a). Unlike the powder grades, the colloidal grades of microcrystalline cellulose exhibit specialized rheological characteristics which impart unique functional properties. When dispersed in water using sufficient shear, the microcrystalline cellulose particles form a microscopic three dimensional (3-D) network of crystals, as shown in Figure 7A.3. The coprocessed soluble hydrocolloids facilitate the formation of this network by acting as water swelling capillaries between the crystals, forcing them to open during hydration. This network is then stabilized by hydrogen bonding between the polar groups on the surface of the cellulose. The soluble hydrocolloids also function to consolidate the network through hydrogen bonding to the microcrystalline cellulose (FMC Corp., 1989a). This network imparts a unique rheology and structures water in a completely different manner from soluble gums and thickeners. The forces holding the network together are shear-sensitive and break down readily. When the shear is removed, the 3-D network quickly reforms giving microcrystalline cellulose dispersions marked thixotropic properties. The microcrystalline cellulose network also demonstrates a yield stress and, very

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Figure 7A.2 Scanning electron micrograph of a particle of powdered microcrystalline cellulose. (From FMC Corporation, Philadelphia, PA, 1993a. With permission.)

Figure 7A.3 Scanning electron micrograph of a 3-D network of colloidal microcrystalline cellulose. (From FMC Corporation, Philadelphia, PA, 1993a. With permission.)

importantly, has a short texture. This thixotropic network of insoluble crystals is physically and functionally similar to the insoluble network of dispersed oil droplets in an oil-in-water emulsion and is the key to the unique functionality of colloidal microcrystalline cellulose in fat replacement. The properties of Novagel™ RCN are very different. Once dispersed in water, the particles of Novagel™ RCN exist in a substantially spherical form. Micrographs taken using a scanning electron microscope (SEM) show that Novagel™ RCN 10 forms firm, pliable, spherical particles while Novagel™ RCN 15 forms more open, deformable, spherical aggregates as shown in Figure 7A.4 (FMC Corp., 1994b). Consequently, Novagel™ RCN 10 has less surface area and lower water absorption properties (absorbing

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approximately 2.5 times its own weight) than Novagel™ RCN 15 which absorbs up to 10 times its own weight of water. Within food systems, these particles contribute a fatlike consistency, a creamy mouthfeel, body, and opacity. Novagel™ RCN is stable under a broad range of processing conditions: retort, UHT, freezing, and low pH including microbial fermentations, microwave, etc.

Figure 7A.4 Scanning electron micrograph of a particle of Novagel™ RCN 15. (From FMC Corporation, Philadelphia, PA, 1994b. With permission.)

7A.5 INTERACTIONS WITH OTHER FOOD INGREDIENTS Due to the inert nature of microcrystalline cellulose, there are no known notable interactions between it and other food ingredients. The soluble hydrocolloids in Novagel™ and colloidal Avicel®, however, interact as typical for these substances but to a lesser degree due to their close association with the surface of the microcrystalline cellulose crystals, limiting the surface area and active sites available for interaction.

7A.6 APPLICATIONS IN FOODS It is possible to mimic some or all of the mouthfeel, opacity, consistency, and body contributed by fat in a vast array of food products using one or a combination of microcrystalline cellulose based ingredients. The food products where Avicel® and Novagel™ microcrystalline celluloses are most frequently used as fat replacers include salad dressings, bakery products, dairy products, ice cream and frozen desserts, cheese, spreads, and processed meats. The quantity of microcrystalline cellulose required depends on the amount and type of fat being replaced and the nature of the food product. Usage levels can range from 0.1 to 10.0% but standard use levels are from 0.4 to 3.0%. In most food systems, microcrystalline cellulose is used as part of an overall fat-mimetic system, which often includes soluble hydrocolloids, starch, fat flavors, and antimicrobial agents.

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7A.6.1 APPLICATIONS OF POWDERED GRADES OF MICROCRYSTALLINE CELLULOSE Powdered grades of microcrystalline cellulose are commonly used in foods as a high quality inert fiber source and a noncaloric bulking agent. Additionally, the porous and free-flowing nature of these products make them ideal as carriers of liquid materials such as essential oils. They are also widely used as anticaking agents in grated cheese. Two families of powdered microcrystalline cellulose products, the FD and LM grades, were specifically developed for use in low fat applications. FD products (e.g., Avicel® FD100) can be used in reduced-fat aqueous based foods as a noncaloric source of insoluble solids, imparting much of the body and opacity usually contributed by fat. The FD range has a clean flavor release with no significant flavor contribution or flavor masking properties. The LM grades of powdered microcrystalline cellulose (e.g., Indulge® LM310) were specifically developed to meet the challenge of producing reduced-fat/calorie products that are also low in moisture, such as confectionery products and biscuit fillings. Due to water activity limitations in such food products, structured water cannot be used as a direct replacement for fat as is the practice with emulsion systems. Low moisture applications require high levels of non or low calorie bulking agents to achieve a sufficient calorie/fat reduction. In the manufacture of Indulge™ LM, a new technology has been pioneered to reduce the porosity and surface area of the particle so that absorption properties are reduced. LM grades can be used at levels of up to 15% and, often in conjunction with sugar syrups, function as a high quality replacement for fat and/or sugar in most foods where moisture levels are restricted. 7A.6.2 APPLICATIONS OF COLLOIDAL GRADES OF MICROCRYSTALLINE CELLULOSE The key to obtaining optimal functionality from colloidal grades of microcrystalline cellulose is in the correct activation of the product in foods by the creation of a three dimensional gel network. The appearance (under a microscope) of a correctly and fully dispersed network is shown in Figure 7A.5. This dispersion is formed by the action of shear forces. The nature of the shear forces required to create an effective functional dispersion depends on the grade of Avicel® used, as shown in Table 7A.1. Products are available for any unit operation from high pressure homogenization to simple dry blends. A number of key factors may interfere with the proper dispersion of colloidal microcrystalline cellulose. First, adequate shear must be used, i.e., the shear regime of the process must match the requirements of the grade of microcrystalline cellulose selected. Second, the order of addition should be correct and ideally colloidal microcrystalline cellulose should be added to the water before other ingredients are added. Third, hard water/electrolytes can inhibit the dispersion of colloidal microcrystalline cellulose, so dispersion in water containing low levels of salt is recommended. Fourth, when acidifying a dispersion of microcrystalline cellulose to a pH below 4.5, a protective colloid is necessary to prevent flocculation. Most soluble gums have a protective effect but the most effective is xanthan gum at a level of approximately 10% by weight of Avicel®. In dry form, Novagel™ RCN exists as agglomerates of microcrystalline cellulose/guar and to achieve functionality these aggregrates must be separated from one another and dispersed evenly in the aqueous phase, as shown in Figure 7A.6. As with the Avicel® range, this is achieved by the action of shear forces (FMC Corp., 1994b). The quantity and nature of the shear forces necessary to achieve effective dispersion are dependant upon the aqueous phase viscosity and composition, the concentration and type of Novagel™ RCN, and the method of addition. Notably, it is usually independant of the aqueous phase temperature and pH.

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Figure 7A.5 Photograph of a fully dispersed colloidal Avicel® dispersion under polarized light and 100X magnification. (From FMC Corporation, Philadelphia, PA, 1994b. With permission.)

Figure 7A.6 Photograph of a Novagel™ dispersion under polarized light and 100X magnification. (From FMC Corporation, Philadelphia, PA, 1993a. With permission.)

As a general guideline for processing, medium levels of Novagel™, added either dry or as part of a dry blend with other food ingredients, are readily dispersed in water by applying such shear forces as those obtained using a propellor mixer at approximately 1600 rpm for 5 min. Even under minimum shear conditions, such as spoon-stirring in dry powder mix applications, much of the functionality of Novagel™ is exhibited. The amount of shear force necessary increases as the viscosity and/or solids level of the aqueous phase increases and as Novagel™ concentration increases. As microcrystalline cellulose based products do not significantly bind water, they will not prevent the solubilization or dispersion of ingredients added subsequent to their activation. In the same manner, they have little effect on the water activity (aw) of the food.

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Figure 7A.7 Viscosity of basic soybean oil emulsions with and without Avicel® as a function of shear rate. (From FMC Corporation, Philadelphia, PA, 1994b. With permission.)

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The addition of low percentages of colloidal microcrystalline cellulose to reduced-oil emulsions can confer properties that mimic those of high oil emulsions as shown in Figure 7A.7 (FMC Corp., 1993a). For example, the stability and rheological characteristics of a 65% soybean oil emulsion can be simulated with a 20% soybean oil emulsion when the dispersion includes 1.5% Avicel® CL 611. In addition to mimicking the flow properties of an emulsion, colloidal microcrystalline cellulose imparts much of the opacity and fat like mouthfeel of full-fat products. Unlike water soluble polymers, microcrystalline cellulose does not chemically bind water and temperature changes have little or no effect on the functionality and apparent viscosity of microcrystalline cellulose networks. These networks remain stable under high temperatures including those used during baking, retorting, UHT processing, and microwave heating with minimal loss in viscosity. Microcrystalline cellulose stabilizes foams and emulsions in food products by both structuring the water phase, maintaining the air cells and oil droplets in suspension, and by orientating somewhat at the oil and water and air and water interface, acting as a physical barrier to coalescence (FMC Corp., 1989). Microcrystalline cellulose networks are also very effective in suspending particulates. As mentioned previously, Novagel™ functions in a very different manner to colloidal microcrystalline cellulose. Once properly hydrated, Novagel™ forms soft, somewhat spherical particles which are physically similar to fat globules (Tuason, 1994). Manufactured in two key forms, Novagel™ RCN 10 and Novagel™ RCN 15 (Table 7A.2) are tailored to mimic the organoleptic properties of different physical forms of the fat type being replaced in the food (FMC Corp., 1994b). Novagel™ RCN 10 is most suitable for use in such applications as frozen desserts, processed cheese and low fat meats, while Novagel™ RCN 15 is most suitable for more fluid applications such as salad dressings, dairy beverages, etc. (FMC Corp., 1993b). 7A.6.3 SALAD DRESSINGS The replacement of fat in salad dressings is one of the most common applications of microcrystalline cellulose technology, as shown in Table 7A.3 (FMC Corp., 1993c). Formulated to match the organoleptic profile of an 80% fat mayonnaise, microcrystalline cellulose contributes a variety of properties. Avicel® functions as an effective emulsion stabilizer with thixotropic flow properties while both Avicel® and Novagel™ function to impart a full fat texture, appearance, mouthfeel, and body in low fat dressings. Typically, a rotor/stator is used to manufacture this type of product. Good quality water (particularly with low levels of positively charged particles) is placed in the milling chamber under a vacuum of 200 to 400 mbar and with scraped surface. The Avicel® CL 611 is introduced and milled at 3500 rpm for 3 to 4 min. A blend of Novagel™ RCN 15, xanthan gum, and sugar is added next and incorporated by milling further for 4 min. In order to increase plant throughput, these initial dispersion steps are often carried out in a premix tank using a high shear mixer. Adequate shear is essential: mixing for 5 to 10 min at a minimum of 1800 rpm is usually sufficient but the dispersion should be microscopically checked to ensure that the appropriate structure of the system has been obtained, as shown in Figure 7A.5. Starch is then added, either as a starch paste or in dry form if a pregelatinized starch is used. The egg yolk, salt, preservatives, mustard, and spices can then be added, followed by the oil while continuously milling. The vinegar and other acids are added last and the dressing may be pasteurized and hot or cold filled. An example of the rheological properties obtained from a no-fat salad dressing containing 4.5% Novagel™ RCN 15, compared with a full-fat control dressing is shown in Figure 7A.8.

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Table 7A.3 Use of Avicel® and Novagel™ in a Low-Fat Spoonable Dressing Containing 5% Fat Ingredients

%

®

1.8 1.4 4.3 0.3 3.6 5.8 4.0 4.5 0.5 1.8 qs to 100 100

Avicel CL 611 Novagel™ RCN 15 Vegetable oil Xanthan gum Modified waxy maize starch Sugar Egg yolk 12% Vinegar Lemon juice Salt Flavors and preservatives Water TOTAL

Modified from FMC Corp., 1993c. With permission of the FMC Corporation, Brussels, Belgium.

Figure 7A.8 Rheology of a full-fat salad dressing compared with no-oil dressings with and without Novagel™ RCN 15 added. (From FMC Corporation, Philadelphia, PA, 1993a. With permission.)

7A.6.4 PROCESSED CHEESE Microcrystalline cellulose technology is also commonly used in the manufacture of reduced-fat processed cheeses, both slice and block forms, as shown in Table 7A.4. (FMC Corp., 1994d). Containing less than 1% fat compared with over 30% fat in many processed cheeses, Novagel™ replaces most of the functions of the fat globules. In addition to contributing a full-fat mouthfeel, body, and opacity, Novagel™ functions to break the elastic protein structure which tends to form in the absence of fat. By breaking

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Table 7A.4 Use of Novagel™ RCN in a LowFat Processed Cheese Containing <1% Fat Ingredients Novagel™ RCN 10 Skim milk cheese Sweet whey powder Trisodium citrate Disodium phosphate dihydrate Salt Enzyme modified cheddar cheese Carrageenan* Potassium sorbate Color Buttermilk, 0.5% fat TOTAL *

% 1.0–2.0 52.0 6.0 1.2 0.7 0.85 0.5 0.55 0.15 qs to 100 100

Gelcarin GP 911 and Seakem GP 418, FMC Food Ingredients Division.

Modified from FMC Corp., 1994d. With permission of the FMC Corporation, Brussels, Belgium.

and lubricating the protein structure, Novagel™ improves both the melting and eating properties of low-fat cheeses (Bullens et al., 1994). Manufacturing typically involves dispersion in a premix tank followed by processing in a jacketed, processed cheese cooker. The dry ingredients are first dry blended and added to the buttermilk in the premix tank. The ingredients are incorporated by mixing using a planetary (or higher shear) mixer at approximately 1800 rpm for 4 to 8 minutes until smooth. In the jacketed cheese cooker, the cheese is shredded and the premix added while heating. The mixture is then heated to approximately 75°C under agitation and vacuum, and the product is packaged hot. 7A.6.5 FROZEN DESSERTS Colloidal microcrystalline cellulose prevents the growth of ice crystals in frozen foods during freeze-thaw cycles (FMC Corp., 1994c). The dispersed colloidal structure and large surface area allows for reabsorption of water and redispersion of components during the thaw cycle. Colloidal microcrystalline cellulose helps to prevent moisture migration and inhibits the irreversible aggregation of protein and other solids by maintaining a homogeneous state of the system. Dispersions of microcrystalline cellulose also contribute several other benefits such as opacity and a source of noncaloric fiber. Therefore, colloidal microcrystalline cellulose is used in standard, full-fat ice cream as well as in low-fat frozen desserts. An example of the application of Avicel® in a low-fat frozen formulation is shown in Table 7A.5.

7A.7 NUTRITIONAL AND TOXICOLOGICAL ASPECTS Powdered and colloidal grades of microcrystalline cellulose are nondigestible, zerocalorie food components that have no known toxicological risks. Microcrystalline cellulose has been evaluated by both the EC Scientific Committee for Food (SCF) and the Joint FAO/WHO Expert Committee for Food Additives (JECFA). Both committees have allocated the maximum Acceptable Daily Intake (ADI) of “not specified” (FMC Corp., 1993a).

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Table 7A.5 Use of Avicel® in a Low-Fat Frozen Dessert Containing 3% Fat Ingredients

%

Anhydrous butter fat or vegetable fat (30-32°C) Skim milk powder Sugar 42DE glucose syrup Mono and diglyceride emulsifier Stabilizer blend: Avicel® RC 581 Carrageenan* Guar gum Water TOTAL

3.0 12.2 12.0 4.0 0.2–0.5 0.25–0.5 0.05–0.2 0.1–0.2 qs 100

* Danagel IC 15, FMC Food Ingredients Division. Modified from FMC Corp., 1994c. With permission of the FMC Corporation, Philadelphia, PA.

7A.8 LEGISLATIVE AND LABELING STATUS In the U.S., microcrystalline cellulose has GRAS status and has been used safely in foods for over 30 years. In the European Union, in accordance with the EP/Council Directive 95/2/EC on Food Additives Other Than Colors and Sweeteners, microcrystalline cellulose (E460i) is listed in Appendix I and Appendix II (for use in cream) at quantum satis (QS). Sodium CMC, calcium alginate, and guar gum are also listed in Appendix I of this directive and are approved for use under numbers E466, E404, and E412, respectively.

REFERENCES Bullens, C., Krawczyk, G., and Geithmann, L., Reduced fat cheese products using carrageenan and microcrystalline cellulose, Food Technol., 48(1) 79, 1994. FMC A/S, Food Ingredients Division, Brussels, Belgium, Product Information Bulletins: 3010 Novagel™ RCN 10 and 3015 Novagel™ RCN 15, 1993b. FMC A/S, Food Ingredients Division, Brussels, Belgium, Application Note Microcrystalline CelluloseDM4-1: Low Fat Mayonnaise Dressings, 1993c. FMC A/S, Food Ingredients Division, Brussels, Belgium, Application Note MCC-CH2-1: <1% Fat Processed Cheese, 1994d. FMC Corporation, Food Ingredients Division, Philadelphia, PA, Avicel in Low/Non Fat Systems, Bulletin C-96, 1989. FMC Corporation, Food Ingredients Division, Philadelphia, PA, Customer Service Bulletin: Avicel® Cellulose Gel General Technology, 1993a. FMC Corporation, Food Ingredients Division, Philadelphia, PA, Customer Service Bulletin: Specifications and Product Information Avicel® AC 815 Cellulose Gel, 1994a. FMC Corporation, Food Ingredients Division, Philadelphia, PA, Customer Service Bulletin: Novagel™ Cellulose Gel Fat Replacer, 1994b. FMC Corporation, Food Ingredients Division, Philadelphia, PA, Application Bulletin: Avicel® Microcrystalline Cellulose in Frozen Desserts, 1994c. Imeson, A. P., Applications of Alginates, in Gums and Stabilisers for the Food Industry, Vol. 5, G.O. Phillips, D.J. Wedlock, and P.J. Williams, Eds., IRL Press, Oxford, U.K., 1989, 553. Mc Ginley, J. and Tuason, D.C., Fat-like Bulking Agent for Aqueous Foods Comprising Microcrystalline Cellulose and a Galactomannan Gum, U.S. Patent 5,192,569, 1993. Reilly, P. J. (1994), Personal communication. Tuason, D. (1994) Personal communication. Wyden, P. and Morrow, W., The Overweight Society, New York, 1965.

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Chapter

7B

Fiber-Based Fat Mimetics: Methylcellulose Gums Pablo de Mariscal and David A. Bell CONTENTS 7B.1 7B.2 7B.3 7B.4 7B.5 7B.6

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties Interactions with Other Food Ingredients Applications in Foods 7B.6.1 Fried Foods 7B.6.2 Liquid Foods 7B.6.3 Baked Products 7B.6.4 Frozen Dairy Products 7B.6.5 Low-Fat Whipped Toppings 7B.7 Nutritional and Toxicological Aspects 7B.8 Legislative and Labeling Status References

7B.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Methylcellulose (MC) was one of the earliest substitutes for plant gums in food applications. It was first produced in Germany in the 1920s and then in the U.S. in the 1930s by The Dow Chemical Company under the Methocel® registered trademark. Hydroxypropylmethyl-cellulose (HPMC) became commercially significant in the late 1940s. Used in a variety of food applications for more than 40 years, these polymers have demonstrated their ability to closely emulate important functional and textural characteristics

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of fats; they imitate the mouthfeel imparted by fats via film formation and rheological properties and they permit precise control of formulation viscosity so formulators can simulate fat-like texture in reduced-fat foods. Like fats, MC and HPMC help entrain air in foodstuffs to improve structure, stabilize air or carbon dioxide bubbles to reduce volume loss, and enhance moisture retention in a variety of products including sauces and dressings, restructured, frozen, and baked goods. In addition to The Dow Chemical Company, other manufacturers of these products for food use include Courtaulds Chemicals (Celacol®), Hercules Ltd. (Benecel®), Hoechst AG (Tylose®) and Shin-Etsu Chemical Co. (Metolose®).

7B.2 PRODUCTION PROCESS AND PATENT STATUS Cellulose, the raw material for the manufacture of MC and HPMC, is insoluble in most solvents due to its high level of intramolecular hydrogen bonding and degree of crystallinity. To make it soluble, its crystallinity and intramolecular hydrogen bonding need to be reduced. In the case of MC and HPMC products, this is accomplished by producing alkali cellulose by the addition of sodium hydroxide. This step swells the cellulose to facilitate substitution, particularly in regions of high crystallinity. Alkali cellulose is then allowed to react with methyl chloride to form MC. If the production of HPMC is desired, propylene oxide is added to the mixture. The relative amounts of methoxyl and hydroxypropoxyl substitution are controlled by the weight ratio and concentration of sodium hydroxide and the weight ratios of methyl chloride and propylene oxide per unit weight of cellulose. Any change in the amount of methyl chloride and in the reaction profile will affect the properties of the final product. The by-products formed in this process are removed by slurrying the crude product in water heated to above 90°C and then filtering. As MC and HPMC are insoluble in hot water, the unique thermal gelation properties of MC and HPMC are thus used to simplify the purification process. The resulting product, a moist porous cake, is dried using hot air, followed by grinding and packing. One of the advantages of MC and HPMC is that they can be produced within narrow specification limits. This is achieved by strict control over the manufacturing process, allowing for consistent production from batch to batch. This permits the manufacturer to formulate his products with a maximum of confidence, avoiding unpredictable behaviors of other less consistent gums in foodstuffs with an extreme pH (e.g., the acidic salad dressings) or that have to undergo stringent heat treatments (e.g., UHT and HTST processes).

7B.3 CHEMICAL COMPOSITION MC and HPMC are derived from cellulose, the most abundant polymer in nature. As a result of this immense supply, these gums are not subject to wide fluctuations in availability and product quality. The chemical structures of MC and HPMC are shown in Figure 7B.1. MC is described in the 78/663/EEC European Directive as “cellulose obtained directly from fibrous plant material and partially etherified with methyl groups” (European Council, 1978). HPMC is defined by the same Directive as “cellulose obtained directly from fibrous plant material and partially etherified with methyl groups and containing a small degree of hydroxypropyl substitution.” MC and HPMC are described in terms of their degree of substitution (DS) and molar substitution (MS). The DS can be defined as the amount of substituent groups on the anhydroglucose units of cellulose (three maximum) and the MS as the average number

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Figure 7B.1 Typical chemical structures of (a) methylcellulose and (b) hydroxypropylmethylcellulose. (Reprinted with permission of The Dow Chemical Company, Midland, MI.)

of molecules of substituent which have been substituted per anhydroglucose unit. The latter is used in the case of hydroxypropoxyl substitution because it is possible to form poly (hydroxypropoxyl) chains due to the additional hydroxyl group of the hydroxypropoxyl substituent. Although the control of the distribution of substituents of the individual anhydroglucose units is not believed to be of a great importance in commercial products used in food applications, the effects of changing the absolute level of substitution of methoxyl and hydropropoxyl substituents has a profound effect on the physicochemical properties of MC and HPMC (Grover, 1981). Therefore, water retention properties, sensitivity to electrolytes and other solutes, dissolution temperatures, gelation characteristics, and solubility in nonaqueous systems are all affected by variations in methoxyl and hydroxypropoxyl substitutions within the range permitted for food applications. For example, decreasing the methoxyl groups below a DS of 1.4 gives products whose solubility in water decreases. Concentrations of 2 to 8% sodium hydroxide are required for solubility as the level of substitution decreases. On the other hand, increasing the hydroxypropoxyl substitution above an MS of 2.0 improves the solubility in polar organic solvents. The range of methoxyl substitution permitted in MC under the above mentioned European Directive is 25.0 to 33.0%. This corresponds to a DS range of 1.49 to 2.00. For HPMC, the range is 3.0 to 12.0% of hydroxypropoxyl groups with 19.0 to 30.0% of methoxyl substitution (European Council, 1978). These ranges correspond to an MS range of 0.073 to 0.336 for hydroxypropoxyl groups and a DS range of 1.11 to 2.03 for methoxyl groups. Commercially available MC products, as produced by the various suppliers, have an average methoxyl degree of substitution ranging from 1.5 to 2.0. Hence, one half to two thirds of the available hydroxyl positions are substituted with methoxyl groups. In commercial HPMC products, the DS for methoxyl groups ranges from 0.9 to 1.9 and the MS for hydroxypropoxyl groups ranges from 0.073 to 0.336 (Table 7B.1).

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Table 7B.1 Typical Degree of Substitution and Weight Percent Substitution for the Methocel Range of Methylcellulose Gums Gum Type

Methoxyl degree of substitution

Methoxyl (%)

Hydroxy-propoxyl molar substitution

Hydroxy-propoxyl (%)

1.8 1.9 1.8 1.4

30 29 28 22

— 0.23 0.13 0.21

— 8.5 5.0 8.1

Methocel® A MC Methocel® E HPMC Methocel® F HPMC Methocel® K HPMC

Note: Determined using method ASTM D 2363-72 (The Dow Chemical Co., 1993). Reprinted with permission of The Dow Chemical Company, Midland, MI.

7B.4 PHYSICAL AND FUNCTIONAL PROPERTIES MC and HPMC may be dissolved in cold water to yield smooth, clear solutions with viscosities ranging from 3 to 100,000 mPa.s, as measured by ASTM D1347-72 and D2363-72 methods (The Dow Chemical Company, 1993) and illustrated in Table 7B.2. Solutions of MC and HPMC normally show pseudoplastic, nonthixotropic behaviors at temperatures below the gel point. Such behavior is a function of the molecular weight and the molecular weight distribution of the polymer. However, dilute solutions of lowviscosity products closely approach Newtonian flow. Table 7B.2 Range of Viscosities of 2% Aqueous Solutions of Methocel® Gums (Methylcellulose MC and Hydroxypropylmethylcellulose HPMC) at 20°C Methocel® Type MC A15LV premium MC A4M premium HPMC E15 food grade HPMC F50LV premium HPMC F4M premium HPMC K100LV premium HPMC K4M premium HPMC K100M premium

Nominal viscosity (Centipoise or millipascal seconds) 15 4,000 15 50 4,000 100 4,000 100,000

Note: Viscosity was determined by ASTM method D2363 (The Dow Chemical Company, 1993). Reprinted with permission of The Dow Chemical Company, Midland, MI.

Unlike other food gums, MC and HPMC products are available in a variety of molecular weights. This provides flexibility to the formulator in simulating the textures of fats and oils. At the low molecular weight end, these gums impart a mouthfeel that is similar to lower viscosity fats and oils while, at the upper end, MC and HPMC provide a texture and functionality resembling the more highly viscous plastic shortenings. Apparent viscosities as a function of gum concentration for selected MC and HPMC solutions are shown in Figure 7B.2. Another unique property of MC and HPMC products is that their solutions gel when heated to temperatures that are specific for each type. This is the opposite behavior to other gelling gums such as gelatin or alginates which melt at raised temperatures. This

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Figure 7B.2 Effect of concentration on viscosity for (a) low viscosity methylcellulose gums and (b) high viscosity methylcellulose gums in aqueous solutions at 20°C. (Reprinted with permission of The Dow Chemical Company, Midland, MI.)

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phenomenon has been explained by postulating that the water of hydration of the polymer chains in solution is gradually lost as the temperature of the solution increases (Henderson, 1987). When enough water of hydration is driven from the chains, these interact with one another and the solution gels (Figure 7B.3). This gelation process is reversible on cooling and can be affected by the presence of certain additives, e.g., salt, sugar, sorbitol, etc. (Henderson, 1988). The gels show thixotropic behavior until reversion upon cooling, whereupon pseudoplastic flow behavior occurs once again. The gel texture produced on heating aqueous solutions of these molecules varies with the type used. Normally, MC products yield firm gels, whereas gels obtained with HPMC products are softer. As methoxyl substitution is reduced and/or hydroxypropoxyl substitution increased, the gel texture softens. In low-fat products, this unique property contributes to simulate the texture otherwise provided by fats (De Mariscal, 1993).

Figure 7B.3 Effect of temperature on an aqueous solution of methylcellulose: thermal gelation of a 2% aqueous solution of METHOCEL® A 100 methylcellulose. Heating rate: 0.25°C/min. (Reprinted with permission of The Dow Chemical Company, MIdland, MI.)

Maximizing the functional and textural properties contributed by the fat that remains in a reduced-fat food is critical in simulating a full-fat product. To achieve this end, proper emulsification of the remaining fat droplets is essential. It is therefore beneficial to use stabilizers which not only modify the bulk aqueous phase of the food system but which also lower interfacial tension between the dissimilar phases of the food. MC and HPMC gums are surface active polymers due to their substitution and, as a result, they reduce the interfacial tension between the polar and nonpolar phases of emulsions (Sarkar, 1984). The hydrophilic hydroxyl groups along the cellulose backbone, along with the hydroxyls contributed by the hydroxypropoxyl substituents, provide affinity for water, while the lipophilic methoxyl groups substituted along the cellulose molecules impart

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affinity to nonpolar phases such as oil and air. MC and HPMC gums thus add stability to food emulsions by occupying sites at the interfaces between the oil or air droplets and the continuous aqueous phase. This interfacial activity means that high viscosity is not always necessary to increase emulsion stability, and the formulator’s flexibility to control the texture of the food is therefore increased by using MC or HPMC. A gum which is not surface active typically thickens a food product to stabilize the emulsion, but this may have detrimental effects on the texture of the product in some situations. The surface activities of MC, HPMC and other hydrocolloids are shown in Table 7B.3. For most MC and HPMC products, the surface tension of a solution decreases linearly as the sample is heated from 0°C until an apparent minimum surface tension is reached between 35° and 50°C (The Dow Chemical Company, 1990). This apparent minimum is specific for a given product, molecular weight, and concentration. Table 7B.3 Surface Activities of 1% Gum Solutions Gum type Water Xanthan gum Carboxymethylcellulose Hydroxyethylcellulose Sodium Alginate Propylene Glycol Alginate Methylcellulose Hydroxypropylmethylcellulose

Surface tension (Dynes/cm) 72 75 71 69 62 58 53–59 45–55

Reprinted with permission of The Dow Chemical Company, Midland, MI.

The reduced surface tension imparted by MC and HPMC makes these gums excellent film-formers. In fat reduction, film formation is important in creating a barrier to oil absorption in fried foods (Meyers and Conklin, 1988) and in creating a filmy mouthfeel that is similar to that of oil for low molecular weight gums and to that of shortenings for higher molecular weight gums (Bell, 1993). MC and HPMC are nonionic polymers. As a result, their solutions have a remarkable stability to changes in pH. In this respect, they differ from both anionic and cationic hydrocolloids which normally show dramatic changes in solubility and solution viscosity near their isoelectric point. Solutions of MC and HPMC are generally stable in the pH range of 3 to 11. Below pH 3, acid-catalyzed hydrolysis of the β –(1,4) bond becomes significant. Above pH 11, the polymeric chain is cleaved due to oxidative degradation (Greminger and Krumer, 1980). MC and HPMC gums are also very resistant to high temperatures. For example, MC and HPMC films can be molded or extruded at 120 to 190°C when blended with a suitable plasticizer such as sorbitol or glycerin.

7B.5 INTERACTIONS WITH OTHER FOOD INGREDIENTS MC and HPMC products are nonionic and are not precipitated as insoluble salts by multivalent metal ions. However, they can be salted out of solution when the concentration of electrolytes or other dissolved materials exceeds certain limits, as shown in Table 7B.4. This is caused by competition of the electrolytes for water and results in reduced hydration of these gums (The Dow Chemical Co., 1988). Water-insoluble materials,

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such as certain pigments or flavoring oils, do not adversely affect the gums. On the other hand, as MC and HPMC gums are not soluble in concentrated salt or sugar solutions, these media can be used as nonsolvent dispersing media. Subsequent dilution reduces the salt or sugar concentration to a level that allows the gum to dissolve and become fully functional. Table 7B.4 Grams of Additive Tolerated by 100 ml of 2% Solutions of Methocel® Gums at 20°C Methocel® Premium gum types Additive (g/100 ml)

A15

A4M

NaCl MgCl2 Na2CO3 Na3PO4 Sucrose

11 11 4 2.9 100

7 8 3 2.6 65

F50 17 35 5 3.9 120

F4M

K100

K4M

11 25 4 3.5 80

19 40 4 4.7 160

12 39 4 4.3 115

Reprinted with permission of The Dow Chemical Company, Midland MI.

Of particular practical interest is the synergistic effect encountered when low molecular weight MC is blended with modified starch. One of the problems found when starch alone is used to thicken a food product is that the viscosity of the latter drops as temperature increases. The result is often a liquid product with less than optimum appeal. By adding MC to modified starch, the viscosity increase that can be achieved when heat is applied is substantially greater than expected, the reason being that the thermal gelation property of MC counteracts the negative effect increased temperature has on the viscosity of a starch solution. The result is that solutions of MC/modified starch blends thicken as temperature increases (The Dow Chemical Company, 1988). This allows for reductions in the levels of starch to be made in some formulations. Tests done in model systems containing 0.5 to 1.0% MC and 2 to 5% modified corn starch show this interaction. A plot of the apparent viscosity as a function of heating for one modified starch and a low molecular weight methylcellulose is shown in Figure 7B.4. This interaction provides viscosity control over a wide range of temperatures. It introduces the capability of efficiently thickening a reduced-fat food as it is heated, which can be advantageous in sauces to impart cling to a substrate such as vegetables. The watery separation that occurs in some reduced-fat sauces when they are heated can be prevented using this interaction. In addition, a more uniform viscosity can be maintained over a broad temperature range in reduced-fat food products where neither an increase or decrease in viscosity is wanted as the product is heated. This is highly desirable not only in reduced-fat foods but in their fully-fatted counterparts as well. Applying the MC/starch interaction to reduced-fat food systems is a function of selecting appropriate concentrations for the MC and modified starch. As a result of the lower starch level, the caloric content of the food product may be reduced and there is less possibility of developing a starchy texture and taste. At the same time, the viscosity is better controlled and freeze/thaw stability is enhanced. As an additional benefit, there are fewer starchrelated processing problems such as burning starch on the walls of heat exchangers. MC and HPMC are also compatible with a substantial number of other water-soluble polymers. These include gum arabic, gum tragacanth, alginates, carrageenan, guar gum, xanthan gum, and many others.

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Figure 7B.4 Effect of temperature on viscosity of solutions containing a modified corn starch and a low viscosity methylcellulose. (Reprinted with permission of The Dow Chemical Company, Midland, MI.)

7B.6 APPLICATIONS IN FOODS 7B.6.1 FRIED FOODS The main benefit from using MC and HPMC in fried food products is the reduction in fat uptake achievable during the frying step (Meyers and Conklin, 1988; Bell and Steinke, 1991; Bell and Steinke, 1992; Pinthus, Weinberg, and Saguy, 1992; Bell, 1993; Pinthus, Weinberg, and Saguy, 1993). This contributes to a lower caloric value and improved cooking economy from reduced oil losses. At the same time, as more moisture is retained within the food matrix, the product is more juicy and the yield is improved. Frying batters can be improved using MC or HPMC. In addition to reducing the fat uptake, batters formulated with MC or HPMC are crunchier over a longer period of time and, thanks to the thermal gelation property, their adhesion to the substrate is enhanced. Batter pickup can also be optimized without increasing viscosity. These batters can be formulated with a higher level of water, so that yield is increased (The Dow Chemical Company, 1991). In fried sweet goods such as doughnuts, the moisture retaining properties of MC and HPMC impart a moist mouthfeel despite significant reductions in oil due to the film-forming properties of the gums. In cake and yeast-leavened doughnuts, oil reductions of 26 to 28% have been achieved without damaging appearance or mouthfeel (Bell and Steinke, 1991; Bell and Steinke, 1992). In reconstituted products, MC and HPMC function as binders and extrusion aids. They also help to keep the intended shape of extruded products and enhance the release properties in other forming processes. Such commercial matrix products as extruded shrimp, onion rings, and French fries benefit from the binding properties of MC and HPMC gums. Also, the freeze/thaw stability of frozen foods is improved due to the water-holding properties of these hydrocolloids. At the time of consumption, a better “bite” is achieved as a result of the gel structure created upon cooking. Another means of reducing fat in fried foods is to remove the frying step completely and utilize coatings to improve the flavor and appearance of the baked or broiled food. For meats, seafood, and poultry products, glazes may be applied which provide these properties, and the use of MC and HPMC in these glazes enhances their appearance and

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textural characteristics. Although other hydrocolloids can also provide thickening in cold glaze formulations, they do not contribute as readily to hot viscosity and hot cling as MC and HPMC. These gums have been shown to improve adhesion, gloss, texture, and viscosity in glazes as a function of film-forming, thermal gelation, and molecular weight properties (Conklin, 1993). 7B.6.2 LIQUID FOODS MC and HPMC are effective stabilizers in sauces and salad dressings. Moreover, they provide controlled pourability and mouthfeel characteristics through rheology adjustment. In reduced-calorie products, they are successfully used to obtain the texture of fully-fatted sauces. The interaction of low molecular weight MC with modified corn starches, as described previously, is an important property in controlling viscosity in sauces. Different combinations of MC or HPMC and other gums have been developed to prepare low-calorie sauces and dressings. Furthermore, zero-oil salad dressings have been successfully formulated using MC/xanthan gum blends (Table 7B.5). The processing method used consisted of heating the vinegar and water mixture to 50°C, dry-blending the food gums and sifting into the warm vinegar solution under gentle agitation, allowing the gums to hydrate, adding sugar and salt, and adding the previously dry-blended spices to the liquid. Table 7B.5 Use of a Methylcellulose (MC) Gum in a Mayonnnaise Substitute Formulation Containing 0% Oil Ingredients Water Vinegar Sugar Salt Minced onion Propylene glycol alginate MC Methocel® A4M Premium Garlic powder Xanthan gum Dried salad herbs Ground black pepper Cayenne pepper

% 45.60 45.60 4.90 2.00 0.50 0.40 0.30 0.30 0.20 0.10 0.05 0.05

Reprinted with permission of The Dow Chemical Company, Midland, MI.

7B.6.3 BAKED PRODUCTS Reduced-fat baked goods have benefited from the use of MC and HPMC in many ways. Just as fats contribute to increased volume and improved crumb structure, MC and HPMC compensate for fat removal by enhancing air entrainment, promoting uniform and fine cell size in the crumb structure (The Dow Chemical Company, 1993), and providing oven spring as these gums gel during baking (Bell, 1990). The thermal gelation property also provides a barrier to moisture loss during baking and cooling, which imparts a moist, shortening-like texture to the final product and can improve its shelf life as well. MC products improve structure and moist texture in reduced-fat cakes. In a study of gum effects in reduced-fat microwavable cakes, gum levels and moisture contents in the cake batters were varied using a central composite experimental design (Bell and Steinke, 1991). MC and HPMC increased cake height in yellow cake by about 7% and in chocolate ©1996 CRC Press LLC

cake by 12%, despite the stresses of microwave baking and reductions in fat of 65% for the yellow and 70% for the chocolate cake. Figure 7B.5 shows the surface response plot for gum concentration and batter moisture vs. cake height in microwave chocolate cake. The yellow and chocolate cakes containing low molecular weight HPMCs produced a favorable moist mouthfeel compared with the control, which was too dry in sensory panel evaluations. The chocolate cake formula that resulted from this study is shown in Table 7B.6. The cake was prepared using a Hobart-type mixer with a wire whip attachment for blending of the dry ingredients, adding shortening to the dry ingredients to obtain a fine crumb structure, adding water and vanilla and blending for 4 min, weighing 400 g of the cake mix into a previously prepared microwaveable pan, and baking for 5 min on a high setting.

Figure 7B.5 Chocolate cake height as a function of HPMC concentration and moisture. (Reprinted with permission of The Dow Chemical Company, Midland, MI.)

The surface activity of MC and HPMC also improves the whippability of reducedegg cake batters. The stabilization of the foam is further reinforced by the thermal gelation of these molecules during the baking stage. In addition, MC and HPMC aid in the production of low-gluten bread. There, they contribute to obtaining the body and texture normally associated with standard, full-gluten bread. Further benefits include increased tolerance to overmixing, longer holding times, and improved product yield. 7B.6.4 FROZEN DAIRY PRODUCTS In reduced-fat frozen desserts, it is critical that the sensory properties of the dairy fat be effectively emulated. Different combinations of hydrocolloids are often used for this purpose. A number of characteristics of HPMC make it particularly well-suited to frozen dessert and novelty applications. Its film-forming property, in combination with the thickening capability, simulates the coating property of fat in the mouth. Additionally, aqueous solutions of HPMC have lubricity, which further mimic the feel of fat.

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Table 7B.6 Use of a Hydroxypropylmethylcellulose (HPMC) Gum in a Reduced-Fat Microwave Chocolate Cake Formulation Ingredient Water Sugar Cake flour Dutched cocoa Vegetable shortening Nonfat dry milk Dry whole egg Vanilla Baking powder Lecithin Monoglycerides Salt HPMC Methocel F50LV Premium Baking soda Nutritional information

(%) 44.0 20.8 18.5 3.8 3.8 2.4 2.4 1.0 0.8 0.7 0.7 0.5 0.4 0.2 112 kcal/one-eighth of an 8-in. round cake.

Reprinted with permission of The Dow Chemical Company, Midland, MI.

The interfacial activity of HPMC is important in stabilizing fat droplets and air cells in reduced-fat frozen desserts. As an extender for the fat that remains, HPMC improves the emulsification stability of the fat globules in the continuous aqueous phase. Similarly, the surfactant properties entrain and stabilize air cells in the emulsion, contributing to the overrun of the dessert (the increase in product volume for a given weight resulting from air incorporation). Another applicable property of MC and HPMC is their cold water solubility. Both products are more readily soluble in cold water than in warm. As a result, at or near freezing temperature the hydrophilic tendency is very strong. The mobility of water that thaws during freeze/thaw cycling is consequently inhibited by MC and HPMC and ice crystal growth is reduced during refreezing after each thawing cycle. This reduces the formation of a sheath of ice around frozen novelties and improves the mouthfeel of these and other frozen desserts. This property is all the more important when the fat has been reduced in these products, since there is often more water present to compensate for the removed fat. An example of a fat-free frozen dessert formulation is given in Table 7B.7. The dessert was prepared by using part of the water in the formulation to make a 25% water solution of N-Oil, heating the N-Oil mixture to gelatinize, adding the N-Oil mixture and the previously blended dry ingredients to the remaining water, pasteurizing for 10 min at 75°C, homogenizing for 3 min, cooling to 5°C, ageing for at least 4 h and making the dessert using an ice cream machine adjusted to the overrun required. 7B.6.5 LOW-FAT WHIPPED TOPPINGS Similarly to frozen desserts, non-dairy whipped toppings are emulsions which include lipids and air as the discontinuous phases in a continuous aqueous matrix. As a group, whipped toppings are sensitive emulsions due to their low densities, and even small changes to a formulation can have significant effects on stability and appearance. Accordingly, the interfacial acitivity of MC and particularly HPMC are critical in providing air entrainment and stability to these food foams. The film-forming characteristic is particularly critical in reduced-oil toppings. Not only must the gum stabilize the remaining oil-and-air-in-water emulsion, but it is responsible for producing a fat-like textural character in the mouth as well.

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Table 7B.7 Use of a Hydroxypropylmethylcellulose (HPMC) Gum in a Fat-Free Frozen Dessert Formulation (Ice Cream Substitute) Ingredients Skimmed milk powder Sugar Glucose monohydrate N-Oil (National Starch & Chemical) Guar gum, carob gum, gelatin, carrageenan HMPMC ethocel E15 Food Grade Emulsifier Flavor Water

(%) 14.00 10.00 3.00 2.00 0.27 0.25 0.18 Q.S. 69.00

Reprinted with permission of The Dow Chemical Company, Midland, MI.

Since whipped toppings are low density and often low viscosity emulsions, the use of a low molecular weight stabilizer is appropriate. As a result, the property that can have the most beneficial effect on mouthfeel in the absence of high viscosity is filmformation, and HPMC is an excellent film-former. HPMC grades with a viscosity in the range of about 3 to about 100 mPa.s provide the best combination of emulsion stability, texture in the mouth, and visual appearance.

7B.7 NUTRITIONAL AND TOXICOLOGICAL ASPECTS MC and HPMC products are regarded as being soluble dietary fiber (Andon, 1987; Ink and Hurt, 1987). This means that they pass virtually unchanged into the colon where they are fermented to a variable extent (Passmore and Eastwood, 1986). Most methylcellulose gums pass out in the feces unaltered as they are highly resistant to enzymic degradation (Braun et al., 1974; Gorzinski et al., 1986). Commercial MC and HPMC products have been used by the food, pharmaceutical, and cosmetic industries for many years (Greminger and Krumer, 1980). Exposure to normal amounts presents no significant health hazard from either contact or inhalation. Therefore, they are considered to be physiologically inert. Dietary feeding studies in men, dogs, and rats have confirmed the inert nature of these polymers (Hodge et al. 1950; McCollister et al., 1973; Eastwood et al., 1990).

7B.8 LEGISLATIVE AND LABELING STATUS MC and HPMC are listed in the Food Chemicals Codex and the International Codex Alimentarius and included in the U.S. Pharmacopeia (USP XXII), European Pharmacopeia, British Pharmacopeia, and Japanese Pharmacopeia. In the U.S., MC is considered to be Generally Recognized As Safe (GRAS) under FDA regulation 21 CFR 182.1480. HPMC is approved for direct food use in nonstandardized foods as an emulsifier, film former, protective colloid, stabilizer, suspending agent, or thickener, in accordance with good manufacturing practice under FDA regulation 21 CFR 172.874. Food grade products are certified as kosher and pareve for year-round and Passover use by the Union of Orthodox Congregations of America. MC and HPMC are approved as food additives in Europe where their use is regulated by a set of Directives. Among the most important ones are Council Directives 78/663/EEC

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(purity criteria), 79/112/EEC (labeling), 89/107/EEC (framework directive on food additives), and their respective amendments. In December 1994, a proposal for a Council Directive on Food Additives Other Than Colors and Sweeteners was adopted and published on March 18, 1995 as Council Directive 95/2/EC. This new Directive establishes several criteria (Appendixes) relevant to MC and HPMC. The latter are listed in Appendix I meaning that these gums are allowed for use in all foodstuffs following the “quantum satis” principle (maximum levels limited only by good manufacturing practice), except for applications in certain foods specified in Appendix II, i.e., cocoa and chocolate products; fruit juices and nectars; jams, jellies, marmalade, and chestnut purée; and dehydrated and partially dehydrated milk. The Member States of the European Union have 18 months from the date of adoption (December 1994) to introduce this Directive into their national legislation at which point the Directive becomes fully enforceable. Until that happens, food manufacturers need to evaluate their particular case on a countryspecific basis. MC can be labeled either as “methylcellulose” or E-461. HPMC can be labeled either as “hydroxypropyl methylcellulose” or E-464.

REFERENCES Andon, S. A., Applications of soluble dietary fiber, Food Technol., 41(1), 74, 1987. Bell, D. A., Methylcellulose as a structure enhancer in bread baking, Cereal Foods World, 35(10), 1001, 1990. Bell, D. A., Formulating with methylcellulose food gums in fat-reduced foods. Paper presented in the Reduced-Calorie Food Product Development Short Course. AACC/IFT. Chicago, Illinois. March 3rd-5th, 1993. Bell, D. A. and Steinke, L. W., Effects on fat reduction and moisture retention in doughnuts by the addition of methylcellulose and hydroxypropylmethylcellulose. Poster Session, AACC Annual Meeting, Seattle, Washington, 1991. Bell, D. A. and Steinke, L. W., Evaluating structure and texture effects of methylcellulose gums in microwave-baked cakes, Cereal Foods World, 36(11), 941, 1991. Bell, D. A. and Steinke, L. W., Reduced fat uptake and increased moisture retention in yeast-leavened doughnuts with methylcellulose and hydroxypropylmethylcellulose. Poster Session, AACC Annual Meeting, Minneapolis, Minnesota, 1992. Braun, W. H., Ramsey J. C., and Gehring, P. J., The lack of significant absorption of methylcellulose 3300 cP from the gastro-intestinal tract following single and multipe oral doses to the rat. Food and Cosmet. Toxicol., 12, 373, 1974. Brenner, G. M., Sugarless Beverage. U.S. Patent 2,691,591, 1951. Conklin, J. R., Performance of food hydrocolloids in seafood glaze toppings. Poster Session, IFT National Meeting, Chicago, Illinois, 1993. De Mariscal, P., Methylcellulose food gums in reduced-calorie foods. Paper presented in the Course on Low-Calorie Food Product Development. AACC/IFT/CFDRA. Stratford-on-Avon. June 15th-17th, 1993. Eastwood, M. A., Brydon, W. G., and Anderson, D. M. W., The effects of dietary methylcellulose in man. Food Add. Contamin., 7(1), 9, 1990. European Council, European Council Directive 78/663/EEC, 1978. Gorzinski, S. J., Takahashi, I. T. and Hurst, G. H., The fate of ultra-low viscosity C-hydroxypropylmethylcellulose in rats following gavage administration. Drug and Chem. Toxicol. 9(2), 83, 1986. Greminger, G. K., Jr. and Krumer, K. L., Alkyl and hydroxyalkylalkylcellulose. In Handbook of Watersoluble Gums and Resins, R. L. Davidson, Ed., McGraw-Hill, New York, 1980. Grover, J. A., Methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) gums. In Food Hydrocolloids, 2nd ed., Vol. 3, M. Glicksman, Ed., CRC Press, Boca Raton, FL, 1981, 121. Henderson, A., Cellulose ethers- the role of thermal gelation, in Gums and Stabilizers for the Food Industry, Vol. 4, G. O. Phillips, D. J. Wedlock, and P. A. Williams, Eds., IRL Press, Oxford, 1987, 265.

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Henderson, A., Properties of MC and HPMC cellulose derivative gums. Food Technol. Int. Eur. 219, 1988. Hodge, H. C., Maynard, E. A., Wilt, W. G., Jr., Blanchet, H. J., Jr., and Hyatt, R. E., Chronic oral toxicity of a high gel point methylcellulose (Methocel HG) in rats and dogs. J. Phar. Exp. Ther., 99(1), 112, 1950. Ink, S. L. and Hurt, H. D., Nutritional implications of gums. Food Technol., 41(1), 77, 1987. Meyers, M. A. and Conklin, J. R., Method of Inhibiting Oil Absorption in Coated Fried Foods Using Hydrxypropylmethylcellulose, U.S. Patent 4,900,573, 1988. McCollister, S. B., Kociba, R. J., and McCollister, D. D., Dietary feeding studies of methylcellulose and hydroxypropylmethylcellulose in rats and dogs. Food Cosmet. Toxicol., 11, 943, 1973. Passmore, R. and Eastwood, M. A., Davidson and Passmore Human Nutrition and Dietetics, 8th. ed., Churchill Livingstone, Edinburgh, 1986. Pinthus, E. J., Weinberg P., and Saguy, I. S., Gel strength in restructured potato products affects oil uptake during deep-fat frying. J. Food Sci., 57 (6), 1359, 1992. Pinthus, E. J., Weinberg P., and Saguy, I. S., Criterion for oil uptake during deep-fat frying. J. Food Sci., 58 (1), 204, 1993. Sarkar, N., Structural interpretation of the interfactial properties of aqueous solutions of methylcellulose and hydroxypropylmethylcellulose. Polymer, 25, 481, 1984. The Dow Chemical Company, Starch Synergy with METHOCEL Premium Food Gums, Technical brochure, Midland, MI, 1988. The Dow Chemical Company, METHOCEL Cellulose Ethers. Technical handbook, Midland, MI, 1988. The Dow Chemical Company, A Food Technologist’s Guide to METHOCEL Premium Food Gums, Midland, MI, 1990. The Dow Chemical Company, METHOCEL Premium Food Gums in Fried Foods, Technical brochure, Midland, MI, 1991. The Dow Chemical Company, METHOCEL Food Gums. Product selection guide, Midland, MI, 1993. The Dow Chemical Company, Formulating Reduced-Fat Foods with METHOCEL Food Gums. Technical brochure, Midland, MI, 1993.

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Chapter

7C

Fiber-Based Fat Mimetics: Pectin Beinta Unni Nielsen CONTENTS 7C.1 7C.2 7C.3 7C.4 7C.5

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties Applications in Foods 7C.5.1 Spreads 7C.5.2 Mayonnaise 7C.5.3 Emulsified Meat Products 7C.6 Nutritional and Toxicological Aspects 7C.7 Legislative and Labeling Status References

7C.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Pectin is a purified carbohydrate product obtained by aqueous extraction under mildly acidic conditions of appropriate edible plant material — usually citrus fruits and apples. Traditionally, pectin is used as a gelling agent for jams and jellies. World production of commercial pectin is estimated at 20 to 25,000 metric tons per year (Vincent, 1986 cf. Pilnik and Voragen, 1992), and the major parts of all pectin production is consumed by the fruit processing industry. Other traditional applications are confectionery products, dairy products, fruit preparations, bakery fillings, and glazings. New applications within the food area are constantly developing, and fat replacement is one of the latest newcomers (Glicksman, 1991). In recent years, there have been a number of detailed reviews regarding pectin manufacture, structure, functionality, and applications (Nelson et al., 1977; Christensen,

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1986; Rolin and de Vries, 1990; May, 1990; Pilnik and Voragen, 1992; Rolin,1993). However, none of the earlier reviews has considered the use of pectin as a fat replacer, and this chapter is therefore mainly confined to the subject of fat replacement. SLENDID®, a registered trademark of Hercules Incorporated, was introduced in 1991. The SLENDID® concept covers a range of specialty pectins tailor-made for fat replacement (Pszczola, 1991). The production of SLENDID® takes place on the premises of Copenhagen Pectin A/S, a Division of Hercules Incorporated, in Denmark.

7C.2 PRODUCTION PROCESS AND PATENT STATUS Pectin is a natural constituent of almost all terrestrial plants. Together with cellulose, pectin is responsible for the structural properties of fruits and vegetables. The pectic substances are liberated from the raw material by extraction. Citrus peel and apple pomace, by-products of juice manufacture, are presently the only significant sources of commercial pectins. The peel or pomace may be blanched after juice extraction in order to inactivate the endogenously located pectin esterase, followed by drying. The production process of SLENDID® complies with traditional pectin manufacture, with the main steps being extraction from the plant material, purification of the liquid extract and isolation of the pectin. The product obtained with this process is a high ester (often called high methoxyl or HM) pectin. Alternatively, a controlled deesterification is applied either before the precipitation stage or between the precipitation and the draining stages leading to a low ester (often called low methoxyl or LM) pectin. Deesterification may be achieved with either acid or base. If ammonia is used for the deesterification, some of the methyl ester groups are substituted by amide groups, thus resulting in an amidated pectin. In order to achieve a consistent end product, pectin is standardized by blending different production batches together and adjusting the “strength” with sucrose or dextrose. The pectin yield from dried citrus peel is typically 20 to 30% whereas the yield from apple pomace is 10 to 15%. In 1994, Hercules Incorporated was granted a patent covering a fat simulating composition consisting of heat-stable carbohydrate gel particles, a food product normally containing fat/oil that has been improved by substituting all or a portion of the fat/oil by gel particles, and the process by which the gel particles are formed (Hoefler et al., 1994).

7C.3 CHEMICAL COMPOSITION SLENDID® is registered trademark for a range of proprietary specialty pectins derived from citrus peel and tailor-made for fat replacement. Presently the SLENDID® concept covers three products, SLENDID® 100, SLENDID® 110, and SLENDID® 200. A further line of SLENDID® products is expected to be introduced in the future. Commercial pectins are divided into LM-pectins and HM-pectins according to the degree of esterification (DE). DE is defined as the percentage of galacturonic acid units that are methyl esterified. Pectins with a DE below 50% are designated as LM-pectins, whereas pectins with DE above 50% are designated as HM-pectins. DE-values for commercial LMpectins typically range from 20 to 40%, and for HM-pectins from 55 to 75%. As mentioned earlier, some of the methyl ester groups may be substituted by ammonia, and in this case an amidated pectin occurs. The degree of amidation (DA) is defined as the percentage of amidated galacturonic acid units to the total galacturonic acid units. Typical DA-values range from 15 to 22%. Most commercial amidated pectins are of the LMpectin type, i.e., the so-called LMA-pectins. SLENDID® 100 and 110 are low ester pectins, while SLENDID® 200 is a high ester pectin.

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Pectin consists mainly of the partial methyl esters of polygalacturonic acid and their sodium, potassium, calcium, and ammonium salts. D-galacturonic acid units are diaxially linked by a-(1,4) -glucosidic bonds. The chain length varies from 200 to 1,000 galacturonic units, and a typical molecular weight (MW) as measured by relative viscosity methods, is 50 to 150,000 Daltons. Figure 7C.1 shows a HM-pectin (DE 60%) and a LMA- pectin (DE 40% and DA 20%). It has been shown that dried preparations of the pectin molecule form helices with three subunits per turn (Palmer and Hartzog, 1945). As to the molecular configuration in solution, it is believed that the HM-pectin helices pack in a parallel arrangement retaining the helical structure with 3 subunits per turn whereas the LM-pectin helices pack as corrugated sheets of antiparallel helices with 2 subunits per turn (Walkinshaw and Arnott, 1981).

Figure 7C.1 The chemical structure of high methoxyl and low methoxyl pectin.

LM-pectins require a controlled amount of calcium ions to form gels. Gelation may take place across a wide pH range (from 2.8 to 7.0). It has been suggested that calcium pectate gel formation is dependent on the stabilization of separate chain segments by OCa-O bridges (Walkinshaw and Arnott, 1981). Two pectin chains, free of ester groups, may arrange as corrugated sheets with an equivalent amount of calcium ions in between. Further, it has been suggested that a prerequisite for proper gel formation is the presence of approximately 15 consecutive nonesterified galacturonic acid residues in either molecule (Morris, 1990). A popular model for calcium-pectate gel formation is the so called “egg-box” model. This model was originally proposed for describing the gelation of calcium alginate (Morris et al., 1978). According to the “egg box” model, the helices form with only two subunits per turn. This model therefore contradicts the assumption of three subunits per turn. However, the model may still be valid if it is assumed that the conformation of pectin during the dissolution process changes from three to two subunits per turn. Nevertheless, it is unlikely that pectins are extensively cross-linked as indicated by the “egg-box” mechanism. This was confirmed by recent investigations (Renard et al., 1993; Axelos et al., 1991). Amidated LM-pectins require less calcium for gelling than nonamidated LM-pectins. Amidated types usually gel in a fruit system without an exogenous source of calcium, i.e., with the calcium originating from fruit and water. By contrast, nonamidated types require addition of calcium for proper gelling.

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HM-pectins require acidic conditions (pH 2.0 to 3.5) and the presence of soluble solids measured as sucrose by refractometry of at least 55% for gelation. It has been suggested that the gelation mechanism relies on intermolecular hydrogen bonds and hydrophobic interactions between methyl ester groups (Walkinshaw and Arnott, 1981). Parallel polygalacturonan chains are packed in a hexagonal lattice with columns of methyl groups arranged in the interstices. It has been verified that the galacturonan backbone is occasionally interrupted by the insertion of a-(1,2)-linked L-rhamnose residues. The rhamnose insertions provide “kinks” in the molecular chain which restrict the formation of potential junction zones. Powell and co-workers (1982) have suggested an even distribution of rhamnose insertions with a length of polygalacturonate sequences between rhamnose insertions of approximately 20 to 30 residues. By contrast, de Vries and co-workers (1982) have suggested a model which consists of a long homogalacturonan chain intercepted by a few relatively short “hairy” regions containing all rhamnose insertions and neutral sugar side chains, i.e., galactose, glucose, arabinose, xylose. The amount of neutral sugars is approximately 5 to 10% of the amount of galacturonic acid.

7C.4 PHYSICAL AND FUNCTIONAL PROPERTIES All SLENDID® types are available as dry powders with virtually unlimited shelf-life. SLENDID® 100 and 110 are LM-pectins whereas SLENDID® 200 is an HM-pectin. The basic functionality of types 100 and 110 is as gelling agents, and it is therefore necessary that LM gelling conditions are used, i.e., calcium ions are required for gelling. With SLENDID® 200, however, the functionality relies on a swelling process, i.e., as a water binder. SLENDID® 100 and 110 are sodium-salts in contrast to SLENDID® 200 which is a calcium-salt. Since type 200 functions as a water binder and not as a gelling agent, the HM-conditions for gelling need not be fulfilled. The SLENDID® concept offers a range of properties including: label-friendliness since it is a pectin; stability to heat, pH, shear, and salt; neutral taste (making it easy to flavor); fat-like dissipation; virtually no calories; and relatively low usage levels, i.e., 0.2 to 1.5%. The main difference between types 100 and 110 is in their viscosity, the 110 type being a higher viscosity version. Therefore, SLENDID® 110 is typically used at a lower level compared to SLENDID® 100. For historical reasons, it should be mentioned that the original SLENDID® is similar to SLENDID® 100. For applications where severe heat treatment is necessary such as with soups and sauces, the use of SLENDID®100 and 110 is recommended since the heat stability of these types is superior to that of SLENDID® 200. SLENDID® 100 and 110 are very calcium reactive LM-pectins. In order to mimic fat, types 100 and 110 are dissolved in deionized or soft water and gelled with calcium ions. Different soluble calcium donors may be applied such as calcium chloride, calcium citrate, or skimmed milk powder, the selection depending on the pH of the finished food product. Optimum performance is achieved with the addition of 30 mg calcium ions per gram SLENDID® 100/110. A broken gel is formed which is subsequently homogenized in a colloid mill or a homogenizer, resulting in a so-called wet preparation with a smooth creamy consistency and a fat-like homogeneous appearance. For most applications, a median particle size of 25 to 50 µm is recommended in order to mimic the physical and sensory characteristics of emulsified fat, and a standard dairy homogenization, i.e., 150/50 bar is generally adequate. Figure 7C.2 shows the reduction in particle size with a 3.72% SLENDID® 100 wet preparation vs. degree of shearing, i.e., homogenization pressure. The particle size was measured by means of laser diffraction using a Malvern Mastersizer E, reading the volume distribution.

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Figure 7C.2 Particle size of SLENDID® 100 wet preparation at 3.72% vs. pressure after a single stage homogenization.

For most applications, SLENDID® 100 and 110 can simply be added as a dry powder for gelling and shearing in situ. Premixing of the SLENDID® powder with other dry ingredients in the food recipe such as sugar or starch improves dispersibility. However, with some food applications such as meat and fish products, a separate sheared water gel containing more than 95% water is prepared. When separately making up the wet preparation, usage levels in the range 1.5 to 4.0% are recommended, and the final usage level in finished food products is in the range of 0.4 to 1.5%. The viscosity h [Pa s] vs. shear rate g· [s –1] of a SLENDID® 100 wet preparation at 3.72% before and after homogenization is shown in Figure 7C.3 as a log-log plot. Data were generated using a Bohlin VOR Rheometer. Both preparations were pseudoplastic, i.e., exhibiting reduced viscosity with increasing shear rates. With low shear rates, i.e., 5 to 10 s–1, the nonhomogenized sample had a viscosity 4 to 5 times higher (20 to 50 Pa s) than the homogenized sample (5 to 10 Pa s). However, with higher shear rates, the difference was reduced, the viscosity of the nonhomogenized sample being only twice that of the homogenized counterpart. SLENDID® 110 showed similar trends but the viscosity was approximately 50% higher. SLENDID® 200, a calcium salt of a HM-pectin, is an instant type of product that may be added directly to water. The pectin does not dissolve, but rather swells instantly into big soft particles, with an average particle size greater than 250 µm. Due to the very soft nature of the swollen particles, the original particle size is significantly reduced during food processing. The viscosity of a range of SLENDID® 200 concentrations is depicted in Figure 7C.4. The figure illustrates that at very low concentrations, SLENDID® 200 exhibits near-Newtonian behavior whereas at high concentrations, pseudoplastic behavior becomes predominant. The recommended usage level of SLENDID® 200 is 0.3 to 0.8%.

7C.5 APPLICATIONS IN FOODS SLENDID® may be used in a wide range of food applications such as spreads, mayonnaises and salad dressings, processed meats, ice cream, processed cheeses, soups and sauces, desserts, and bakery products, in which fat may be partly or fully replaced. This section deals with the application of SLENDID® in the first three product categories only. ©1996 CRC Press LLC

Figure 7C.3 Viscosity vs. shear rate of SLENDID® 100 wet preparation at 3.72% before and after a two-stage homogenization (150/50 bar).

Figure 7C.4 Viscosity vs. shear rate for a range of SLENDID® 200 concentrations.

7C.5.1 SPREADS Traditional oil-continuous products for spreading contain 80% fat. When lowering the fat content, it becomes increasingly difficult to maintain the original water-in-oil emulsion. Therefore, aqueous phase stabilizers are often added to the water phase in order to maintain a continuous oil phase (Wilbey, 1988). The most commonly used stabilizers in low fat spreads are milk proteins, gelatin, modified starches, carrageenans, and alginates (Moran, 1991). Other hydrocolloids that may be used include pectin, xanthan, and locust bean gum. In addition to the thickening and stabilizing effect, the addition of milk solids may have a just-noticeable destabilizing effect on the water-in-oil emulsion leading to easier phase inversion in the oral cavity.

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Using SLENDID® 100 it is possible to prepare oil-continuous spreads containing 20% fat (Nielsen, 1992). In the original recipe with SLENDID® 100, it was a prerequisite that the water phase was homogenized. However, with the introduction of SLENDID® 200, the homogenization step is omitted. Type 200 swells instantly in tap water and is ready for use. As shown in Table 7C.1, the oil phase consists of a liquid vegetable oil fraction and a hydrogenated vegetable oil fraction in the ratio 2:1 and a blend of two emulsifiers. For high-fat spreads, it is usually sufficient to use distilled monoglycerides. However, with low-fat versions, a more stable emulsion is achieved by the addition of polyglycerol polyricinoleate (PGPR). Aroma, color, vitamins, and preservatives are added optionally. The spread is prepared according to standard processing methods using a Perfector or Kombinator-type unit. Table 7C.1 Use of SLENDID® 200 in a Low-Fat Spread Containing 20% Fat Order of addition A B

C

Ingredients Oil phase Hydrogenated palm oil Soy oil Distilled monoglycerides (emulsifier) Polyglycerol polyricinoleate (emulsifier) Water phase Tap water SLENDID® 200 Salt Total

Content % 6.4 12.8 0.7 0.1 78.2 0.8 1.0 100.0

From Nielsen, B.U. and Hansen, K.M., Annu. Trans. Nordic Rheol. Soc., Vol. 2, Copenhagen, 1994, 44. With permission.

Different rheological models have been used for characterizing spreads, e.g., the Casson Model and the Herschel-Bulkley Model. It has been suggested that conventional high-fat spreads follow the Casson equation whereas low-fat versions exhibit HerschelBulkley flow behavior (Stern and Cmolik, 1976). Good correlation has been reported between empirical rheological data and sensory analysis (deMan et al., 1979). It has been suggested that the yield stress has a range where an optimum spreadability is achieved. Too high a value results in a hard, difficult-to-spread product, whereas too low a value results in a soft and destabilized product (Rohm and Raaber, 1991; Diris, 1992). By applying oscillatory measurements, it is possible to determine the critical shear stress which may be thought of as being similar to the static yield stress. Stress sweeps for two spreads prepared according to Table 7C.1 with PGPR and without PGPR added are shown in Figure 7C.5. From the stress sweep, the critical shear stress, scrit, is determined as the shear stress s where G′ = 0.9G′ lin applies, G′ lin being the linear value of the storage modulus, G′ before the onset of deformation. A controlled stress (CS) rheometer of the type Haake RheoStress RS100 was used for the rheological characterization. For a more detailed discussion of the general principles of rheological analysis, the reader is referred to Chapter 9. G′ lin was almost identical for the two spreads, i.e., 40 to 50 Pa, indicating that the firmness of the spreads was comparable. However, scrit of a PGPR-containing spread was significantly higher (128 Pa) than for its corresponding counterpart containing only distilled monoglycerides (52 Pa). Sensory analysis confirmed that a PGPR-containing spread was more acceptable from a spreading point of view,

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Figure 7C.5 G′ vs. stress for a 20% fat spread stabilized with SLENDID® 200 with (0.1%) and without polyglycerol polyricinoleate (PGPR) added. (From Nielsen, B.U. and Hansen, K.M., Annu. Trans. Nordic Rheol. Soc., Vol. 2, Copenhagen, 1994, 44. With permission.)

while the spread with no PGPR was unacceptably slippery and understabilized. Additional information on the use of different emulsifiers in low-fat spreads can be found in Chapter 10. Nondestructive rheological measurements have been used to characterize the meltability of low-fat spreads. By applying a temperature ramp, the melting process of the spreads during consumption was simulated. Figure 7C.6 shows the storage modulus G´ and the phase angle d as a function of temperature. It was observed that G′ declined drastically at 35 to 40°C indicating that a phase inversion had taken place at the temperature of the oral cavity. A perceived melting temperature may be defined as the temperature where the storage modulus G′ and the loss modulus G≤ exhibit identical values, i.e., with the phase angle, d, being 45°. Using this definition, a melting temperature of 39°C for a SLENDID® 200 containing spread was obtained. A similar phase inversion temperature was found with a commercial 80% fat containing spread (Nielsen and Hansen, 1994). Borwankar and co-workers (1992) used a similar approach for characterizing a range of low-fat spreads and concluded that the perceived meltability of such products correlated with the sensation of flow, i.e., the rheology, and not simply with the melting of fat. However, the phase angle was not monitored and the melting temperature was defined arbitrarily as corresponding to a certain value of the complex viscoelastic modulus G*. The water droplet size in a traditional 80% fat spread is typically below 10 µm. Normally, with lower fat versions, the droplet size increases and the product is therefore more prone to bacterial contamination. However, microscopic evaluation of a 20% fat spread stabilized with SLENDID® 200 confirmed that the water droplet size was reduced significantly during spread processing, i.e., from a particle size above 250 µm to a particle size of approximately 25 µm. 7C.5.2 MAYONNAISE Mayonnaise is an oil-in-water emulsion. Traditionally, the oil content is 80%, and the main ingredients in descending order are: vegetable oil, water, acetic acid, and egg yolk. The egg yolk provides emulsifying properties and gives the pale yellow color (Holcomb

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Figure 7C.6 G’ and d vs. temperature for a 20% fat spread with SLENDID® 200. Phase inversion temperature was 39°C. (From Nielsen, B.U. and Hansen, K.M., Annu. Trans. Nordic Rheol. Soc., Vol. 2, Copenhagen, 1994, 44. With permission.)

et al., 1990). For preservation purposes, sodium benzoate or potassium sorbate may be added. Salt and mustard are added optionally. Whereas low-calorie mayonnaise (typically with 30 to 40% oil) always contains external stabilizers, the full fat (80%) version may also contain stabilizers in order to increase shelf life stability (Arnell, 1990). Typical stabilizers are modified starch, alginates, carboxymethyl cellulose (CMC), locust bean gum, guar gum, and xanthan. The latter three categories are discussed in more detail in Chapter 9. Using SLENDID® 100, it is possible to reduce the oil content of a mayonnaise from 80% to 3%. A mayonnaise recipe containing 20% oil is given in Table 7C.2. When reducing the oil content to 3%, it is recommended that additional external stabilizers, e.g., xanthan and guar gum, are used. The mayonnaise is prepared according to conventional mayonnaise processing methods. Briefly, the dry ingredients are added to part of the oil. The water phase is placed in a colloid mill of the Fryma, Koruma, or DixieCharlotte type and the dry mix is added during mixing. The remaining oil is then added and when the product becomes homogeneous, the egg yolk and acid are added. The rheological properties of mayonnaise may be described as Bingham plastic or pseudoplastic with a yield stress (Figoni and Shoemaker, 1983). The Casson equation which is typically used for characterization of melted chocolate has been found suitable for estimation of the yield stress of mayonnaise (Lahtinen, 1986; Paredes et al., 1988). In the literature, yield stress values in the range 40 to 50 Pa have been reported (Lahtinen, 1986). Figure 7C.7 depicts a log-log plot of shear stress vs. shear rate for two SLENDID® 100-containing mayonnaises (20 and 3% oil). It is evident that the two mayonnaises exhibited similar, pseudoplastic flow behavior. Applying the Casson equation to the data gives yield stress values of 44 Pa and 59 Pa for the mayonnaises containing 20 and 3% oil, respectively. Commercial mayonnaises with 80 and 40% oil gave similar yield stress values, i.e., 61 Pa and 72 Pa, respectively. The oil droplet size in an 80% fat mayonnaise is typically 2 to 5 µm. If a mayonnaise is not properly stabilized, the oil droplets coalesce, and the viscosity is reduced (Sherman, 1983). Accordingly, the stability of a mayonnaise emulsion may be reflected by the mean diameter of the oil droplet in the dispersed phase. A study conducted with increasing

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Table 7C.2 Use of SLENDID® 100 in a Low-Fat Mayonnaise Containing 20% Oil Order of addition A

B C D

Ingredients SLENDID® 100 Sugar Modified starch Sodium caseinate Oil Water, color, flavor, preservative Egg yolks Calcium chloride Salt Vinegar Mustard Total

Content % 1.20 4.00 3.00 2.00 20.00 57.20 4.00 0.10 1.00 7.00 0.50 100.00

Figure 7C.7 Shear stress vs. shear rate for mayonnaises stabilized with SLENDID® 100 and containing 20% or 3% oil.

addition of SLENDID® 200 to a 20% oil mayonnaise has shown that the average median particle size of the oil droplets was inversely related to the SLENDID® 200 concentration, as shown in Figure 7C.8. A control with no SLENDID® added had an average oil droplet size of approximately 40 µm whereas the addition of 0.5% SLENDID ® resulted in reduction in the oil droplet size down to approximately 15 µm. 7C.5.3 EMULSIFIED MEAT PRODUCTS Typical emulsified meat products are sausages and pâtés or meat spreads. Conventional emulsified meat products contain relatively high amounts of fat, i.e., 25 to 35%. Two options exist for reducing the fat content in an emulsified meat product: either introduction of an increased amount of lean meat in the recipe or substitution of the fat with

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Figure 7C.8 Oil particle size vs. SLENDID® 200 use levels for a mayonnaise containing 20% oil.

water. Whereas the first option gives a very firm product, the latter option ensures that the original succulence is maintained. The choice, however, depends on national preferences. Using SLENDID® 110, it is possible to reduce the fat content in a frankfurter from 25 to 35% to 3 to 5%, as shown in Table 7C.3. When using SLENDID® 110 for emulsified meat products, it is necessary to prepare a separate water gel by homogenization or similar process. Since the pH in a frankfurter is approximately 5.5 to 6.0, calcium citrate is the preferred calcium donor salt. Furthermore, carrageenan is added in order to give optimal texture and good sliceability. A wet preparation of 2.0%, resulting in a final SLENDID® 110 usage level of approximately 0.9%, was found to give optimal texture characteristics. The matrix is processed according to normal procedures whereby meat and texturized soy protein are added to a bowl chopper followed by phosphate, nitrite salts, and half of the wet preparation. This is followed by carrageenan, soy isolate, and the remaining wet preparation, and finally the starch and ascorbate. The product is cut until the desired consistency is achieved and is then filled, dried, smoked, and cooked. Table 7C.3 Use of SLENDID® 110 in a Low-Fat Frankfurter Formulation Ingredients Shank meat Water/ice Sodium tripolyphosphate Nitrite salt (sodium chloride with 0.6% sodium nitrite) Texturized soy protein Carrageenan (GENUGEL type MB-73) SLENDID® 110 (2% wet preparation) Soy protein Sodium ascorbate Potato starch Total

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Content % 40.00 6.00 0.50 1.80 1.50 0.50 46.65 1.00 0.05 2.00 100.00

7C.6 NUTRITIONAL AND TOXICOLOGICAL ASPECTS Pectin is characterized as a water-soluble dietary fiber (Roehrig, 1988). A characteristic feature of dietary fiber is that it is resistant to hydrolysis by human digestive enzymes. However, some fibers are partially degraded by intestinal bacteria in the colon. Thus, soluble fibers are almost completely metabolized to short-chain fatty acids, methane, carbon dioxide, hydrogen, and water. Cummings and co-workers (1979) have suggested that pectin is completely metabolized in the human gut, whereas Müller and Kirchgessner (1985) reported an apparent digestibility value of 79% and a metabolizability of 71%. Net energy values were measured as 9 kJ/g digestible pectin corresponding to 7 kJ/g pectin. The net energy value of pectin is thus only 64% of the energy value of starch digested in the small intestine. In most countries, food legislative authorities recognize pectin as a valuable and harmless food additive. If regulated, permitted use levels are generally in accordance with “good manufacturing practice”. Pectin was evaluated and cleared toxicologically by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1981 (WHO, 1981). It was verified that there are no toxicological differences between pectins and amidated pectins and a group ADI (Acceptable Daily Intake) “not specified” was established for pectins and amidated pectins.

7C.7 LEGISLATIVE AND LABELING STATUS The identity and purity of SLENDID® conforms to the internationally accepted specifications for the identity and purity of pectins (FAO, 1992; Food Chemicals Codex (FCC), 1981; EEC, 1978). At the time of writing, the FCC does not include calcium salts of pectin; however, this regulation is expected to be amended shortly to include the calcium salt. In the U.S., pectin is affirmed GRAS (Generally Recognized as Safe) as defined in Code of Federal Regulations 184.1588 (U.S. FDA, 1986). The European Union has adopted pectin as a food additive under the designation E440.

REFERENCES Arnell, M., Majonnäs och dressing. Livsmedelsteknik 32(10), 36, 1990. Axelos, M.A.V., Garnier, C., and Thibault, J.-F., An example of ionic complexation in biopolymers: The pectin-calcium system. AIP Conf. Proc. 226, 569, 1991. Borwankar, R.P., Frye, L.A., Blaurock, A.E., and Sasevich, F.J., Rheological characterization of melting of margarines and tablespreads. J. Food Eng. 16, 55, 1992. Christensen, S.H., Pectins, in Food Hydrocolloids, Vol. III, Glicksman, M., Ed., CRC Press, Boca Raton, FL, 1986, 205. Cummings, J.H., Southgate, D.A.T., Branch, W.J., Wiggins, H.S.: Houston, H., Jenkins, D.J.A., Jivraj, T., and Hill, M.J., The digestion of pectin in the human gut and its effect on calcium absorption and large bowel function. Br. J. Nutr. 41, 477, 1979. deMan, J.M., Dobbs, J.E., and Sherman, P., Spreadability of butter and margarine, in Food Texture and Rheology, Sherman, P., Ed., Academic Press, London, 1979, 43. de Vries, J.A., Rombouts, F.M., Voragen, A.G.J., and Pilnik, W., Enzymic degradation of apple pectins. Carbohydr. Polym. 2, 25, 1982. Diris, J., Rhéologie et corps gras. Application à l’étude de margarines et de pâtes à tartiner. Rev. Fr. Corps Gras, 39(9/10), 253, 1992. EEC, Council Directive 78/663. Off. J. EEC 14 08 78 (plus Updates) 1978. FAO, Food and Nutrition Paper, 52, Addendum 1, Rome, 1992, 87. Figoni, P.I. and Shoemaker, C.F., Characterization of time dependent flow properties of mayonnaise under steady shear. J. Texture Stud., 14(5), 431, 1983.

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Food Chemicals Codex, FCC III Monographs, 3rd ed., National Academy Press, Washington D.C. (including supplements), 1981, 215. Glicksman, M., Hydrocolloids and the search for the “Oily Grail.” Food Technol. 45(10), 94, 1991. Hoefler, A.C., Sleap, J.A., and Trudso, J.E., Assignee Hercules Inc., U.S., Fat Substitute. U.S. Patent 5,324,531, 1994. Holcomb, D.N., Ford, L.D., and Martin. R.W., Jr., Dressings and sauces, in Food Emulsions, 2nd ed., Larsson, K. and Friberg, S.E., Eds., Marcel Dekker Inc., New York, 1990, 327. Lahtinen, S., Physical effects of salt mixtures in mayonnaise. J. Food Qual., 9(1), 1, 1986. May, C.D., Industrial pectins: Sources, production and applications. Carbohydr. Polym. 12, 79, 1990. Moran, D., Developments in yellow fat spreads. Chem. Ind., 11, 379, 1991. Morris, E.R., Industrial hydrocolloids, in The Structure, Dynamics and Equilibrium Properties of Colloidal Systems, Bloor, D.M. and Wyn-Jones, E., Eds., Kluwer Academic Publishers, Netherlands, 1990, 449. Morris, E.R., Rees, D.A., Thom, D., and Boyd, J., Chiroptical and stoichiometric evidence of a specific, primary dimerisation process in alginate gelation. Carbohydr. Res. 66, 145, 1978. Müller, H.L. and Kirchgessner, M., Energetische Verwertung von Pektin bei Sauen. Z. Tierphysiol. Tierernährung Futtermittelkunde, 54, 14, 1985. Nelson, D.B., Smit, C.J.B., and Wiles, R., Commercially important pectic substances, in Food Colloids, Graham, H.D., Ed., Avi, Westport, CT, 1977, 418. Nielsen, B.U., Low Fat Spreads — SLENDIDTM gives splendid results. FIE Conference Proceedings, Düsseldorf, Nov. 25–27, 1992, 202. Nielsen, B.U. and Hansen, K.M., Rheological characterization of low fat spreads. Annu. Trans. Nordic Rheol. Soc., Vol. 2, Copenhagen, June 1–3, 1994, 44. Palmer, K.J. and Hartzog, M.B., An X-ray diffraction investigation of sodium pectate. J. Am. Chem. Soc. 67, 2122, 1945. Paredes, M.D., Rao, M.A., and Bourne, M.C., Rheological characterization of salad dressings. 1. Steady shear, thixotropy and effect of temperature. J. Texture Stud. 19(2), 247, 1988. Pilnik, W. and Voragen, A.G.J., Gelling agents (pectins) from plants for the food industry. Adv. Plant Cell Biochem. Biotechnol. 1, 219, 1992. Powell, D.A., Morris, E.R., Gidley, M.J., and Rees, D.A., Conformations and interactions of pectins. II. Influence of residue sequence on chain association in calcium pectate gels. J. Mol. Biol. 155, 517, 1982. Pszczola, D.E., Pectin’s functionality finds use in fat-replacer market. Food Technol. 45(12), 116, 1991. Renard, C.M.G.C., Thibault, J.-F., Liners, F., and Van Cutsem, P., Immunological probing of pectins isolated in situ. Acta Bot. Neerl. 42(2), 199, 1993. Roehrig, K.L., The physiological effects of dietary fiber — A Review. Food Hydrocoll. 2 (1), 1, 1988. Rohm, H. and Raaber, S., Hedonic spreadability optima of selected edible fats, J. Sensory Stud. 6, 81, 1991. Rolin, C., Pectin, in Industrial Gums, 3rd ed., Whistler, R.L. and BeMiller, J.N., Eds., Academic Press, 1993, 257. Rolin, C. and de Vries, J.A., Pectin, in Food Gels, Harrris, P., Ed., Elsevier Applied Science, London and New York, 1990, 401. Sherman, P., Rheological properties of emulsions, in Encyclopedia of Emulsion Technology, Becher, P., Ed., Marcel Dekker, New York, 1983, 405. Stern, P. and Cmolik, J., Study of rheological properties of margarine. J. Am. Oil Chem. Soc. 53, 644, 1976. U.S. FDA Federal Register, paragraph 184.1588, 437, 1986. Vincent, A., Food texture additives. Proc. Inst. Food Sci. Technol. 3, 107, 1986. Walkinshaw, M.D and Arnott, S., Conformations and interactions of pectins. I. Models for junction zones in pectinic acid and calcium pectate gels. J. Mol. Biol. 153, 1075, 1981. WHO, Evaluation of certain Food Additives. Tech. Rep. Ser., 669, Geneva 1981. Wilbey, R.A., Technical problems in the development of low-calorie dairy products, in Low-Calorie Products (Birch, G.G. and Lindley, M.G., Eds.), Elsevier Applied Science Publishers, Ltd., Cambridge 1988, 31.

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Chapter

8

Microparticulated Proteins as Fat Mimetics Norman S. Singer CONTENTS 8.1 8.2 8.3 8.4

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties 8.4.1 Stability of Microparticulated Protein Particles (MP3) 8.4.2 Sensory Properties of MP3 8.4.3 The Rheology of Creaminess 8.4.4 Microparticulate Concentration 8.4.5 Microstructure of MP3 8.5 Interactions with Other Food Ingredients 8.6 Applications in Foods 8.7 Nutritional and Toxicological Aspects 8.8 Legislative and Labeling Status References

8.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Microparticulated protein is a natural ingredient which owes its efficacy in replacing fat in foods to the novel physical form in which it has been caused to gel. This gel is in the form of microparticles, each about one thousandth of a millimeter in diameter. Each microparticle is composed of many millions of intact protein molecules (Tang et al., 1989; Dudley et al., 1989). The use of protein microparticles has made it possible to retain traditional sensory qualities while substantially reducing the fat content of foods (Singer and Moser, 1993).

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What we are all addressing in this text is the need to resolve one of the powerful approach-avoidance conflicts which now confronts the western world: enjoyment or health. Mankind seems to be unique in its treatment of ingestion as a personal pleasure which when shared, becomes a basis for social communion. We are the only animal that fusses over the preparation of its food. With the exception of such curiosities as the delicate precision with which a lobster eats a crab, animals simply ingest their food. For mankind, it is perhaps the second greatest source of pleasure, and so it has over the millenia become an art form. At a time when so many other pleasures have so suddenly become forbidden, we cannot expect the consuming public to easily surrender this one. The now-familiar message from health care associations urging us to eat a more healthful, low-fat diet seems to be understood by consumers. Yet, they (we) do not seem ready to abandon traditional enjoyments. One need only look at the large numbers of low-fat products on the shelves of supermarkets to appreciate just how strong the consuming public’s hope is that they can eat more healthfully without having to resort to a more primitive diet. However, this hope works against a powerful counter-current expectation that food which is “good for you” probably tastes bad (Drewnowski, 1990a; Rose, 1991). It must be observed that much of the low-fat food offered to consumers on those shelves can only reinforce this negative expectation. Further, the recent experiments which have shown that people can learn to accept a more spartan diet (Mattes, 1993) did not measure the effect of this regimen upon the panelists’ estimation of their quality of life. We must not ignore the fact that globally, food nourishes the soul as well as the body. The task which confronts the food industry then is nothing less than learning how to produce, in a low-fat language, the kind of sensory poetry upon which food companies were founded. This language includes the alphabet of new ingredients which have been made available to address the very real health concerns of consumers. The capacity of protein microparticles to confer sensory impressions of fatty emulsions upon fat-free foods was a serendipitous discovery (Singer et al., 1988), which proved to be the bellwether for the recent food industry campaign against high-fat contents. Simplesse®, the product which arose from that discovery, is made by the NutraSweet Company. It was the first fat replacer to be affirmed by the U.S. Food and Drug Administration as GRAS (Generally Recognized as Safe) (FDA, 1990).

8.2 PRODUCTION PROCESS AND PATENT STATUS Proteins have been caused to gel in this novel physical form by what amounts to a simple rearrangement of traditional food processing operations. As solutions of thermally coagulable proteins are heated, the constituent molecules denature (unfold), and then proceed to aggregate. The process of molecular aggregation begins with dimers, and with continued heating can proceed to the point where all of the molecules in the protein pool are incorporated. However, we found that this natural tendency to aggregate can be halted in the micrometer-range by the imposition of shearing forces of adequate intensity during the heating. The resulting process can best be described as the simultaneous (rather than sequential) performance of the unit-processes of homogenization and pasteurization (Singer, 1992). Patents are in place which cover the microparticulate state and the microparticulate product (Singer et al., 1988), the products arising from the use of the microparticulated proteins (Singer et al., 1989, 1991, 1992a, 1992b, and 1992c), as well as the process of microparticulation (Singer, Speckman, and Weber, 1989).

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8.3 CHEMICAL COMPOSITION The most popular form of microparticulated protein starts with whey protein concentrate. As a consequence of dedicated development efforts, this product is now made from whey protein concentrate (WPC) without adjuvants (Fang and Snook, 1991). Thus, since it is compositionally the same as WPC, differing only in its physical form, this ingredient falls under the regulatory standard of identity for WPC and can be so labeled. Either 35 or 50% protein WPCs can be used as the starting material.

8.4 PHYSICAL AND FUNCTIONAL PROPERTIES Microparticulated protein (MPP) functions as a surrogate dispersed phase, replacing the fat droplets which conventionally provide dispersed phase functions. The nature of these “dispersed phase functions” will be familiar to those who have worked with such conventional dispersed phase systems as creams, mayonnaise, chocolate, frankfurters, pasta, etc. However, they have not yet been generalized, and thus are not conveniently described or referenced. 8.4.1 STABILITY OF MICROPARTICULATED PROTEIN PARTICLES (MP3) In order for the dispersed phase functions to confer their beneficial effects on food systems, the microparticulated protein particles (MP3) which provide them must be stable to all of the stresses which can be anticipated in the processing, handling, storage, and use of the finished product. At the same time, it seems to this author that a key requirement for such an ingredient to be considered natural is that it be digested and used by the body in a manner essentially identical to the unstructured material from which it was made. Evidence that MP3 can satisfy these requirements can be found in the literature. The stability of MP3 toward pH, within the range of pH 3 to 7, has been reported (Clark, 1994). As shown in Figure 8.1, MP3 derived from whey protein have zero zeta-potential at about pH 4.6, that is, the net surface charge of the particles is zero at that pH. Yet there is no tendency for the particles to aggregate even at zero net charge. The voluminosity or the interaction of the particles with water actually reaches a minimum at the pH of zero charge repulsion (Figure 8.1). The decreased voluminosity results from the decreased charge repulsion within the particles which allows the hydrophobic interactions to draw the MP3 subunits together and thus cause each particle to contract slightly. Stability toward heat in the range 10 to 95°C has also been reported (Clark et al., 1992). That the identity of the protein is not changed by the process of microparticulation was reported by Singer and co-workers (1990) while the conservation of protein quality was reported by Dudley and co-workers (1989), and by Erdman (1990). Therefore, it can be concluded that controlling the size of the particle into which proteins aggregate is a physical, rather than a chemical change. 8.4.2 SENSORY PROPERTIES OF MP3 The numerous functions of fat in food have been extensively reviewed in recent years. Papers by Lucca and Tepper (1994), and Best (1992) are examples of this body of literature. As these reviews make amply clear, fat provides a variety of functions in traditional foods. Of these, we are most interested in creaminess. While this is an outstanding characteristic of many very pleasing foods, it is not yet well understood. In early investigations of the nature of creaminess in soups, “creaminess” was identified as “a property which has defied rheological description” (Wood, 1974). What was clear even then was that smoothness is an essential component of creaminess. In this paper,

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Figure 8.1 Stability of whey protein microparticles to changes in pH. (From Clark, D. R., Bringe, N., Bishay, I., and Desai, N., IDF Seminar, Protein and Fat Globule Modification, Munich, August 1992, The NutraSweet Co., Deerfield, IL. With permission.)

we therefore examine what is known about both smoothness and creaminess, before we examine how these effects can be achieved by the use of MP3. It has been reported that people sense smoothness by rubbing food between the tongue and the palate (Cussler et al., 1979). Wood (1974) had cogently observed that… “powderiness gave a strong anti-creaminess impression.” In this observation, he agrees with Prentice’s effort to define terms for the creamy impression (Prentice, 1973). Both of these investigators point to a combination of the impressions of “viscosity and sliminess” as being important in conveying the sense of creaminess. In later work, Cussler and colleagues (1979) and later, Kokini (1987) proposed that creaminess is a function of both smoothness and thickness. This would seem to place them in substantial disagreement with the earlier work. However, they define smoothness as “inversely proportional to the friction force between the tongue and the roof of the mouth” (Cussler et al., 1979). The author of this chapter finds that this definition conveys more the sense of lubricity (or sliminess) and thus supports the earlier proposals of Wood (1974) and Prentice (1973). This apparent difference in definitive focus may have arisen from the fact that Kokini’s sensory panelists were reported to have been given the term “smoothness” and asked to scale the intensities of the various solutions with which they were presented (Kokini, 1987). We have followed the lead of Stevens who demonstrated that smoothness is approximately the inverse of roughness (Stevens and Harris, 1962). These researchers (working with blind manual assessments of bonded abrasives) found that perceived roughness increased as a power function of particle size, and that the perception of smoothness was approximately the inverse of roughness. While this earlier work provided valuable direction, the author of this chapter found two surprising discontinuities in the oral sensing of particulates (Singer et al., 1988). The first of these relates to smoothness and the second to the sense of substantialness. These two concepts are discussed in more detail below. We found that particles larger than about 3 µm in aqueous dispersion are sensed as powdery, chalky, gritty, etc. (with increasing particle size). In this range, the relationship between particle size and roughness seems to follow the pattern described by Stevens. On the other hand, particles smaller than about 2 µm are simply not sensed as particles. Instead, the tongue senses the overall characteristics of the fluid MP3 dispersion as smooth

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and rich, which is more typically associated with oil-in-water (o/w) emulsions such as full-fat mayonnaise. In the realm of food microparticulates, therefore, we have defined “smoothness” as the absence of particulate roughness (Singer et al., 1988). For evidence of this upper discontinuity (sensory threshold), we can compare the scanning electron micrographs shown in Figures 8.2 a and b. Both specimens consist of acid-cooked whey protein. The upper specimen represents a product which has been sold for over 30 years as a nutritional supplement and which has been described as having a “gritty” mouthfeel. The lower specimen is Simplesse® which is characteristically smooth. The small size and round shape of Simplesse® make possible the creaminess which is so characteristic of this class of ingredient (Singer, 1992).

Figure 8.2 Scanning electron micrographs (SEM) of acid-cooked whey protein demonstrating the upper threshold of the “unique interval.” The upper SEM shows a product which has been sold for over 30 years as a nutritional substitute, and which has been described as “gritty.” The lower SEM is of Simplesse® which is characteristically smooth. The only differences between the two are size and shape. (From Singer, N. S., ADPI/CDR Proc. of the Dairy Products Technical Conference, Chicago, April 25–26, 85, 1990. With permission.)

We found that while suspended particles larger than about 0.5 µm convey to the taster an impression which we have called “substantialness,” dispersions of particles which are smaller than about 0.1 µm impart none of this sense of substance. This proposed term may be synonymous with the terms “body” and “richness.” We believe that consumers refer to the absence of substantialness as “wateriness” (Singer, 1992). Experiential evidence of this lower threshold can be found in the sensory responses to skim milk. ©1996 CRC Press LLC

Figure 8.3 Transmission electron micrograph (TEM) of skim milk showing the uniformity of native casein micelles whose size is below the optimal for conveying a sense of “substantialness.” (From M. Kalab, Ottawa, Canada. With permission.)

The micelles of casein are predominantly smaller than 0.2 µm, as shown in Figure 8.3. This size is below that which is required for optimal creaminess giving rise to the watery taste of skim milk, as compared with the rich taste of regular milk (Singer, 1992). Further experiential evidence is unfortunately readily available in the marketplace in those lowfat foods in which the dispersed phase functions have been overlooked. Microparticles lying in the narrow range between the two sensory thresholds described above convey the impression of substantialness without conveying the feeling of particulateness. This combination of sensory properties, termed the “unique interval,” makes it possible for the net perception to be interpreted as creaminess (Singer, 1992). These relationships are graphically represented in Figure 8.4. In exploring the MP3 phenomenon, we tasted and microscopically examined dispersions of many foods and other materials, as discussed in more detail later in this chapter. In the course of these explorations, we observed that even when ultrafine particles fell within the unique interval but were needle-shaped, rod-shaped, or were characterized by angular surface topology, they would not flow smoothly in the crucial tongue/palate test, but tended to pack into “log jams,” whereupon they were sensed as much larger masses. Even though transient, this impression was unpleasant, and distinctly foreign to creamy foods, and so the illusion of creaminess could not be established. We therefore generalized from these experiences that, to be effective in fat substitution, MP3 could not depart from the spheroidal (Civille, 1990; Singer, 1992). 8.4.3 THE RHEOLOGY OF CREAMINESS Some pioneering efforts in the rheological characterization of creaminess have been reported recently (Bishay and Clark, 1994; Clark et al., 1992). In this work, illustrated in Figure 8.5, it has been demonstrated that dispersions of MP3 paralleled the rheological character of a classical emulsion (whipping cream) very closely. All of the products tested had been prepared according to manufacturers’ instructions and were presented for testing at their recommended usage levels. Where the manufacturer had recommended a range of concentrations, the median value was used. The shapes of the flow curves in Figure 8.5 are more revealing of rheological character than the magnitudes of the curves.

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Figure 8.4 Graphical representation of the “unique interval,” the fortuitous span between the two oral sensory discontinuities which define the relationship between microparticulate size and sensory impression. (From Singer, N. S. and Dunn, J. M., J. Am. Coll. Nutr., 9, 388, 1990a. With permission.)

The shape of the flow curve for whipping cream, used as a standard for creamy rheology, showed that it flowed smoothly even at the lowest shear rates and that it thinned with increasing shear rate. The Simplesse® sample behaved in a similar way. By contrast, a variety of gum and starch products which are being promoted as fat replacers (including the colloidal microcrystalline cellulose Avicel® CL611 [see Chapter 7A]; the potato maltodextrin Paselli SA2 [see Chapter 6B]; and the oat maltodextrin/β -glucan Oatrim 3) deviated from this behavior. The shapes of the flow curves of all the fat replacers other than Simplesse® suggested that they may be very useful in controlling water, but that they could not simulate creaminess (Figure 8.5). 8.4.4 MICROPARTICULATE CONCENTRATION It should be obvious to anyone skilled in the art (and who has read this far) that one or two MP3/cc are not enough to generate a creamy impression any better than would be a few globules of fat/cc. While the actual concentration required in any application needs to be determined on a case-by-case basis, the number of microparticles required to create the effect is typically in the order of 107 to 109/cc. The very large numbers of microparticles contained in Simplesse® allow relatively small amounts of protein to replace relatively larger amounts of fat (Singer, 1992). To summarize the effects of the dispersed phase, we have seen that the size, shape, uniformity, and concentration, as well as the nonaggregated nature of these particles are characteristics which, working together, enable these particles to replace fat as the dispersed phase of o/w emulsion products (Singer and Dunn, 1990b). While other

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Figure 8.5 Rheological comparison of the shapes of the flow curves of whipping cream, Simplesse®, and four commercial fat replacers or fat-sparing ingredients. (From Clark, D. R., Bringe, N., Bishay, I., and Desai, N., IDF Seminar, Protein and Fat Globule Modification, Munich, August 1992, The Nutrasweet Co., Deerfield, IL. With permission).

properties of MP3 have also been identified which contribute to their effectiveness in replacing fat in foods, they cannot be disclosed at this time. 8.4.5 MICROSTRUCTURE OF MP3 The microstructure of MP3 has been intensively examined by means of light microscopy, electron microscopy (both scanning and transmission EM), immunogold staining (Singer and Dunn, 1990a) and more recently by means of atomic force microscopy, as exemplified in Figure 8.6 (Bringe and Clark, 1993). Of all the microscopic techniques, the latter entails the least risk of artifactual distortion. The findings of all of these techniques agree that the MP3 in Simplesse® are spheroidal aggregations of protein molecules which are uniform in size and which are themselves not further aggregated. While the techniques of scanning and transmission electron microscopy have been used to examine the ultrastructure of food products for more than three decades, the first formal examination of the microparticulate state in a range of foods was reported in 1990 by Kalab. Kalab’s investigation revealed that a considerable variety of fine particles can be found in conventional foods (Kalab, 1990). The fine structure of meat, for example, is composed of microfibrils of myosin. Mammalian milks contain an abundance of casein in micellar form (Figure 8.3). In leguminous seeds, the storage protein is commonly found in the form of protein bodies. The form of these fine particles may change when the foods which contain them are processed prior to consumption. For example, when meat is processed to form a hot dog (frankfurter), the fibrils aggregate into a globular form, embedded in a reticulum characteristic of gels. The textural variety of dairy foods can be seen to arise at least in part from the extent and nature of aggregation of the casein micelles. In yogurt, the micelles of casein can be seen to be connected in a tenuous network which correlates well with the tender gel which characterizes this product (Figure 8.7), while in cream cheese, which is much firmer, the casein micelle network is more substantial. In addition, the micelles in cream cheese can be seen to be concentrated

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Figure 8.6 Atomic force micrographs of MP3 (Simplesse®) showing their spheroidal form. (From The Nutrasweet Co., Deerfield, IL. With permission.)

in the membranes around the abundant fat globules. In ripened cheeses like cheddar, the casein micelles have completely lost their identity, their constituent protein molecules having aggregated into a plastic continuum (Figure 8.8). From this we can see that aggregations of fine particles underlie many familiar food textures. In contrast to these fine particulate structures, MP3 are uniformly spheroidal, of a strikingly narrow size range (about 1 µm in diameter) and entirely unconnected, as shown in Figure 8.9 (Dunn, 1989). We can conclude from Kalab’s report (1990) that while microparticulated proteins occur naturally in foods, they are not found in the necessary size, shape, and abundance to function as fat mimetics. Another study of the structure and function of protein microparticulates further supported the earlier empirical finding that the size and shape of the particles were essential in providing fat-like mouthfeel (Civille, 1990).

8.5 INTERACTIONS WITH OTHER FOOD INGREDIENTS Ten years of experience with applications of MP3 have revealed that this ingredient is extraordinarily compatible with a wide variety of food ingredients. The most important interaction appears to be the synergy observed between MP3 and the other ingredients which are required to complete the illusion. Once an effective concentration of a suitable MP3 has been incorporated into a low-fat food, other ingredients are usually required to complement or complete the illusion of high-fat content in order to achieve the highest consumer satisfaction. These ingredients are familiar to formulators who are accustomed to the use of the full palette of food materials normally used to adjust viscosity, set, handling properties, mouthfeel, and flavor (Singer, 1992).

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Figure 8.7 Scanning electron micrograph of yogurt showing the extensive reticular matrix which connects essentailly all of the casein micelles and which is responsible for the characteristic texture of the unstirred product. (From M. Kalab, Ottawa, Canada. With permission.)

Figure 8.8 Transmission electron micrograph of a low-fat cheddar cheese prepared with Simplesse® and aged for 6 weeks showing the amorphous continuum into which the casein micelles have formed by the cheesemaking process. The intact and separate identity of MP3 which serve as a surrogate dispersed phase replacing butterfat globules is also shown. (From The Nutrasweet Co. Deerfield, IL. With permission.)

One of the most daunting challenges in fat replacement is replication of the flavors of the traditional high-fat products. We have become accustomed to not only the specific flavors of certain fats in our foods, but to the shape of the flavors arising from fatty foods. Take away the fat, and the flavor changes. The new flavor profile, being different, is frequently disappointing. Although the flavor industry has responded well to this problem, the flavor of many low-fat foods remains disappointing (Drewnowski, 1990b). ©1996 CRC Press LLC

Figure 8.9 Light micrograph showing MP3 (Simplesse®) at a concentration of 1.5% in water (before deposition) and demonstrating size, shape, uniformity, and the individual or unconnected nature of the microparticles. (From Singer, N. S. and Dunn, J. M., J. Am. Coll. Nutr., 9, 388, 1990a. With permission.)

A tool which should not be overlooked in the quest for a realistic flavor profile in low-fat foods is the way in which the chemistry of a fat substitute itself causes it to interact with flavoring materials. Two studies out of a series conducted by Gary Reineccius at the University of Minnesota (Schirle-Keller et al., 1992; Schirle-Keller et al., 1994 [see also Chapter 4, Section 4.6.4 for additional details on this work]) and described by Clark (1994) in the context of further work (Reineccius, 1994) can serve as a Rosetta stone. The data presented in Figure 8.10 is a compilation of the above studies as presented by Clark (1994) and shows interactions between pairs of model systems: a model flavor system and a model fat/fat replacer system. The model flavor system consisted of a 0.5% solution of members of a homologous series of aldehyde aroma compounds in propylene glycol. The model fat/fat replacer system consisted of water in which lipid (corn oil) or a fat replacer and emulsifier (Tween 60 at 0.5%) were thoroughly distributed. A control was prepared in which water replaced the fat or the fat replacer. The fat replacers studied included Simplesse® 100 at 5%, Simplesse® 300 at 10% (to achieve the same protein levels as with Simplesse® 100), Slendid® at 2% (level of addition constrained by very high viscosity), Stellar™ at 5%, Oatrim at 5% and Paselli SA2 at 5%. The model flavor system was presented to the model fat/fat replacer system at a level of 2% and mixed by hand. Aliquots of this mixture were then transferred to headspace vials and stored at 4°C for subsequent testing. It can be seen from Figure 8.10 that as the aldehyde chain

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Figure 8.10 Interaction of a series of flavors (aliphatic aldehydes) with a group of commercial fat replacers. A corn oil emulsion was used as reference. (From data compiled by Clark (1994), The Nutrasweet Co., Deerfield, IL. With permission.)

length increased, the two MP3 ingredients (Simplesse® 100 and Simplesse® 300) behaved more like the corn oil emulsion than the carbohydrate-based fat replacers. From this, we would expect the flavor arising from the use of Simplesse® to be more fat-like than that obtained from the use of the carbohydrate-based fat replacers examined, assuming that no other remedial steps are taken.

8.6 APPLICATIONS IN FOODS The first commercial use of MP3 in the U.S. was in the fat-free “ice cream” Simple Pleasures. A comparison of the structure of this product with a full-fat ice cream is shown in Figure 8.11. This product demonstrated that it is feasible to produce foods which are both fat-free and great tasting if the dispersed phase functions of fat globules are effectively replaced. Many other MP3-based products have been brought to the market, including low-fat cheese spreads (Kaukauna), low-fat cheesecakes (Eli’s), fat-free frozen novelties (Eskimo Pie), low-fat natural cheeses, including Cheddar (Cabot), Colby, muenster, and Monterey Jack (Kroeger and White Clover), and ricotta and mozzarella (Falbo). The development of the low-fat mozzarella made possible the production of low-fat pizza (Home Run Inn). Internationally, MP3 has been used to produce a fat-free butter spread in Ireland and a line of fat-free frozen desserts in Finland (Singer, 1992). Recently, it has been reported that MP3 has been effectively applied in the production of low-fat baked goods (Corliss, 1992).

8.7 NUTRITIONAL AND TOXICOLOGICAL ASPECTS Rigorous scientific examination has demonstrated that the highly nutritive quality of the proteins is unchanged during Simplesse® production. The protein particles have been

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Figure 8.11 Transmission electron micrographs of full-fat ice cream (left) and a fat-free ice cream made with Simplesse® (MP3, right), demonstrating how MP3 can be used as a surrogate dispersed phase to replace the fat globules (F). (From Singer, N. S. and Dunn, J. M., J. Am. Coll. Nutr., 9, 388, 1990a. With permission.)

subjected to extensive analyses by independent research investigators in an evaluation more typical of the pharmaceutical industry than the food industry. The organization of the protein molecules in the particles was examined by transmission electron microscopy and immunogold staining as described earlier (Singer and Dunn, 1990b). The identity of the constituent proteins was examined by gel electrophoresis (Tang et al., 1989), amino acid assays (Dudley et al., 1989), protein efficiency ratios (Dudley et al., 1989), and in vitro allergenicity tests (Sampson, 1990). All of these examinations confirmed that the amino acid sequence and three-dimensional structure of the proteins were unchanged by the microparticulation process. The only difference was in the physical way in which the protein molecules aggregated (Singer and Moser, 1993). Replacement of unwanted fat in the diet with protein is an excellent nutritional exchange. When fats are metabolized, the energy derived from 1 g is approximately 9 kcal. Proteins and carbohydrates are digested by different reactions and “contain” less energy; 1 g of either protein or carbohydrate is approximately equivalent to 4 kcal (Stryer, 1988). Hence, the exchange of protein or carbohydrate for fat is an excellent way to reduce both caloric intake, and the percentage of calories derived from fat. In those products where MP3 replaces animal fat, a significant reduction in saturated fat and cholesterol content is also achieved. It should be remembered that people who are allergic to milk proteins can be expected to be allergic to MP3 made from those proteins. Studies of the antibody responses of patients allergic to cow’s milk proteins indicate that allergic individuals had no greater antibody response to proteins in the Simplesse® samples than to the proteins from cow’s milk (Sampson, 1990).

8.8 LEGISLATIVE AND LABELING STATUS In 1990, the FDA affirmed MP3 (Simplesse®) prepared from egg white and/or skim milk to be GRAS for use in frozen desserts (FDA, 1990). A second form of Simplesse® ©1996 CRC Press LLC

prepared from whey protein concentrate with no adjuvants was approved by the FDA in August 1991 for use in a wide range of food applications. Labeling for the latter, more popular version of Simplesse® is easily accomplished since it conforms to the U.S. Standard of Identity for whey protein concentrate and can be so labeled. The legislative and labeling position of Simplesse® is similar in Europe and the reader is referred to Chapter 5 for a more detailed discussion of some of the specific European issues involved in its approval for use in foods.

REFERENCES Best, D. A., Fat substitutes: Finding method in the madness, Prep. Foods, 162, 21, 1992. Bishray, I.E. and Clark, D.R., The rheological characterization of microparticulated fat substitutes, Paper No. 55 of the Division of Agricultural and Food Chemistry of the 207th National Meeting of the American Chemical Society, San Diego, March 13–17, 1994. Bringe, N. A., Dry microparticulated protein product, International Patent Appl. WO 93/07761, 1993. Bringe, N. A. and Clark, D. R., Simplesse® formation and properties, Science for the Food Industry of the 21st Century, Yalpani, M., Ed., ATL Press, Mount Prospect, IL, 1993, chap. 5. Civille, G. V., The sensory properties of products made with microparticulated protein, J. Am. Coll. Nutr., 9, 427, 1990. Clark, D. R.Fat replacers and fat substitutes, IFT; Ingredient Technology Short Course, Chicago, May, 1994. Clark, D. R., Conversion of whey protein to microparticulated fat substitute, Food Science and Nutrition Colloquium, Cornell University, New York, May, 1993. Clark, D. R., Bringe, N., Bishay, I., and Desai, N., Rheological characterization of microparticulated fat substitutes and their contribution to creaminess, IDF Seminar, Protein and Fat Globule Modification, Munich, August 1992. Corliss, G. A., Protein-based fat substitutes in bakery foods, AIB Tech. Bull., 14, 10, 1992. Cussler, E. L., Kokini, J., Weinheimer, R., and Moskowitz, H., Food texture in the mouth, Food Technol., 33, 89, 1979. Drewnowski, A., The new fat replacements, a strategy for reducing fat consumption., Post Grad. Med., 87, 111, 1990a. Drewnowski, A., Dietary fats: perceptions and preferences, J. Am. Coll. Nutr., 9, 431, 1990b. Dudley, R., et al., Microparticulation of protein in Simplesse® does not alter protein efficiency ratio, FASEB, March, 1989. Dunn, J. M., Electron microscopic characterization of microparticulated protein (Simplesse®), FASEB, March, 1989. Erdman, J. W., The quality of microparticulated protein, J. Am. Coll. Nutr., 9, 398, 1990. Fang, C. S. and Snook, R., Proteinaceous fat substitute, International Patent Application, WO 91/17665, November, 1991. FDA, Microparticulated protein product 21 CFR 184.1498, 1990, U.S. Government Printing Office, Washington, D.C. Kalab, M., Microparticulate protein in foods., J. Am. Coll. Nutr., 9, 374, 1990. Kokini, J. L., The physical basis of liquid food texture, J. Food Eng., 6, 51, 1987. Kokini, J. L., Kadane, J. B., and Cussler, E. L., Liquid texture perceived in the mouth, J. Texture Stud., 8, 195, 1977. Kretchmer, N., Summary: microparticulated protein, J. Am. Coll. Nutr., 9, 371, 1990. Lucca, P. A. and Tepper, B. J., Fat replacers and the functionality of fat in foods, Trends Food Sci. Technol., 5, 12, 1994. Mattes, R., Fat preference and adherence to a reduced-fat diet, Am. J. Clin. Nutr., 57, 373, 1993. Morse, R. E., Singer, N. S., Fat replacers, Kirk-Othmer Encycloped. Chem. Technol., 10, 239, 1994. Prentice, J. H., Terminology of the texture of cream, J. Texture Stud., 4 154, 1973. Reineccius, G.A., Personal communication, 1994. Rose, F., If it feels good, it must be bad, Fortune, p. 91, Oct., 1991. Sampson, H. A. and Cooke, S. K., Potential allergenicity-antigenicity of microparticulated egg and cow’s milk proteins, J. Am. Coll. Nutr., 9, 410, 1990.

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Schirle-Keller, J.P., Chang, H.H., and Reineccius, G.A., Interaction of flavor compounds with microparticulated proteins, J. Food Sci., 57, 1448, 1992. Schirle-Keller, J.P., Reineccius, G.A., and Hatchwell, L.C., Flavor interactions with fat replacers: Effect of oil level, J. Food Sci. 59, 813, 1994. Sherman, P., Hydrocolloid solutions and gels. Sensory evaluations and their dependance on rheology, Prog. Food Nutr. Sci., 6, 269, 1982. Singer, N. S., Simplesse®: All natural fat substitute and the dairy industry, ADPI/CDR Proc. of the Dairy Products Technical Conference, Chicago, April 25–26, 1990, 85. Singer, N. S., Simplesse®, Advanced Food Ingredients Symposium, Rutgers University, New Brunswick, March, 1992. Singer, N.S. and Dunn, J.M., Protein microparticulation: The principle and the process, presented at a conference on Nutritional and Functional Properties of Microparticulated Protein, Berkeley, November 27, 1989. Singer, N. S. and Dunn, J. M., Protein microparticulation: The principle and the process, J. Am. Coll. Nutr., 9, 388, 1990a. Singer, N. S. and Dunn, J. M., Microparticulated protein: A structural analog of the water-in-oil emulsion, Presented as Paper #46, IFT, Anaheim, June, 1990b. Singer, N. S., Dunn, J. M., Tang, P., and Chang, H. H., Conservation of protein identity after microparticulation, Presented as Paper #685, IFT, Anaheim, June, 1990. Singer, N. S. and Desai, N., Structure and function of microparticulated proteins in low fat products, Presented as Paper #62, IFT, New Orleans, June 1992. Singer, N. S. and Moser, R. H., Microparticulated proteins as fat substitutes, Low Calorie Foods Handbook: Altschul, A. M., Ed., Marcel Dekker, New York, 1993, chap. 9. Singer, N. S.,Yamamato, S., and Latella, J., Protein product base, U.S. Patent 4,734,287, 1988. Singer, N. S., Wilcox, R., Podolski, J. S., Chang, H. H., Pookote, S., Dunn, J. M., and Hatchwell, L., Cream substitute ingredient and food products, U.S. Patent 4,985,270, 1991. Singer, N. S., Wilcox, R., and Podolski, J. S., Frozen dessert, U.S. Patent 4,855,156, 1989. Singer, N. S., Yamamato, S., and Latella, J., Viscous salad dressing, U.S. Patent 5,139,811, 1992a. Singer, N. S., Latella, J., and Yamamoto, S., Reduced fat yogurt, U.S. Patent 5,096,731, 1992b. Singer, N. S., Latella, J., and Yamamoto, S., Reduced fat sour cream, U.S. Patent 5,096,730, 1992c. Singer, N. S., Speckman, J., and Weber, B., Fluid processor apparatus, U.S. Patent 4,828,396, 1989. Stevens, S. S., and Harris, J. R., The scaling of subjective roughness and smoothness, J. Exp. Psychol., 64, 489, 1962. Stryer, L., Generation and storage of metabolic energy, Biochemistry, 3rd ed., W.H. Freeman & Co., New York, 1988, 313. Tang, P. S., Chang, H. H., Dunn, J. M., and Singer, N. S., A gel electrophoretic study of microparticulated protein (Simplesse®), FASEB, March, 1989. Wood, F. W., An approach to understanding creaminess, Die Starke, 26, 127, 1974.

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Chapter

9

The Use of Hydrocolloid Gums as Fat Mimetics Stuart M. Clegg CONTENTS 9.1 Introduction 9.2 Hydrocolloid Functionality in Foods 9.2.1 Thickening Properties 9.2.2 Gelling Properties 9.3 Galactomannans 9.3.1 Chemical Structure 9.3.2 Physical and Functional Properties 9.3.2.1 Locust Bean Gum 9.3.2.2 Guar Gum 9.3.3 Applications in Low-Fat Foods 9.4 Xanthan Gum 9.4.1 Chemical Structure 9.4.2 Physical and Functional Properties 9.4.3 Applications in Low-Fat Foods References

9.1 INTRODUCTION The term hydrocolloid can be used to describe many constituent components of plants and animals, and basically covers the whole range of polymeric materials occurring naturally. Of these, proteins and polysaccharides are traditionally the type of molecules considered as food hydrocolloids, and these long-chain biopolymer molecules have played a significant role in foodstuffs since ancient times on account of their texturizing and water-structuring properties.

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Historically, the utilization of food hydrocolloids such as gelatin, plant exudates, and starches dates back hundreds, if not thousands, of years and, indeed, for many of the exudates, the basic processes for their production and collection are similar to those used centuries ago. However, only with the development of the processed food industry over the last century has the commercialization of food hydrocolloids as food ingredients in their own right been witnessed. Other sources of polysaccharide gums have also been developed — in particular, land and marine plants in which the polysaccharide represents the reserve carbohydrate for the system and, in more recent years, biosynthetic gums produced via fermentation by microorganisms. The use of hydrocolloid gums in processed foods has traditionally been primarily as thickeners and gelling agents as a result of their ability to alter significantly the rheological properties of the solvent in which they are dissolved, even when used at very low concentrations. These viscosity-modifying effects occur as a result of the highmolecular-weight polymeric nature of hydrocolloids and the interactions that can occur between polymer chains when hydrocolloids are dissolved or dispersed. Considering the significant effects that food hydrocolloids can bring to the texture of a food product, it is not surprising that they have a role to play in fat-reduced products in which just the simple removal of fat, almost without exception, results in products with perceived inferior textural qualities, compared with their higher-fat counterparts. Indeed, all of the “tailor-made” fat mimetics discussed elsewhere in this book can be categorized as food hydrocolloids, and it is the processing to which the hydrocolloid has been subjected or its combination with other food ingredients that gives rise to the specific fat-replacing properties of each of the fat mimetics. In this chapter, the role of hydrocolloids, other than those specifically designed as fat mimetics, is discussed. The large number of food hydrocolloid systems available to the food technologist means that it would be impossible to discuss all the hydrocolloids in a chapter of this size. Consequently, the chapter is written so as to give a basic understanding of the functional properties of food hydrocolloids in food products, following which three hydrocolloids, locust bean gum, guar gum, and xanthan gum, are discussed in detail with reference to their functionality in fat replacement.

9.2 HYDROCOLLOID FUNCTIONALITY IN FOODS 9.2.1 THICKENING PROPERTIES All food hydrocolloids are polymers, and it is the high molecular weight of these ingredients, combined with the restrictions in flexibility between the monomer units within the polymer chains, that gives rise to their viscosifying properties. Generally, hydrocolloid thickeners exist in solution as disordered random coils continually changing their shape under the influence of Brownian motion (Rees et al., 1982; Morris, 1990a). Two extreme situations can be envisaged for a solution of a hydrocolloid, depending on the concentration (c). At low concentrations (Figure 9.1a), the polymer coils do not overlap and are free to move independently; this situation can be described as dilute solution conditions (Morris, 1984). The concentrated solution conditions are represented schematically in Figure 9.1c, and here the individual polymer coils interpenetrate one another to form an entangled polymer network. At some intermediate polymer concentration, the polymer coils just touch (Figure 9.1b) and this critical concentration at the onset of coil overlap is known as c*. The onset of coil overlap for any hydrocolloid solution is characterized by a marked change in the slope of a plot of viscosity against concentration for the hydrocolloid, and only at concentrations above c* does significant viscosity development occur (Morris,

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Figure 9.1 Schematic diagram of polymer coils in solution illustrating (a) dilute solution conditions where the polymer coils are free to move independently (cc*).

1991). At polymer concentrations below c*, the zero-shear viscosity (η0) increases more or less linearly with increasing concentration (a double logarithmic plot of η0 vs. c would typically have a slope of approximately 1.3 over this range). However, above c* the slope of the plot is typically around 3.3 and, hence, a slight increase in polymer concentration has a dramatic effect on viscosity above c*. The critical concentration at the onset of coil overlap is inversely related to the size of the individual coils (i.e., their hydrodynamic volume), which can be characterized experimentally by the intrinsic viscosity, [η], of the polymer. The molecular weight, the flexibility of polymer chains, and the amount of bound water associated with polymers determine, to a large extent, the hydrodynamic volume of polymer coils and hence their viscosifying properties. Although the type of hydrocolloid (i.e., chemical structure, molecular weight, flexibility, etc.) controls the viscosity of a given solution of the hydrocolloid by determining the hydrodynamic dimensions of the polymer coil, the dependency of viscosity on the extent of space occupancy by the polymer, which can be characterized by c[η] (i.e., c is proportional to the number of coils and [η] to the hydrodynamic volume), has been shown to have a general form for many different hydrocolloids (Morris et al., 1981). This is illustrated in Figure 9.2, where the logarithm of the zero-shear specific viscosity (ηsp) is plotted against the logarithm of c[η] for a number of different hydrocolloids. A sharp increase in the concentration dependency of viscosity is seen at c* (where the viscosity is about ten times that of water and c[η] ≈ 4).

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For model systems containing one hydrocolloid only, any hydrocolloid could thus be used to give the same final solution viscosity, providing the concentration of the hydrocolloid is correct. However, real food systems are not model hydrocolloid solutions but a complex matrix of different compounds with different physical structures, ionic strengths, pH values, etc. Consequently, when choosing the correct thickening agent for any particular food application, the food technologist must take this into account; factors such as interactions between hydrocolloids (be they synergistic or antagonistic), required concentration to give the desired viscosity and cost also have a role to play in determining the final choice of the hydrocolloid system(s) to be used. The general viscosity/concentration plot illustrated in Figure 9.2 applies to the zeroshear viscosities of hydrocolloid solutions, which is an index of the initial resistance to flow of the system. For solutions of small molecules, such as sucrose, viscosity, h, is independent of the shear rate (γ· ) at which it is measured and solutions such as this are described as possessing ideal (or Newtonian) behavior. Hydrocolloids, on the other hand, deviate vastly from Newtonian behavior in terms of their shear rate dependency of viscosity, and usually show a marked reduction in viscosity as the shear-rate of measurement is increased. The extent of this shear-rate dependency of viscosity (shearthinning behavior) is a function of the concentration of the polymer in solution. At concentrations below the coil overlap concentration, c*, polymer chains are essentially free to move independently through the solvent and the viscosity shows only a slight dependency on the shear rate of measurement (typically less than 30% over several decades of γ· ). For these dilute hydrocolloid solutions, the shear-thinning behavior arises as a result of individual polymer coils being stretched out under the influence of flow and consequently offering less resistance to movement (i.e., lower viscosity) (Morris, 1990a; Dickenson, 1992). As the concentration of a hydrocolloid solution increases above c*, the shear-rate dependency of the viscosity increases significantly, and typically a drop of several orders of magnitude is observed in viscosity over the shear-rate range of practical importance. When an entangled polymer network is present (i.e., above c*), application of flow requires that molecules wriggle through the entangled network of neighboring chains. At low shear rates, this can occur without a significant reduction in the number of entangled “cross-links” in the system (i.e., the time scale of disentanglement of the polymer chains caused by application of flow is similar to that of reentanglement between different chains) and viscosity is independent of shear rate at low shear rates. However, at high shear rates, the rate of disentanglement is greater than that of reentanglement and, hence, the cross-link density of the system decreases and consequently the viscosity falls. As with the concentration dependency of zero-shear viscosity, the shear-rate dependency of viscosity for many different random coil hydrocolloids can also be described in general form (Morris, 1991) by the simple empirical relationship η = η0 /[1 + (γ· / γ· 1/2) 0.76]

(9.1)

where η 0 = zero shear viscosity γ1/2· = shear rate required to reduce η to η0 /2 The concentrations at which most food hydrocolloids are utilized are above c* and therefore, the shear-rate dependencies of their viscosities are of significant importance in determining their functionality in any given food application. The shear rates to which a food hyrocolloid may be subjected during the “lifetime” of a food product are dependent on the exact product and process but typically range from zero during in-pack storage to extremely high values in some food processes such as valve homogenization. Between these

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Figure 9.2 Generalized concentration dependence of zero-shear specific viscosity for conformationally disordered random coil polysaccharides (different symbols represent different polysaccharides). (Reprinted from Morris, E.R., Cutler, A.N., Ross-Murphy, S.N., Rees, D.A. and Rice, J., Carbohydr. Polym., 1, Concentration and shear rate dependence of viscosity in random coil polysaccharide solutions, 5, 1981. With kind permission from Elsevier, Science Ltd., The Boulevard, Langford Lane, Kidlington OX5 1GB, U.K.)

two extremes, the product may be subjected to a host of other shear rates (e.g., during spreading, on mastication, due to shaking during distribution, etc.) and the role of the food technologist is to identify suitable hydrocolloids for incorporation into a specific formulation that gives correct functionality at all stages during the “lifetime” of the product.

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9.2.2 GELLING PROPERTIES In contrast to the thickening properties that all hydrocolloids possess to some extent, gelling properties are not universal among hydrocolloids, with “true” gel structures only being formed by a limited number of hydrocolloids. Essentially, a gel network is a permanently cross-linked polymer solution, with the polymer chains linked together to give a three-dimensional network structure in which solvent is entrapped. The cross-links in hydrocolloid gels are usually composed of ordered “junction zones,” in which chain segments from different polymer chains are packed in an ordered array of noncovalently bonded chain segments, with the remaining disordered sections of the polymer chains linking the ordered junction zones together (Figure 9.3). The nature of the junction zones varies from system to system, but they are usually composed of polymer chain segments with conformationally ordered structures the same as those present in the solid-state form of the hydrocolloid (Rees et al., 1982). Formation of such ordered structures under hydrated conditions involves considerable loss of conformational entropy, which must be compensated for by favorable enthalpic interactions between participating residues in the polymer chains (Morris, 1990a). Normally, end residues in the ordered sequences cannot fully participate in the noncovalent bonding interactions, due to a lack of appropriate residues with which to interact further along the disordered segments of the chain, and, consequently, the loss in entropy of these end residues is not fully compensated by a gain in enthalpy. The net effect of these “end effects” is that the junction zones need to be above a minimum critical length for stability, and their formation and dissociation occur as sharp, cooperative processes, brought about by changes in external variables such as temperature, pH, solvent quality, ionic strength, and/or the presence of specific ions, which can tip the ordered/disordered equilibrium in either one direction or the other (Morris, 1990a).

Figure 9.3 Schematic diagram of the polymer network structure of a hydrocolloid gel with noncovalently bonded ordered junction zones linking the polymer chains into a three-dimensional network.

Typical examples of the types of conformationally ordered junction zones that exist in hydrocolloid gels include helical structures such as the coaxial double helices found in carrageenan and agar gels, the double helical ordered structure of starch, and the

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collagen triple helical structure found in gelatin gels (Morris, 1986; Ledward, 1986). Other types of ordered structures are also found in hydrocolloid gels. In the calciuminduced gels of alginate and pectin (see Chapter 7C), the junction zones are formed by chain segments locked in a regular zig-zag shape with calcium ions sandwiched in the spaces between them to balance the negative charges on the polymer (Morris, 1986). For modified celluloses with a low degree of substitution and galactomannans, the chains can pack together with ordered ribbon-like structures similar to the fibrillar structure of insoluble native cellulose, but show some solubility on account of the substituent group on the main chain periodically disrupting the ordered structure (Morris, 1990a). In order for a gel structure to be formed, the ordered junction zones must terminate at some point so that the remaining unordered segments of the polymer chains are free to participate in other junction zones with other polymer chains and hence build up the threedimensional network structure. Termination of junction zones usually results from a change in primary structure along the polymer chain. Examples of changes in primary structure that terminate junction zones include a change from one type of residue to another type in polysaccharides with block-like character, irregularly spaced side chains, or the presence of residues that are geometrically incompatible with the ordered packing arrangement. Although true gelling characteristics are only shown by certain hydrocolloids, it should be noted that the distinction between a gel and a concentrated hydrocolloid solution is not always as clear-cut as it might seem and, from the viewpoint of the food technologist who wishes to utilize the properties of food hydrocolloids to give the correct rheological properties to the final food product, somewhat irrelevant. In general, hydrocolloid solutions and gels exhibit viscoelastic behavior (i.e., they possess both liquid-like and solid-like properties) and the type of behavior that such systems exhibit depends on the time scale of the process to which they are subjected. Resolution of the solid-like and liquid-like character of a material can be conveniently carried out using the technique of “mechanical spectroscopy,” in which a small oscillatory deformation is applied to the sample under test (Ross-Murphy, 1984; 1988). The stress generated by the sample in resisting the applied deformation can be resolved into components that are in phase and out of phase with the applied deformation. For a “perfect solid,” stress increases with the increasing extent of deformation (strain) and the in-phase stress generated is thus related to the solid-like character of a sample. This in-phase stress divided by the applied strain gives the modulus, G′ (known as the storage or elastic modulus). For a “perfect liquid,” resistance (stress) increases with increasing rate of deformation (which for an oscillatory system is maximum at the midpoint of the oscillation and zero at the extremes) and therefore, the out-of-phase stress divided by the applied strain gives the modulus, G″ (known as the loss or viscous modulus), which is a measure of the liquid-like response of the sample. The two parameters G′ and G″ are dependent on the frequency of the applied oscillation and in the technique of mechanical spectroscopy are measured over a range of frequencies. The ratio of the unresolved “complex modulus” G* = (G′ 2 + G″ 2)1/2 to the frequency of oscillation (ω ) gives a third useful parameter, the complex “dynamic viscosity,” η*, for characterization of viscoelastic materials. Typical hydrocolloid gels show mechanical spectra with the form illustrated in Figure 9.4a. The value of G′ is substantially higher than that of G″ , indicating the predominantly solid-like response of the sample, while both G′ and G″ , and hence G* show little, if any, frequency dependence. The dynamic viscosity (η * = G*/ω ) is inversely proportional to ω at all frequencies (as G* is essentially frequency-independent) and hence the slope of the plot of log η * against log ω approaches the theoretical limiting value of –1.

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Figure 9.4 Typical mechanical spectra of hydrocolloid gels and solutions showing the frequency (ω ) dependence of G′ , G″ and η* for (a) a strong gel, (b) a concentrated entangled random coil polymer solution and (c) a dilute hydrocolloid solution below the onset of polymer entanglement. (From Morris, E. R., in The Structure, Dynamics and Equilibrium Properties of Colloidal Systems, Bloor, D. M. and Wyn-Jones, E., Eds., Kluwer Academic Publishers, The Netherlands, 1990, 449. Reprinted with permission of Kluwer Academic Publishers.)

In order to form a hydrocolloid gel network, a minimum concentration (co) of the hydrocolloid is required (Morris, 1984; Dickenson, 1992). This minimum concentration varies according to the hydrocolloid in question and reflects the number of chains participating in junction zones, the size of the junction zones, the molecular weight of the polymer, etc. The concentration dependency of G′ for different gelling systems usually has the same form, with a high concentration dependency of G′ at concentrations just above co, which then decreases to a power-law relationship at higher concentrations. A typical mechanical spectrum of a concentrated solution of an entangled random coil hydrocolloid is illustrated in Figure 9.4b and is clearly quite different from that of the gelling system. At low frequencies, where there is sufficient time for entanglements to come apart in the period of an oscillation, G″ is higher than G″, indicating the predominantly viscous response of the sample, while h* remains constant. At higher frequencies, however, G′ crosses G″ , indicating a more solid-like (or gel-like) response, while η* decreases steeply with increasing frequency. This behavior at high frequencies is interpreted as arising due to insufficient time within the period of an oscillation for complete disentanglement of polymer chains and so the system essentially responds as a cross-linked gel (Morris, 1984).

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For completeness, the mechanical spectrum of a dilute random coil hydrocolloid solution below c* is shown in Figure 9.4c. It can be seen that h* shows little frequency dependency (i.e., similar in response to that of a Newtonian [perfect] liquid) and G″ is greater than G′ at all frequencies, indicating predominantly liquid-like behavior. The increase in G′ relative to G″ at high frequencies has been described as resulting from storage of energy by contortion of individual molecules into less energetically favored conformations (Morris, 1990a).

9.3 GALACTOMANNANS Plant seeds are a useful source of polysaccharides with gum-like properties, and of this type of polysaccharide, the family known as the galactomannans are the most widely used industrially. The three main galactomannan gums are guar gum, locust bean gum, and tara gum, but only the former two are extensively utilized, with tara gum not commercially exploited at present, and not approved for food applications (Glicksman, 1986). The use of locust bean gum dates back thousands of years, to when it was used in the process of mummification in ancient Egypt. Since that time, locust beans have been used as a food source, with exploitation of the functional hydrocolloid properties of locust bean gum by the processed food industry occurring over the last century. Locust bean gum is the common name applied to the gum found in the seeds of the carob tree (Ceratonia siliqua) and is, therefore, also sometimes referred to as carob gum. The carob tree grows extensively throughout the Mediterranean region and the dark brown locust bean pod (which contains several seeds from which locust bean gum is separated) is harvested annually (Seaman, 1980a). In contrast to locust bean gum, guar gum was introduced more recently to the Western world, as a result of a search aimed at finding replacements for other gums that became unavailable during the course of the second World War. However, commercialization of guar gum was very rapid after the war and its use as an industrial hydrocolloid now significantly outweighs that of locust bean gum (Glicksman, 1986). Guar gum is found in the seeds of two annual leguminous plants (Cyamposis tetragonolobus and psoraloides), which were traditionally harvested by hand in India and Pakistan. In the last 40 years, however, guar gum has established itself as a commercially viable crop suitable for modern mechanical farm technology (Seaman, 1980b). The production of locust bean gum and guar gum consists of a series of crushing, sifting, and grinding steps designed to separate the seeds from the pod and then the gum from the seeds. The gum is contained in the endosperm of the seed, with the endosperm making up 42 to 46% of the seed weight in locust bean gum (Seaman, 1980a) and 35 to 42% of the seed weight in guar gum (Seaman, 1980b). 9.3.1 CHEMICAL STRUCTURE Galactomannans are polysaccharides whose monomeric building blocks are composed of galactose and mannose. Both guar gum and locust bean gum have a chemical structure composed of a linear chain of 1,4 linked β -D-mannose with single-membered a-D-galactose units occurring as side branches, linked 1,6 with the main mannan chain (Figure 9.5). The two gums differ in their ratio of mannose to galactose (M:G ratio) and in the positions of the galactose side branches on the main polymer chain. Guar gum, which typically has an M:G ratio of around 1.5 to 2 (Glicksman, 1986), is considered to possess an almost alternating copolymer structure, with a galactose side-chain residue occurring approximately every other mannose residue, the galactose residues thus being evenly spaced along the length of the mannan chain. Locust bean gum, on the other hand, has

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a less highly substituted structure, with an M:G ratio of approximately 3.5. For locust bean gum, it is now generally considered that there are regions of galactose-substituted and unsubstituted mannan blocks along the polymer chain, but the number of residues in these blocks varies between samples (Morris, 1990b). The molecular weights of the two gums have been reported as being 310,000 (Herald, 1986a) for locust bean gum and 220,000 (Herald, 1986b) for guar gum. However, as with all gums, the molecular weights are polydisperse and are influenced by external factors such as climatic conditions during crop growth, botanical source, etc.

Figure 9.5 Primary repeating structure of galactomannans, showing the 1,4 linked β –D–mannose main chain with 1,6 linked α – D –galactose side branches. In locust bean gum, approximately 1 in 4 of the mannose units are substituted with galactose, while in guar gum, approximately 1 in 2 of the mannose units are substituted with galactose.

9.3.2 PHYSICAL AND FUNCTIONAL PROPERTIES 9.3.2.1 Locust Bean Gum In the solid state, galactomannans adopt an ordered two-fold conformation as a consequence of the almost fully extended 1,4-diequatorial-linked mannose residues (Winter et al., 1987). The chains pack together into flat sheet-like structures, with a spacing of approximately 0.9 nm between chains and about 3 nm between sheets in locust bean and guar gums. This intersheet spacing of 3 nm is significantly greater than for the parent mannan (0.72 nm) which has no galactose side branches on the polymer chain forcing the sheets apart (Morris,1990b). The type of packing and interactions in the solid form of galactomannans are of importance when considering their solution properties, as discussed below. Locust bean gum has only limited solubility in cold water but on heating to 80°C for 10 min it hydrates fully, resulting in a highly viscous, pseudoplastic (shear-thinning) solution. The lack of solubility at room temperature compared with guar gum occurs as a result of the higher M:G ratio in locust bean gum, and particularly the distribution of the galactose side branches on the main polymer chain (Morris, 1990b). Segments of the polymer chains that are deficient in galactose side-branches interact strongly with one another, and, consequently, energy (i.e., heating at 800C) is required if these secondary bonds are to be broken, allowing full solubility of the locust bean gum. Once in solution, locust bean gum solutions can be cooled down and the locust bean gum will remain in solution, providing the typical functional properties associated with

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polysaccharide thickeners. However, there is evidence in locust bean gums with low galactose content (e.g., M:G = 4.5) for gradual renaturation of interchain association with time, resulting in a tenuous, gel-like structure in concentrated solutions stored at ambient temperature for several days (Morris, 1990b). The renaturation process is accelerated at low temperatures and particularly by freeze/thaw cycles (Dea et al., 1977). At concentrations below those at which the gel-like structure is formed, freezing and thawing results in selective precipitation of the least substituted polymer chains and can therefore be used as a locust bean gum fractionation method. The main functional properties of locust bean gum when in solution arise as a result of its water-thickening capacity, and indeed locust bean gum is one of the most efficient hydrocolloid thickeners. When in solution, the polymer chains in locust bean gum exist in typical disordered random coil conformation, and the general shape of a viscosity/concentration plot is similar to that expected for such systems. However, for locust bean gum, a plot of zero-shear specific viscosity (ηsp) against the “coil-overlap parameter” c [η] does not superimpose on the general curve (Figure 9.2) expected for typical random coil polymer solutions. The transition from dilute solution behavior to concentrated solution behavior (c* transition) for locust bean gum occurs at a lower degree of space occupancy that for other random coil polymers (i.e., c* occurs at c [η] ≈ 2.5 for locust bean gum, but generally for random coil polymers occurs at c[η] ≈ 4). Furthermore, for locust bean gum, the viscosity at concentrations above c* is approximately proportional to c4, whereas for typical random coil polymers the viscosity is approximately proportional to c3.3. Below c*, however, the concentration dependency of viscosity is the same for locust bean gum as for other random coil polymers. The increased dependency of viscosity on concentration above c* for locust bean gum is interpreted as occurring as a result of normal polymer entanglements being augumented by chain-chain associations (similar to those in the solid state) at concentrations where polymer chains overlap (i.e., at concentrations above c*) (Morris, 1990b). From the point of view of the food technologist, the higher concentration dependency of viscosity of locust bean gum compared with other random coil thickeners is an advantage in that lower concentrations of locust bean gum can be used to give the same viscosity. In terms of response to shear, solutions of locust bean gum have zero yield values (i.e., they flow as soon as the slightest shear force is applied). Solutions are thus predominantly liquid-like in terms of their rheological characteristics although, at high concentration (2 to 3%), the high viscosities of locust bean gum solutions give them an almost gel-like appearance (Seaman, 1980a). Locust bean gum solutions behave as typical random coil hydrocolloids under the influence of shear, being pseudoplastic, with an initial shear-rate-independent plateau in shear rate vs. viscosity curves, followed by a rapid decrease in viscosity with further increase in shear rate. Unlike the concentration dependency of viscosity, the shear-rate dependency of viscosity of locust bean gum solutions is typical of random coil hydrocolloids and the viscosity against shear rate curve can be fitted using the generalized equation given earlier. Various external factors can cause locust bean gum solutions to be irreversibly degraded, with an associated loss of viscosity, as indeed is the case for most hydrocolloids. Prolonged heating at elevated temperatures and high rates of shear (with the extent of structure breakdown depending on the degree of shear and the time over which it is applied) are two obvious factors that can cause degradation and therefore must be considered by the food technologist when utilizing locust bean gum in any particular product application. The reduction in viscosity as a result of both heating and application of shear is a consequence of cleavage of the polymer chains and hence a lower average molecular weight.

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Locust bean gum, being a neutral polysaccharide, gives solutions whose viscosities are not significantly affected by salts commonly used in the food industry. The polymer is also stable over a fairly large pH range, from pH 3.5 to 11.0 (Herald, 1986a). Above and below these pH values, hydrolysis of the polymer takes place, resulting in a reduction in molecular weight and hence viscosity of solutions. The interaction of locust bean gum with other polysaccharides such as carrageenan and particularly xanthan gum is exploited by the food industry. When locust bean gum and xanthan gum are heated together, a solution with a viscosity higher than would be obtained from either of the individual gums is obtained. Furthermore, providing the gum concentrations are high enough, the solution gels on cooling to give thermoreversible gels. The molecular origin of these synergistic viscosity and gelling effects are discussed later in the section on xanthan gum. 9.3.2.2 Guar Gum The solid state of guar gum is basically the same as that of locust bean gum. In contrast to locust bean gum, guar gum dissolves at temperatures in the region of 25 to 40°C with stirring, and this solubility at lower temperatures occurs as a result of the lower M:G ratio in guar gum (Morris, 1990b). The lower M:G ratio in guar gum and the more even distribution of galactose residues along the mannan backbone mean that there are fewer galactose-deficient segments in the polymer chain, hence fewer intermolecular interactions between them and consequently, less heat required for solubilization of the polymer. The viscosity behavior of guar gum solutions is similar to that of locust bean gum solutions. Typical random-coil-like behavior is observed below the onset of coil overlap but the transition from dilute solution behavior to concentrated solution behavior (c*) occurs at a lower degree of space occupancy (c[η] ≈ 2.5), while the concentration dependency of viscosity above c* is greater than expected for typical random coil polymers. Unlike locust bean gum which has a significantly higher M:G ratio, there is little evidence for any renaturation of intermolecular structure on aging guar gum solutions. Guar gum solutions have zero yield values and their behavior under shear is typically random-coil-like, being pseudoplastic and showing the same general shear-rate dependency of viscosity as locust bean gum and other random coil hydrocolloids. As with locust bean gum, the main functional properties of guar gum arise as a result of its highly efficient thickening properties and water-binding capacity. In most applications, guar gum is utilized at concentrations below 1%, and at concentrations above this, solutions of guar gum, although still possessing zero yield value, have an almost gellike appearance due to their high viscosity and viscoelastic properties (Seaman, 1980b). Figure 9.6 shows the mechanical spectra of guar gum solutions at different concentrations. At low frequencies of oscillation and low concentrations, the response of the guar gum solution is predominantly liquid-like (i.e., G″ » G′ ) but, with increasing frequency of oscillation and concentration, the mechanical spectrum indicates a more solid-like response (i.e., G′ > G″ ). This crossover from predominantly liquid-like behavior to predominantly solid-like behavior is typical of concentrated solutions of random coil hydrocolloids, and as discussed earlier, has its origins in the inability of an entangled network of polymer chains to disentangle within the time scale of an oscillation. The effects of salts and pH on the viscosities of guar gum solutions are primarily the same as for locust bean gum solutions, with typical salts used in the food industry having little effect. The viscosities of guar gum solutions are reasonably stable between pH 3.5 and pH 9.0 (Herald, 1986b). The pH, however, does affect the rate of hydration of guar gum, with the maximum hydration rate occurring at a pH of about 8. As with locust bean gum, the effect of high shear rates and prolonged exposure to high temperatures can cause irreversible degradation of guar gum with the associated reduction in solution

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Figure 9.6 Frequency dependence of G′ (filled symbols) and G″ (open symbols) for guar gum solutions at different concentrations (1%, 2% and 3%). (Reprinted from, Robinson, G., Morris, E.R. and Ross- Murphy, S.B., Carbohydr. Res., 107, Viscosity-molecular weight relationships, intrinsic chain flexibility and dynamic solution properties of guar galactomannan, 17, 1982. With permission from Elsevier Science BV, Amsterdam Publishing Division, Sara Burgerhartstraat 25, 1055 KV, Amsterdam, The Netherlands.)

viscosity as a consequence of polymer chain cleavage. Guar gum also shows synergistic effects with other food hydrocolloids such as carrageenan and xanthan but, unlike locust bean gum, guar gum does not interact with xanthan gum to give thermoreversible gels, but gives only a synergistic viscosity increase (Morris, 1990b). 9.3.3 APPLICATIONS IN LOW-FAT FOODS The galactomannans, although not direct replacers for fats, are frequently used as tools in formulating reduced- and low-fat food products, where their main function is to imbibe water and control viscosity (Anon., 1991; Setser and Racette, 1992; Haumann, 1986). Their basic functional role in low-fat foods is, therefore, to a large extent the same as in traditional higher-fat products, but since low-fat products frequently contain significantly larger amounts of water than their higher-fat counterparts, the water stabilizing properties of hydrocolloids become increasingly important as the fat level is reduced. It has been suggested (Glicksman, 1991) that a three-ingredient system is necessary for a good fat mimetic: (1) a thickening agent for lubricity and flow control; (2) a soluble bulking agent for control of adsorption/absoption of the food onto the taste receptors of the tongue; and (3) a microparticulate to give the smoothness of the fat. Of these, the

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galactomannans fall into the first category and they are often used in low-fat formulations in conjunction with other ingredients possessing fat-replacing properties. Indeed, many second-generation fat mimetics are blends composed of a number of ingredients, each bringing its own functionality to the system, and these frequently contain either locust bean gum or guar gum as one of the functional ingredients (see for example Novagel®, a colloidal microcrystalline cellulose product containing 10 to 15% guar gum, described in Chapter 7A). Traditionally, the galactomannans have found application in food products such as frozen desserts, cultured dairy products, bakery products, and sauces and dressings, all of which now have low-fat versions in which the galactomannans have a functional role to play. The functional role of locust bean gum as a stabilizer in low-fat ice cream is the same as in a standard-fat ice cream. Once dissolved in the ice cream mix, locust bean gum produces a uniform viscosity which is relatively independent of temperature, while at the same time binding large amounts of water. During processing, the presence of locust bean gum promotes a fine ice-crystal structure in the ice cream, giving a short, smooth texture. The low temperature dependency of viscosity of locust bean gum gives the ice cream good heat-shock stability, with the locust bean gum maintaining the small icecrystal structure during periods of temperature fluctuation during storage (Herald, 1986a; Setser and Racette, 1992). Similarly, guar gum can be used as a stabilizer in low-fat ice creams, but unlike locust bean gum, it gives an ice cream with increased body and chewiness. These differences in final product texture obtained by using different stabilizers give the food technologist a method of creating different ice cream textures simply by varying the relative amounts of locust bean gum and guar gum in the formulation. In low-fat ice cream, the presence of a tailor-made fat mimetic in the formulation helps to give perceived fat-like properties (e.g., creamy mouthfeel) to the ice cream, but without the galactomanannan stabilizer controlling ice and sugar crystal growth and stabilizing and binding the excess water, the product would be of a far inferior quality. Another product type in which galactomannans have been traditionally utilized for their stabilizing properties are soft cheese type products and, here again, the reduced-fat versions make use of the good water-binding capacities of the galactomannans to prevent syneresis or weeping. In this type of product, locust bean gum in particular gives a unique desirable texture believed to be a result of complex formation of the locust bean gum with milk casein polymers (Herald, 1986a). Other ingredients, including other gums and fat mimetics, can be added to improve the textures of reduced-fat cheeses, making them more like the full-fat versions, but galactomannans, particularly locust bean gum, are the major stabilizers used in this type of product. Galactomannans also play a significant role in bakery products. This is because the galactomannans can pick up and hold water even through the baking process, thereby giving the low-fat product the softness and moistness associated with higher fat products (Anon., 1991). The incorporation of guar gum and locust bean gum into bakery products also provides an even crumb expansion as the product bakes, while the effect of guar gum on the viscosity of the aqueous phase helps to enhance the foam stability of cake batters (Glicksman, 1991). Consequently, low-fat bakery products stabilized by hydrocolloids possess larger volumes and finer, more uniform cell structure, similar to those of the traditional higher fat products.

9.4 XANTHAN GUM In contrast to the galactomannans, xanthan is one of a new breed of hydrocolloids, which are collectively categorized as fermentation or biosynthetic gums. Microorganisms produce

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three distinct types of polysaccharides: extracellular polysaccharides, structural polysaccharides, and intracellular storage polysaccharides. The extracellular polysaccharides (which can be found as discrete capsules surrounding the microbial cell or secreted as an amorphous slime into the surrounding medium) have been identified as possessing unique and functional hydrocolloid properties (Glicksman, 1982). The extracellular polysaccharides secreted are often complex in terms of their primary structure compared with more traditional gums such as galactomannans, and this frequently results in their possessing novel solution and gelling properties. Indeed, it is the novel rheological behavior of xanthan solutions that has made the commercialization of xanthan gum such a success. Xanthan is an extracellular polysaccharide from the microorganism Xanthomonas campestris, an organism originally isolated from the rutabaga plant, a member of the cabbage family. It was first isolated during an intensive screening program at the USDA Northern Regional Research Laboatory in Peoria in the late 1950s (Morris, 1990b). By 1964, commercial production of xanthan gum had begun. Authorization for the use of xanthan gum in food was granted by the Food and Drug Administration in 1969 following extensive animal feeding trials and, since this date, the functional properties of xanthan gum have been widely utilized in a whole range of different food product types (Pettitt, 1982). Current commercial production of xanthan gum is by large-scale aerobic fermentation. During fermentation it is necesary to maintain the pH within the range 6.0 to 7.5; if the pH is allowed to fall below a critical point of about 5.0, gum production either decreases sharply or ceases (Pettitt, 1982). Once fermentation is complete, the broth is pasteurized, followed by precipitation with isopropyl alcohol, drying, and milling to the desired particle size distributions. 9.4.1 CHEMICAL STRUCTURE Xanthan is composed of pentasaccharide repeating units as shown in Figure 9.7. The main polymer chain is composed of 1,4 linked β -D-glucose units (as in cellulose), but alternate residues on the backbone are substituted with a charged trisaccharide group linked 1,3 with the main chain, thus giving the pentasaccharide repeat unit. The trisaccharide side branches are composed of two mannose units and a glucuronic acid unit, with the glucuronic acid unit being sandwiched between the two mannose units. The terminal β-D-mannose unit in the side chain is glycosidically linked to the 4-position of β-D-glucuronic acid, which in turn is glycosidically linked to the 2-position of a-Dmannose. The structure is further complicated by the presence of acetate substituents on the 6-position of the nonterminal D-mannose unit and by the presence of pyruvate substituents joined by a ketal linkage to the 4-and 6-positions of the terminal D-mannose unit in the trisaccharide branch. In normal commercial xanthans, the degree of substitution is usually around 30 to 40% for pyruvate and 60 to 70% for acetate. However, there can be substantial variations in the extent of substitution within and between chains and, furthermore, there is also evidence that the number of side branches may be less (by up to 5%) than that expected from the idealized pentasaccharide repeating unit (Morris, 1990b). In terms of its conformation in solution, xanthan is different from most other polysaccharide thickeners in that it usually exists as a rigid rod-like conformationally ordered structure rather than as a random coil (Morris, 1991); this is the reason for the unique solution and gelling properties of xanthan, which will be discussed later. The ordered structure of xanthan in the solid state has been determined by X-ray fiber defraction studies, which show a five-fold helix with a pitch of 4.7 nm (Moorhouse et al., 1977; Okuyama et al., 1980). Two possible conformational structures have been proposed for

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Figure 9.7 Primary repeating structure of xanthan.

the ordered structure of xanthan: a single helix stabilized by the side branches packing along the backbone (Moorhouse et al., 1977), and a coaxial double helix in which both strands have a conformation close to that proposed in the single-helix model (Okuyama et al., 1980). There is supportive evidence for both models, with kinetic (Norton et al., 1984) and molecular-weight studies (Milas and Rinaudo, 1979) supporting the single stranded model, while light-scattering studies indicate that the mass per unit length is twice that expected for a single xanthan chain and hence support the double-stranded model (Liu et al., 1987). As yet, therefore, the exact conformation in solution remains unresolved. 9.4.2 PHYSICAL AND FUNCTIONAL PROPERTIES In contrast to most polysaccharide thickeners, xanthan gum in solution does not exist in a typical random-coil conformation but has a rigid helical ordered structure giving rise to the unique solution properties of xanthan. Solutions of xanthan are extremely pseudoplastic and show quite different shear-thinning behavior from the generalized shear-rate dependency of viscosity of typical random coil polysaccharides mentioned earlier. A double-logarithmic plot of viscosity vs. shear rate for xanthan at most salt concentrations of practical importance is linear, with no indication of a shear-rate-independent plateau at low shear rates, and with a slope substantially higher than the –0.76 predicted for random-coil-like behavior at high shear rates (Morris, 1990b). This high degree of pseudoplasticity results in xanthan solutions possessing extremely high viscosities (or effectively yield values) when not under the influence of shear. Consequently, xanthan solutions at rest can be considered as weak gels, as illustrated in Figure 9.8. The mechanical spectrum in Figure 9.8 has similar characteristics to those of a “true gel” (i.e., G′ > G″ at all frequencies, while both G′ and G″ show little variation with frequency and η* decreases steeply with increasing frequency). These gellike properties of xanthan solutions persist down to concentrations as low as 0.1% and this contributes to the effectivenes of xanthan gum as a stabilizing agent.

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Figure 9.8 Mechanical spectrum of a 2% xanthan solution showing the typical characteristics expected of a true gel. (From Morris, E.R. in Food Gels, Harris, P., Ed., Elsevier Applied Science, London, 1990, 291. With permission from Chapman and Hall Ltd., Scientific, Technical and Medical Publishers, Andover, Hampshire, England.)

Xanthan, therefore, like all polysaccharide solutions and gels, shows viscoelastic behavior. However, the uniqueness of xanthan results from the marked difference between its viscoelastic behavior under static conditions, when gel-like properties are present, and under conditions of shear, when freely flowing solutions are obtained. This combination of gel-like properties at rest and liquid-like properties under applied stress is of considerable practical value to the food technologist (Pettitt, 1982). The origins of the unusual solution properties of xanthan lie in its molecular structure, which determines the conformational behavior of xanthan. It is generally believed that the weak gel-like properties of xanthan solutions occur as a result of weak side-by-side association of ordered chain sequences from different molecules to give a tenuous threedimensional intermolecular network (Morris, 1991). For “normal” polysaccharide gels, bonding in the junction zones needs to be relatively strong to counter the considerable loss of conformational entropy as the fluctuating random coil chain is incorporated into the conformationally ordered junction zone. Consequently, the gels formed are quite strong. In xanthan, however, weak side-by-side enthalpically favored associations can

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occur between different molecules without substantial loss of conformational entropy, as the xanthan chains are already conformationally ordered. Consequently, the gel structure is only weakly bonded and can be easily disrupted by application of shear. The high viscosities at low shear rates of dilute xanthan solutions and the extremely pseudoplastic nature of xanthan are also a consequence of the rigid ordered structure. The more rigid structure of the conformationally ordered xanthan molecules over typical random coil polysaccharide molecules results in xanthan molecules having a greater hydrodynamic volume than would be the case for a random coil polysaccharide of the same molecular weight (that is to say, the length to breadth ratio of a rigid polymer molecule is considerably greater than that of a random coil polymer molecule). It therefore follows that the c* transition (onset of molecular overlap) for xanthan solutions occurs at low concentrations due to the large hydrodynamic volume of the molecules. This gives rise to high viscosities at low shear rates. At higher shear rates, however, the larger shear forces cause the elongated xanthan molecules to orientate in the applied shear field causing a relatively greater reduction in number of polymer entanglements than would be the case for a random coil molecule, and hence, the observed greater pseudoplasticity of xanthan. Although in most food applictions xanthan exists in a coformationally ordered helical form as a result of the electrolytes present in food, at high temperatures and low ionic strength the conformational order is melted out and xanthan then has typical fluctuating random coil-like behavior and a much lower viscosity. However, this disordered state of xanthan is not really relevant to the food technologist, except perhaps in high-temperature processing, where the reduction in viscosity on melting out the ordered structure can facilitate heat transfer, thereby shortening processing time (Pettitt, 1982). Xanthan has solution properties that are remarkably stable to the effects of both temperature and ionic strength, as might be expected for a rigid molecule. Indeed, a low concentration of electrolyte helps to stabilize the ordered form of xanthan by reducing electrostatic repulsion betwen carboxylate anions on the trisaccharide side branches, while at xanthan concentrations above 0.25%, a noticeable increase in viscosity and enhancement of weak gel properties with increasing salt concentration have been observed and attributed to a reduction in intermolecular repulsion, thereby promoting network formation through helix-helix association (Morris, 1990b). This is in contrast to typical random coil polyelectolytes, where the effect of increasing the ionic strength is to cause a reduction in intramolecular charge repulsion and hence cause the coil dimensions to collapse to some extent, with an associated reduction in viscosity (Smidsrød and Haug, 1971). The rigid helical structure of xanthan gum is also believed to play a role in stabilizing the xanthan molecule against the effects of acid and alkali degradation (viscosities of xanthan solutions are relatively unaffected by pH over the range pH 1 to 13), and from enzymic attack. This is thought to be related to the shielding of the glycosidic linkages in the polymer backbone by the trisaccharide branches which complex with the main chain in the ordered conformation (Pettitt, 1982). As mentioned previously, synergistic interactions occur between xanthan gum and both locust bean gum and guar gum. With locust bean gum, a thermoreversible gel is formed (providing the gum concentrations are high enough) with a melting temperature in the range 50 to 55°C (Pettitt, 1982). Maximum gel strength occurs at approximately equal ratios of the two gums and the gels themselves are relatively viscoelastic in nature, being similar to alginate-based gels and gelatin gels, rather than the more brittle agar and carrageenan gels. The locust bean gum/xanthan gels are true gels in a rheological sense, showing typical gel-like response and possessing definite yield values at significant

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strains. At concentrations below those required for gel formation (i.e., below approximately 0.5%), only a synergistic viscosity effect is observed between locust bean gum and xanthan gum, but this effect is still useful to the food technologist, allowing savings to be made in ingredient costs and modifications to be made to the rheology of food systems. The synergism between guar gum and xanthan gum is less strong, being limited to a synergistic viscosity increase with no gel formation (Morris, 1990b). Nevertheless, as for the locust bean gum/xanthan system below the gelling concentration, the synergistic viscosity effect of guar gum and xanthan gum is utilized in numerous food products. The synergistic effects between xanthan and galactomannans arise as a result of a specific interaction between the helical ordered structure of polysaccharides and the unsubstituted regions of galactomannan chains (Figure 9.9a), thereby forming “junction zones” which are linked together by disordered, more highly substituted segments of the galactomannan backbone (Dea et al., 1972; Morris, 1986; Morris, 1990b). The extent of interaction between xanthan molecules and galactomannan is dependent on the size and number of unsubstituted regions along the galactomannan molecule and the model therefore qualitatively predicts the observed lower degree of synergism in the more highly substituted guar/xanthan system than in the locust bean gum/xanthan system. However, although the model of specific interaction between xanthan and galactomannan molecules is now generally accepted, the exact conformation, the size of junction zones etc. in these mixed systems are still under investigation. An alternative model that would allow for the substituted regions of the galactomannan chain to be incorporated into the junction zones was proposed by McCleary (1979) and is schematically illustrated in Figure 9.9b. In this model, the galactose side branches on every other residue along the mannan backbone are all pointing away from the helical ordered structure. 9.4.3 APPLICATIONS IN LOW-FAT FOODS As with galactomannans, the role of xanthan gum in fat replacement is not as a direct fat mimetic but as a tool for controlling viscosity and texture and binding excess water. Indeed, xanthan can be used as a stabilizer in similar low-fat product types to those already mentioned under the section on galactomannans (e.g., frozen desserts, cultured dairy products, and bakery products). Frequently, a combination of xanthan gum and galactomannan is found to give better functionality in such products (as a result of the synergistic interactions) or at least the same functionality but at reduced cost. Commercially, many gum suppliers now supply gum blends for use in specific reduced-fat product types and these frequently include both xanthan and a galactomannan. One of the most successful food applications of xanthan as a stabilizer is in dressings, sauces and mayonnaises, where its weak gel properties (i.e., gel-like properties at rest and solution-like properties under the application of flow) are exploited to stabilize oil droplets and particulate material in the oil-in-water emulsions (Morris, 1991). Furthermore, such product types are ideal candidates for reduced-fat versions as the traditional products tend to be high in fat content, while consumers have demonstrated a willingness to use reduced-fat versions on a regular basis (Marsili, 1993). Indeed, reduced- and lowfat dressings and mayonnaises are undoubtedly among the most popular fat-reduced product types and can therefore be considered one of the major successes in the quest for low-fat, consumer-acceptable products. Hence, it is not surprising that xanthan, with its traditional stabilizing role in dressings and sauces, has been widely and successfully utilized in reduced- and low-fat versions of these products. The removal of oil and addition of water in a low-fat dressing requires that the oil phase be better stabilized if separation of the dressing is to be avoided on prolonged storage, while the viscosity needs to be suitably adjusted to give a similar consistency

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Figure 9.9 Schematic representations of the specific interaction in junction zones between galactomannans and helix-forming polysaccharides such as xanthan: (a) model proposed by Dea et al. (1972); (b) model proposed by McCleary (1979). (From Morris, V. J. in Functional Properties of Food Macromolecules, Mitchell, J. R. and Ledward, D. A., Eds., Elsevier Applied Science, London, 1986, 121. With permission from Chapman and Hall Ltd., Scientific, Technical and Medical Publishers, Andover, Hampshire, England.)

to that of the higher-fat counterpart. Incorporation of xanthan into the formulation can help on both accounts, giving relatively viscous solutions at low concentrations and stabilizing the disperse oil phase against coalescence through its gel-like properties at rest. In this manner, typical usage levels of xanthan, for example 0.1 to 0.4% (or lower when in combination with galactomannan), can help to make a small amount of fat go a long way. The highly pseudoplastic nature of xanthan gum also contributes to its effectiveness in low-fat dressings. In pourable dressings, the weak gel-like structure at rest is sufficient to give clear dressings an attractive visual appearance by suspending particulate matter throughout the shelf-life of the product but, on application of small shear forces (such as those experienced on pouring) the structure readily breaks down, allowing the dressing to flow from the bottle. On contact with the food, the tenuous gel structure rapidly sets up again so that the dressing clings to the food rather than draining off (Morris, 1991). Another advantage of xanthan gum in low-fat dressings is the nongummy mouthfeel and, associated with this, the good flavor release characteristics. These properties again arise as a consequence of the high degree of pseudoplasticity of xanthan, with the shear rates experienced in the mouth causing a significant reduction in the viscosity of the dressing, thereby giving maximum flavor impact. When developing a low-fat dressing, the food technologist is not only concerned with the physical and organoleptic properties of the dressing immediately following production, but also with any changes that may occur during the shelf-life of the product. In this regard, xanthan again has advantages over many other gums owing to the rigid helical ©1996 CRC Press LLC

ordered structure of the molecules which makes xanthan less susceptible to chain cleavage through acid hydrolysis, a factor that is particularly important in low pH dressings. In summary, xanthan is an extremely versatile hydrocolloid in terms of its functional role in a range of food product applications, possessing unique properties on account of its ordered molecular structure in solution that can be utilized in the formulation of reduced-fat products.

REFERENCES Anonymous, Quest for fat substitutes taking many routes, Inform, 2(2)115,1991. Dea, I. C. M., McKinnon, A. A., and Rees, D. A., Tertiary and quaternary structure in aqueous polysaccharide systems which model cell wall cohesion: reversible changes in conformation and association of agarose, carrageenan and galactomannans, J. Mol. Biol., 68, 153, 1972. Dea, I. C. M., Morris E. R., Rees. D. A., Welsh, E. J., Barnes, H. A., and Price. J., Associations of like and unlike polysaccharides: mechanism and specificity in galactomannans, interacting bacterial polysaccharides and related systems, Carbohydr. Res., 57, 249, 1977. Dickenson, E., An Introduction to Food Colloids, Cornell University Press, New York, 1992, chap. 3. Glicksman, M., Fermentation (biosynthetic) gums, in Food Hydrocolloids, Vol. I, Glicksman, M., Ed., CRC Press. Boca Raton, FL, 1982, 123. Glicksman, M., Plant seed gums, in Food Hydrocolloids, Vol. III, Glicksman M., Ed., CRC Press, Boca Raton, FL, 1986, 155. Glicksman, M., Hydrocolloids and the search for the “oily grail,” Food Technol., 5(10), 94, 1991. Haumann, B. F., Getting the fat out, JAOCS, 63(3), 278, 1986. Herald, C. T., Locust/carob bean gum in Food Hydrocolloids, Vol. III, Glicksman, M., Ed., CRC Press, Boca Raton, FL, 1986a, 161. Herald, C. T., Guar gum, in Food Hydrocolloiids, Vol. III, Glicksman, M., Ed., CRC Press, Boca Raton, FL, 1986b, 171. Ledward, D. A., Gelation of gelatin, in Functional Properties of Food Macromolecules, Mitchell, J. R. and Ledward, D. A., Eds., Elsevier Applied Science, London, 1986, 171. Liu, W., Sato. T., Norisuye, T., and Fujita, H., Thermally induced conformational change of xanthan in 0.01 M sodium chloride, Carbohydr. Res., 160, 267, 1987. Marsili, R., Strategies for creating low-fat sauces and dressings, Food Prod. Design, 3(8), 49, 1993. McCleary, B. V., Enzymic hydrolysis, fine structure, and gelling interaction of legume-seed D-galacto-Dmannans, Carbohydr. Res., 71, 205, 1979. Milas, M. and Rinaudo, M., Conformational investigation of the bacterial polysaccharide xanthan, Carbohydr. Res., 76, 189, 1979. Moorhouse, R., Walkinshaw, M. D., and Arnott, S., Xanthan gum — molecular conformation and interactions, in Extracellular Microbial Polysaccharides, ACS Symposium Series, 45, 90, 1977. Morris, E. R., Cutler, A. N., Ross-Murphy, S. N., Rees, D. A., and Rice, J., Concentration and shear rate dependence of viscosity in random coil polysaccharide solutions, Carbohydr. Polym., 1, 5, 1981. Morris, E. R., Rheology of hydrocolloids, in Gums and Stabilisers for the Food Industry, Vol. 2, Philips, G. O., Wedlock. D. J., and Williams, P. A., Eds., Pergamon Press, Oxford, 1984, 57. Morris, E. R., Industrial hydrocolloids, in The Structure, Dynamics and Equilibrium Properties of Colloidal Systems, Bloor, D. M. and Wyn-Jones, E., Eds., Kluwer Academic Publishers, 1990a, 449. Morris, E. R., Mixed polymer gels, in Food Gels, Harris, P., Ed., Elsevier Applied Science, London, 1990b, 291. Morris, E. R., Pourable Gels, IFI NR., 1, 32, 1991. Morris, V.J., Gelation of polysaccharides, in Functional Properties of Food Macromolecules, Mitchell, J. R. and Ledward, D. A., Eds., Elsevier Applied Science, London, 1986, 121. Norton, I. T., Goodall, D. M., Frangou, S. A., Morris, E. R., and Rees, D. A., Mechanism and dynamics of conformational ordering in xanthan polysaccharide, J. Mol. Biol., 175, 371, 1984. Okuyama, K., Aronott, S., Moorhouse, R., Walkinshaw, M. D., Atkins, E. D. T., and Wolf-Ullish, Ch., Fibre diffraction studies of bacterial polysaccharides, in Fibre Diffraction Methods, ACS Symposium Series, 141, 411, 1980.

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Pettitt, D.J., Xanthan gum, in Food Hydrocolloids, Vol. I, Glicksman, M., Ed., CRC Press, Boca Raton, FL, 1982, 127. Rees, D.A., Morris, E. R., Thom, D., and Madden, J.K., Shapes and interaction of carbohydrate chains, in The Polysaccharides, Vol. 1, Aspinall, G.O., Ed., Academic Press, New York, 1982, 195. Robinson, G., Morris, E.R., and Ross-Murphy, S.B., Viscosity-molecular weight relationships, intrinsic chain flexibility and dynamic solution properties of guar galactomannan, Carbohydr. Res., 107, 17, 1982. Ross-Murphy, S.B., Rheological methods, in Biophysical Methods in Food Research, Chan, H.W. S., Ed., Blackwell Scientific, Oxford, 1984, 138. Ross-Murphy, S.B., Small deformation measurements, in Food Structure — Its Creation and Evaluation, Blanshard, J. M. V. and Mitchell, J. R., Eds., Butterworths, London, 1988, chap. 21. Seaman, J. K., Guar gum, in Handbook of Water-Soluble Gums and Resins, Davidson, R. L., Ed., McGraw-Hill, New York, 1980a, chap. 14. Setser, C. S. and Racette, W. L., Macromolecule replacers in food product, Crit. Rev. Food Sci. Nutr., 32(3), 275, 1992. Smidsrød, O. and Haug, A., Estimation of the relative stiffness of the molecular chain in polyelectrolytes from measurement of viscosity at different ionic strengths, Biopolymers, 10, 1214, 1971. Winter, W.T., Song, B. K., and Bouckris, H., Structural studies of galactomannans and their complexes, Food Hydrocoll., 1, 581, 1987.

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Chapter

10

The Role of Emulsifiers in Low-Fat Food Products Eric Flack CONTENTS 10.1 Introduction 10.2 Yellow Fat Spreads 10.3 Biscuits (Cookies) 10.4 Cake 10.5 Ice Cream 10.6 Conclusion References

10.1 INTRODUCTION The use of polar lipids as emulsifiers in processed foods is not a particularly new idea. For instance, their use in the production of margarine has been known for more than 50 years although, no doubt, in the early days the choice was limited and the precise use arrived at was a process of trial and error. However, in recent times, not only have we learned very much more about their functionality, but also, by technical innovation, have improved the quality and variety available to us. For instance, through molecular distillation, interesterification, or ethoxylation, a whole range of products has emerged with many uses in food processing. Table 10.1 elaborates the range of products permitted for use in food in the European Community, U.S., and Japan at the time of writing. Within the particular headings, an even more varied range can be produced, depending upon the fatty acids used in the production (Flack and Krog, 1990). Some typical fatty acid compositions for monodiglycerides related to the oil feed stock used to prepare them are shown in Table 10.2. Emulsifiers are partial esters of fatty acids with chain lengths from C12 to C22, and polyvalent alcohols like glycerol, sorbitol/sorbitan, and sucrose or organic acids like

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Table 10.1

Food Emulsifiers Permitted in EC, Japan, and U.S.

Emulsifier types

EC No.

Lecithins

E 322

+

§ 184.1400**

Polyoxyethylene sorbitan monolaurate (polysorbate 20) Polyoxyethylene sorbitan mono oleate (polysorbate 80) Polyoxyethylene sorbitan mono palmitate (polysorbate 40) Polyoxyethylene sorbitan mono stearate (polysorbate 60) Polyoxyethylene sorbitan tristearate (polysorbate 65) Ammonium phosphatides (YN) Sodium potassium and calcium salts of fatty acids Magnesium salts of fatty acids Mono- and diglycerides of fatty acids (including distilled monoglycerides)

E E E E E E E E E

432 433 434 435 436 442 470(a) 470(b) 471

— — — — — — —

§ § § § §

172.515 172.840 178.3400*** 172.836 172.838 — § 172.863

+

§ 184.1501**

Acetic acid esters of mono- and diglycerides of fatty acids (Acetem) Lactic acid esters of mono- and diglycerides of fatty acids (Lactem) Citric acid esters of mono- and diglycerides of fatty acids (Citrem) Diacetyl tartaric acid esters of mono- and diglycerides of fatty acids (Datem)

E 472(a)

+

§ 172.828

E 472(b)

+

§ 1372.852

E 472(c)

+

—

E 472(e)

+

§ 184.1101**

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Japan

U.S. FDA 21 CFR*

Typical uses in food O/W emulsions, bakery products, cereals, confectionery, spreads, wetting and dispersion for vending products. O/W emulsions, ice cream, salad dressings, dairy products, wetting and dispersion for vending products, bakery products

Viscosity reduction in chocolate. Artificial lecithin Wetting and dispersion, O/W Emulsions, co-emulsifiers Crumb-softening, cake and cream aeration, foam stabilizing, amylose complexing, confectionery, ice cream, margarine, and spreads Alpha-tending, lubricant and release agent, increases foam stability and stiffness, coating agent Alpha-tending, dairy products, shortenings, desserts and toppings O/W and W/O emulsions, increases emulsion stability O/W emulsions, dough-strengthening, extrusion aid, fatsparing

Succinic acid esters of monoglycerides of fatty acids (SMG) Ethoxylated mono-glycerides Sucrose esters of fatty acids

—

+

§ 172.830

Bread emulsions — crumb-softening

— E 473

— +

§ 172.834 § 172.859

Bread emulsions — dough-strengthening O/W emulsions, bakery products, dessert products, cake aeration

Sucroglycerides Polyglycerol esters of fatty acids Polyglycerol polyricinoleate Propane-1,2-diol esters of fatty acids Thermally oxidized soya bean oil interacted with monoand diglycerides of fatty acids Sodium stearoyl lactylate (SSL) Calcium stearoly lactylate (CSL) Stearyl tartrate Sorbitan monostearate Sorbitan tristearate Sorbitan monolaurate Sorbitan mono-oleate Sorbitan monopalmitate

E E E E E

474 475 476 477 479(b)

+ + + + —

— § 172.854 — § 172.856 —

E E E E E E E E

481 482 483 491 492 493 494 495

— + — + + + + +

§ 172.846 § 172.844 — § 172.842 — § 178.3400*** § 178.3400*** § 178.3400***

* Central Federal Register. Title 21. ** GRAS — Generally recognized as safe. *** Production aids — not permitted as direct additives.

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O/W emulsions, cake aeration, dessert products W/O emulsions, viscosity reduction Alpha-tending, desserts and toppings, shortenings W/O emulsions for frying, release agent Crumb softening, dough-strengthening O/W emulsions Dough-strengthening Confectionery, desserts, yeast coating, o/w emusion Crystal-modifying, bloom-inhibiting Processing aids

Table 10.2

Typical Fatty Acid Compositions of Mono- and Diglycerides Fat source

Fatty acid

Lard or tallow

Myristic (C14:0) Palmitic (C16:0) Palmitoleic (C16:1) Stearic (C18:0) Oleic (C18:1) Linoleic (C18:2) C20 and higher Iodine value (approx)

1–3% 27–32% 3–5% 15–20% 36–43% 5–7% 40–55

Hydrogenated Hydrogenated Groundnut Sunflower lard or tallow soya bean oil oil oil 1–5% 28–34%

10–15%

10–12%

6–10

58–66%

85–90%

3–5% 40–55% 30–35% 5–10% 80

4–6% 18–28% 60–70%

1–2

1–2

105

From Flack E. A. and Krog, N., Lipid Technol., 2(1), 11, 1990. With permission.

lactic acid. Partial esters may also be esterified with organic acids such as acetic, citric, diacetyl tartaric, or succinic to form the wide range listed in Table 10.1. The world production of food emulsifiers has been estimated at between 185,000 and 250,000 tonnes (Als and Krog, 1990). Production of monodiglycerides from fat and glycerol is carried out by alkaline catalysis at high temperatures (circa 200°C). The proportions of fat and glycerol can be varied to obtain monoester contents of 30 to 60%, the latter being the limit for production from simple esterification. In many cases, the most important component of monodiglyceride is the monoglyceride, higher levels of which can be obtained by various means. The process preferred universally for large-scale production is high vacuum distillation which results in monoglyceride contents of 90% and higher. Monoglycerides and monodiglycerides are also the building blocks for production of other types of emulsifiers by reaction with organic acids or acid anhydrides to create acetic, citric, lactic, succinic, and diacetyl tartaric acid esters. The use first envisaged for emulsifiers was, as their name implies, to stabilize emulsions, whether they be water-in-oil (w/o) emulsions as in margarine or oil-in-water (o/w) emulsions as in the case of ice cream. Besides lowering the surface tension between components of multiphase systems, emulsifiers perform a wider range of functionalities, depending upon the type selected; these include foam stabilizing, dough conditioning, amylose complexing, and crystal modifying (Flack and Krog, 1990). Food emulsifiers are amphiphilic substances which, depending upon their chemical structures, possess both hydrophilic and lipophilic properties. This is often quantified in terms of their hydrophilic/lipophilic balance (HLB), and while this is a useful tool in developing simple technical emulsions, it is much less useful in food systems due to the complicated nature of food matrices. In general terms, emulsifiers are used either to facilitate processing or to improve the texture, consistency, and shelf-life of finished foodstuffs. As the structures of foods are rather complex, it is not possible in many cases to explain precisely the functions of emulsifiers at a molecular level. It is usual, therefore, to optimize emulsifier combinations and concentrations empirically. In emulsion-type foods, the function of emulsifiers is to form interfacial films which will contribute to the stability of emulsions against coalescence; thus, in this case, their effect upon long-term stability is of greater importance than their ability to reduce droplet particle size distribution. Interactions between emulsifiers and starch components in starch-based foods such as bread, flour, confectionery, processed potato, and pasta foods are also important.

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Emulsifiers possess many of the properties of fats and oils. They have an oily or fatty consistency, may be present in different physical forms (liquid, solid, crystalline) depending upon temperature, have lubricity and possess the texture and cohesiveness of fat. Emulsifiers form films or spread on surfaces, build or increase viscosity through hydration, and soften or weaken structures created by polysaccharides or proteins (Orthoefer and McCaskill, 1992). The mouthfeel properties of oils and fats are important characteristics to consider when reducing or replacing fat in formulations. Mouthfeel results from a combination of several basic parameters as shown in Table 10.3. Oils and fats may add to, modify, or reduce flavor and sweetness perception, and reduction of oils and fats can also have an effect upon processing and handling (Orthoefer and McCaskill, 1992). Furthermore, as the reduction of fat may be part of a general calorie reduction process, other bulk components such as sugar may also be reduced. Table 10.3

Parameters in Mouthfeel

Physical property

Sensory characteristic

Viscosity Lubricity Absorption/adsorption Cohesiveness/adhesiveness Waxiness

Thickness, body, fullness Creaminess, smoothness Physiological effect on taste perception Extension or delay of flavor perception Coating of palate, delayed flavor

From Orthoefer, F. and McCaskill, D., Inform., 3(12), 1270, 1278, 1992. With permission.

The desire to reduce fat without sacrificing organoleptic and textural properties has resulted in the development of fat replacers. However, emulsifiers can also play a significant role in enabling reformulation using lower levels of fat in processed water-inoil (w/o) emulsions and oil-in-water (o/w) systems (Flack, 1992). Typical examples of products in which proportions of fat can be reduced significantly, i.e., by 30% or higher, include yellow fat spreads, biscuits, cakes, baking emulsions, ice cream, and salad dressings.

10.2 YELLOW FAT SPREADS Traditionally and until the late 1960s, the yellow fats spread market was dominated by butter and margarine based on hard fats, which were used in the home for both spreading and baking. Both have levels of about 80% fat. Subsequently, spreads with fat levels reduced to about 40% became commonplace and more recently the emphasis has been on very low fat products with fat contents down to 20% or lower. Concurrently, the types of fat have changed, with a preference for the substitution of hard fats by soft fats with high proportions of polyunsaturated fatty acids. Margarine is essentially a stable product and the combination of milk proteins, lecithins, and/or saturated mono- and diglycerides used in production is more than adequate to ensure both stability and the desired eating characteristics (Flack, 1992). However, in reduced and very low-fat spreads, where the initial disperse phase is in much greater proportion than the continuous phase, several problems arise with instability, melt-down, and flavor release. While milk proteins are used in high fat products to improve mouthfeel and flavor, they also act as oil-in-water (o/w) emulsion stabilizers and thus their use in low fat products together with the considerable energy input needed to make this type of product

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can lead to phase inversion. Therefore, in low-fat spreads, it is necessary to use distilled monoglycerides instead of mono- and diglycerides for greater emulsion stability since monoglycerides have less interfacial activity than lecithin. Even when monoglycerides are used, added lecithin can further reduce the interfacial tension as shown in Figure 10.1 and thus increase the ever-present risk of phase inversion (Borwanker and Buliga, 1989). However, the work leading to this conclusion did not indicate the types of monoglyceride used, which has some significance.

Figure 10.1 Interfacial tension at 50°C of oil-in-water systems containing (a) 1.27% distilled monogylceride and (b) 1.27% distilled monoglyceride + 0.51% lecithin in the oil phase and 3.6% NACI in the aqueous phase. (From Borwanker, R. P. and Buliga, G. S., A.I.Ch.E. Symp. Series, Vol. 86, No. 277, 44, 1990. With permission.)

Problems with instability, melt-down and flavor release can be overcome by a combination of formulation and processing steps. Important factors in the formulation include the melting characteristics of the fat blend, the type and level of emulsifier, and the addition of thickeners to increase the viscosity of the water phase. To improve flavor release, low levels of whey protein, as later shown, can be used with the added advantage of a reduced pH of the water phase, thereby improving the keeping properties (unlike casein, whey proteins do not precipitate at low pH). The speed (i.e., rate of throughput) and emulsion temperature are also important factors in the stability of the spread. Madsen (1989) evaluated the stability of a 40% fat spread containing different combinations of emulsifiers by quantitative measurement of water separation as a factor of time, as shown in Table 10.4. In the case of a 20% fat spread (containing 4.0% skim milk powder, 3.0% gelatin, and 1.5% sodium alginate in the aqueous phase at pH 6.8), the presence of 0.8% distilled monoglyceride from sunflower oil (iodine value approximately 105) resulted in phase separation in the chiller, whereas the use of the same emulsifier at 0.5% in conjunction with 0.5% of polyglycerol ester of interesterified ricinoleic acid (iodine value approximately 85) produced a fine, stable spread with good spreadability and mouthfeel. The trial batches in both cases were made in a 3-tube Perfector pilot plant. Both examples indicate the potential instability of these emulsions

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Table 10.4 Effect of Types and Blends of Emulsifiers on the Stability of a 40% Fat Spread Water separation % after Levels of use 0.6% 0.6% Plus 0.2% 0.4% Plus 0.2%

Types of emulsifiers Distilled monoglyceride from vegetable oil Iodine value 80 Distilled monoglyceride from vegetable oil Iodine value 80 Polyglycerol ester of fatty acids Iodine value 80 Distilled monoglyceride from vegetable oil Iodine value 80 Polyglycerol ester of interesterified ricinoleic acid Iodine value 85

5 min 10 min 15 min 20 min 1.6

2.6

9.5

15.8

0

1.0

2.6

6.3

0

0

0

0

Note: Formulation of spread: water phase (pH 4.5): 56.4% water, 0.5% whey powder, 1.5% gelatin, 1.5% salt, 0.1% potassium sorbate. Fat phase: 39.2–39.4% fat blend, 0.6–0.8% emulsifier (as above), 4 ppm beta-carotene. From Madsen, J., World Conference on Edible Oils and Fats, AOCS, Maastricht, 1989. With permission.

and the differences in stabilizing effects of varying emulsifier combinations even at low dosages (Madsen, 1989). Although possible, it is more difficult to produce low-fat butter spread due to the hardness of butter oil at low temperatures. Spreads with a butterfat content of about 40% can be produced using 5.0% sodium caseinate in the water phase and 0.5% distilled monoglyceride with an iodine value of approximately 55 in the fat phase. However, the pH of the water phase cannot be lowered since the caseinate precipitates and loses its emulsifying properties and thus the keeping properties of the spread are limited. Alternatively, low fat butter spread can be produced using dairy cream with a fat content adjusted to the level desired in the finished spread and using a distilled monoglyceride with a high iodine value (80 to 105) added to the cream together with a thickening agent such as sodium alginate. Phase reversion, i.e., from o/w to w/o, can then be achieved in the tube chiller, using normal or slightly reduced cooling and utilizing 40 to 50% of the normal capacity. To achieve an adequate working effect, a high rotor speed in the tube chiller cooling cylinder is preferable (Madsen, 1989).

10.3 BISCUITS (COOKIES) The characteristics generally of importance in biscuits (cookies) include crispness, shortness, the correct texture for the biscuit type whether soft or hard (tough), and good flavor release. Changes in these characteristics can be related to the type of flour used, the proportions and types of sugar and fat used, the method of mixing, treatment of the dough, and the method of baking. Fats or shortenings are used to reduce the hardness of the biscuit and thus, simply reducing fat in the recipe results in a harder biscuit. This can also affect the cutting and machining of the dough whereby the finished biscuit may be misshapen. Furthermore, for the fat reduction to be of any value — either economically or dietetically — it needs to be significant, for example, 20 to 30% of the total fat. Originally, harder fats were used for biscuit production, but more recently, in view of the recommendations on fat consumption contained in various reports such as COMA, (Committee on Medical Aspects of Food Policy, DoH, U.K.) 1984, blends including

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highly unsaturated oils are used in order to increase the P/S ratio, that is, the ratio of polyunsaturated to saturated fatty acids which in itself affords a small reduction in fat without any significant loss of quality. Many trials have been undertaken to investigate the effect of emulsifiers on the texture of biscuits, especially in connection with the reduction of fat. Trials reported by Hutchinson and co-workers in 1977 were carried out using a cookie formula based on the American Association of Cereal Chemists (AACC) Method 10-50 (1962). The formula containing 13.5% fat, 47.6% flour, and 27.5% sugar as the main components, was used to screen the effects of various emulsifiers at levels increasing from 0.125% to 1% on flour weight. The dough was mixed in a Hobart N-50 mixer and baked in a reel oven at 204.5°C for 10 min. Samples were packaged in heat sealable poly bags and stored at room temperature (22 to 24°C) for three months. Initial texture readings were observed after 18 h of storage. Textural evaluations were measured using an Instron Texturometer, model 1132 with a 500 g combination load cell (tension/compression). Cookies were compressed to a depth of one half normal thickness or 4 mm, six cookies being evaluated for each emulsifier level and storage period. To observe the effects in a reduced-fat system, the formula was modified by (1) reducing the shortening by 20% (i.e., to 10.8%) and (2) increasing the water by one half of the weight of shortening removed (i.e., an increase of 32% in water level) necessary to maintain proper formula balance. Only two levels of each emulsifier (0.25 and 0.5% of flour weight) were tested in the reduced-fat cookies. The study showed that all the experimental cookies gave textural values below or were softer than the control. At the lower level of addition (0.25% of flour weight), the strongest softening effects were found using sodium stearoyl lactylate (SSL) and succinic acid ester (SMG) with medium effects observed with polyglycerol ester (PGE), ethoxylated monoglyceride (EMG), mono-di 40% and diacetyl tartaric acid ester (Datem), and with no appreciable effect using lactic acid ester (Lactem). At the higher level (0.5% of flour weight) an improved effect was seen with PGE, Datem, and Lactem, but poorer results with EMG, mono-di, and SSL. SMG gave similar results at both levels (Hutchinson et al., 1977). Unfortunately, as in many other early trials, exact specifications for the emulsifiers used in this study were not stated. This can be of great interest as esters can vary quite widely in their esterified acid levels, which can have a strong bearing on their effectiveness. Early trials at BBIRA (British Baking Industries Research Association), later FMBRA (Flour Milling and Baking Research Association, Chorleywood, U.K.), have been reported by Stevens in 1975. Reference was made to trials carried out in 1953 when glyceryl stearates (unspecified) were found to give satisfactory results in Osborne biscuits when used at a level of about one third of the amount of the fat that had been omitted, up to a maximum reduction of 20% of the fat (Stevens, 1975). However, trials in shortbread were reported as unsatisfactory at higher levels of replacement, even with up to half of the fat removed. By 1975, however, with a wider range of emulsifiers being available, trials were conducted using distilled monoglycerides and Datem at low levels in both semisweet 16% fat (Marie) and short dough 32% fat (Lincoln) biscuits, in which the fat calculated on flour weight was reduced by 20%, i.e., down to 12.8 and 25.6% fat on flour weight, respectively). Preliminary tests showed Datem to be the most effective emulsifier even though used at only half the levels of monoglyceride (i.e., 0.5 to 0.75% vs. 1 to 1.5%) and thus the follow-up investigations centered on this type of compound. The Datem paste used in the Stevens (1975) trials had a total tartaric acid content of 17 to 20%, an acid value of 70 to 90, and a saponification value of 380 to 425, both of the latter calculated as mg KOH/g product. The results of these trials indicated that goodquality biscuits with a reduced fat level could be produced with the aid of this emulsifier, as illustrated in Table 10.5. However, Stevens (1975) also noted in the accompanying

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Table 10.5

The Effect of Datem Emulsifier on Lincoln (L) and Marie (M) Biscuits with Fat Level Reduced by 20% Dough properties

Product type Lincoln Lincoln Lincoln Lincoln Marie Marie Marie Marie

Sample code

Fat % std.

Datem % fat

L1 L2 L3 L4 M1 M2 M3 M4

100 80 80 80 100 80 80 80

0 0 0.5 0.75 0 0 0.5 0.75

Consistency

Weight g ¥ 10

Stack height cm ¥ 20

Mean diameter cm

Density g/cc

Texturemeter seconds

Reflectance %

Satisfactory Dry and crumbly Crumbly Crumbly Optimum Tight Satisfactory Optimum

117.0 121.3 121.9 120.3 75.7 77.2 75.9 76.0

100.6 105.1 104.1 104.0 60.4 61.4 60.4 60.2

16.6 17.6 17.6 17.6 10.8 11.2 11.0 11.1

5.76 5.70 5.72 5.68 5.92 5.97 5.92 5.91

0.465 0.468 0.460 0.466 0.406 0.392 0.399 0.396

21 26 24 21 26 28 28 26

36 36 33 32 45 46 44 41

From Stevens, D. J., FMBRA Bull., 1, 1975. With permission.

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Biscuit properties

Dough piece wt. g ¥ 10

discussion that in the case of the 20% fat reduction in the Lincoln recipe, the amounts of ingredients were severely unbalanced and thus, adjustment of the ingredient levels as well as of the processing and baking conditions was advisable. Later work at FMBRA was more extensive and more detailed. In a report by Burt and Thacker (1981) details were given of trials carried out screening 20 commercially available emulsifiers as an extra ingredient in the FMBRA Lincoln biscuit recipe, having a fat content of 18% of dough weight (as against 32% of flour weight reported in the 1975 study by Stevens). The emulsifiers selected were those permitted for use in biscuits in the U.K. and which were thought to be of value in biscuit manufacture. Three alternative modes of addition were utilized — in the water, in the fat, or direct to the dough as the last ingredient at the creaming stage — and all at an inclusion rate of 1% in a firm dough in the initial trials. Following the elimination of some types for practical reasons, the main trials involved 13 emulsifiers at 0.4% level of addition. Details of the types used, the mode of addition and their effects upon dough firmness, dough piece weight, and biscuit hardness are shown in Table 10.6. Table 10.6

The Effect of Emulsifiers on Dough and Biscuit Properties % Change in Property Addition Level %

Mode

Dough firmness

Dough piece wt.

Biscuit hardness

1 0.4 1 0.4 1 0.4

Fat Fat Water Water Water Water

ns 45 75 39 36 40

2.8 4.4 3.1 2.2 1.5 1.7

18 22 28 23 18 ns

1 0.4 0.4 1 1 1 1 0.4 1 0.4 1 0.4

Fat Fat Fat Direct Direct Fat Water Water Fat Fat Water Water

ns ns ns ns 2.0 ns 84 30 ns ns 39 65

2.4 2.9 2.6 ns ns 2.3 3.4 2.4 1.9 2.0 2.6 4.1

ns ns 11 –29 –28 –36 ns ns ns ns ns ns

PGE*

0.4

Water

ns

1.4

–11

SSL

1 1 0.4 1 0.4

Direct Water Water Water Water

ns 99 114 ns ns

2.1 4.2 6.1 1.9 1.9

ns ns –19 ns ns

Emulsifier

Abbreviation

Monoglycerides

Mono (unsat) (sat)

Monodiglycerides Acid esters of monoglycerides: Lactic acid

Mono-di (sat)

Acetic acid Citric acid Diacetyl tartaric acid Sorbitan monostearate Sorbitan tristearate Polyoxyethylene sorbitan monostearate Polyglycerol monostearate Sodium stearoyl2-lactylate

Acetem Citrem Datem

Calcium stearoyl2-lactylate

Lactem*

SMS* STS* Polysorbate

CSL*

Note: ns = not significant. * No effect on these properties when added directly to the dough. From Burt, D. J. and Thacker, D., FMBRA Bull., 2, April, 1981. With permission.

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Since it had been established separately that increasing the level of fat in the recipe produced softer biscuits, it was judged that those emulsifiers which produced softer biscuits when added to the control recipe should be suitable alternatives to fat. The emulsifiers satisfying this criterion (Table 10.6) were Citrem, Datem, SSL, and PGE. On closer examination, the latter was found to have too small an effect to be of potential value as a fat replacer. Reductions of up to 30% in the level of fat in the control recipe were used for estimating the “trade-off” between emulsifier and fat. The effect of fat reduction on hardness in Lincoln biscuits, measured by the Baker Perkins Texturemeter, is shown in Figure 10.2, the reading for the control biscuit being about 12 s and for the 30% fat-reduced biscuit being about 16.5 s (Burt and Thacker, 1981). This represents an increase of about 37% in hardness relative to the control biscuit.

Figure 10.2 Effect on biscuit hardness of decreased levels of fat in the recipe, measured on Baker Perkins Texturemeter at constant force. (From Burt, D. J. and Thacker, D., FMBRA Bull. 2, April 1981. With permission.)

Further investigations by Burt and Thacker (1981) involved adding Datem via the fat, Citrem and SSL in the recipe water, and Datem and SSL by direct addition to the dough. In the latter approach, a modified recipe was used which adjusted dough water levels to obtain the same firmness as the control doughs. The results are shown in Table 10.7. Clearly, the mode of addition had a significant influence on the effectiveness of added emulsifiers in terms of fat replacement, while the convenience of direct addition offered distinct practical advantages. However, it should be noted that substitution of significant levels of fat by emulsifiers affects biscuit properties other than hardness and therefore emulsifiers should not be considered as equivalent to fat in all respects. The data in Table 10.8 show the differences in biscuit properties between biscuits prepared using the control recipe (18% fat on dough weight) and those containing 30% less fat (i.e., 12.6% fat on dough weight) and 0.5% Datem on an ingredients basis. Taste panel tests on biscuits with emulsifier levels from 0.25% to 1% after storage at 21°C and sealed in laminate for both 3 months and 6 months, did not reveal any serious off-flavors. The final conclusions from these trials were that the most effective and economical fat replacers were Datem and SSL when added directly to the dough and Citrem when added to the dough water (Burt and Thacker, 1981). A continuation of these trials reported by Burt and Thacker (1983) centered on Datem and SSL via two modes of addition each, i.e., Datem direct and via the fat and SSL direct and via the water. Particular note was made of the effect on biscuit hardness at varying levels. The difference in fat sparing effect, depending upon mode of application suggested in the earlier work, was not fully substantiated in this study. The conclusion finally reached was that these emulsifiers would be effective when added to the dough directly at low levels of 0.1 to 0.25% of the dry ingredients, up to a level of replacement ©1996 CRC Press LLC

Table 10.7 Emulsifier type

The “Trade-off” between Fat and Emulsifier in Short Dough Biscuits Mode of addition

Datem

Fat Direct Direct SSL Water Direct Citrem Water Emulsifier on fat basis**:

Calculated equivalence in fat% for addition* of emulsifier at: 0.125%

0.25%

0.5%

12 20 20 4 20 11 0.64%

19 — — 8 — 13 1.27%

30 — — 17 — 18 2.5%

Recipe FMBRA FMBRA Alternative FMBRA Alternative FMBRA

* Ingredients basis not including dough water. ** 0.74% for alternative recipe. From Burt, D. J., and Thacker, D., FMBRA Bull., 2, April, 1981. With permission.

Table 10.8 Effects on Biscuit Properties of a Datem Emulsifier at a Reduced Fat Level

Biscuit property Weight Thickness Width Length Moisture

Control biscuit 18% fat

Control, less 30% fat plus 0.5% Datem

% change in property

9.33 g 0.83 cm 5.73 cm 5.65 cm 1.6%

+7 +10 –2 –1 +45

8.72 g 0.75 cm 5.83 cm 5.71 cm 1.1%

From Burt, D. J. and Thacker, D., FMBRA Bull., 2, 1981. With permission.

of 20% fat. At higher levels of replacement, the dough became sticky which, it was felt, would cause problems in production. Separately, lecithin was tested at six levels from 0.0 to 1.0% but was found to have only a minor effect on biscuit hardness. For example, a level of 0.25% in the same recipe as above gave an average reduction in the Texturemeter reading of only 0.6 s correlating to a reduction of about 5% of total fat in the recipe. In recent years, biscuits in which the levels of fat have been reduced by more than 20% have been shown to be commercially viable with several brands now available. The substitution of normal shortening by very stable fat emulsions previously thought to be impractical, has enabled the production of satisfactory biscuits with significant reductions in fat levels, although the emulsion itself has presented problems in handling which, when solved, offers an interesting alternative. The work in this area is still under development.

10.4 CAKE The role of fat in the stabilization of air bubbles in cake batters was studied by Brooker (1993), using shortening containing emulsifier by the “all in” method. During mixing, fat crystals are coated with an interfacial layer of adsorbed protein (crystal-water interface) and absorb to the surface of the bubbles by a process which involves the fusion of the crystal-water interface with the air-water interface. The adsorption of fat crystals

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helps to stabilize large numbers of small bubbles which must expand without rupturing during baking if the batter is not to collapse. During heating, the fat melts and runs over the internal surface of the bubble, leaving behind the fat crystal-water interface to enable expansion. Almost all the air bubbles which ultimately create the texture in cake are incorporated during the preparation of the batter, and previous study has shown that the polymorphic form of the crystalline fat in the shortening affects the way in which air is incorporated. Thus, it has been observed that when the solid fat consisted primarily of b1 crystals, many small bubbles were stabilized, but when the much larger b crystals predominated, relatively little air was incorporated in fewer large bubbles (Brooker, 1993). This has led to the proposal illustrated in Figure 10.3 that the fat in the cooked batter forms a continuous layer on the inside surface of the air bubbles. Previously it had been reported that shortenings containing emulsifiers can stabilize larger numbers of small bubbles and can produce a finer crumb structure in the final product than shortening alone (Brooker, 1993). The size, shape, and number of the adsorbed fat crystals determine the area of interface that can be made available to the surface of air bubbles per volume of fat. Small fat crystals such as most b1 forms have a large surface area to volume ratio and are more efficient at contributing interface to air bubbles during cooking than would a similar weight of the larger b crystal form. Furthermore, the smaller b1 crystals usually have a lower melting point and melt faster than the larger b form and thus make available their fat-water interface more rapidly during baking. The incorporation of shortenings containing emulsifiers which help stabilize fat crystals in the lower melting forms such as Lactem and PGMS are, therefore, essential to ensure stable high volumes in cake batters when using lower levels of fat. This is, therefore, but a step away from the complete replacement of shortening by suitable emulsifiers which are stabilized in their lowest melting alpha form as aqueous dispersions. Of importance in this respect are the saturated distilled monoglycerides which disperse in water to form various mesophases at different temperatures (Krog, Riisom, and Larsson, 1988). This phenomenon is illustrated in Figure 10.4, from which it can be seen that the binary phase diagrams of saturated and unsaturated distilled monoglycerides differ considerably. Saturated distilled monoglycerides with 95% monoester form lamellar mesophases at 55 to 70°C while unsaturated products form predominantly cubic mesophases at room temperature (20°C+). The structure of various liquid crystalline phases formed by food emulsifiers, including monoglycerides, are shown in Figure 10.5. The latter is a highly schematic representation which only provides an indication of structure of the phases. The cubic model has been revised more recently and is much more complicated than the model shown in Figure 10.5 (Larsson, 1990). The process for the formation of the lamellar mesophase and (after cooling) the gel phase, is represented in Figure 10.6. At temperatures up to approximately 50°C, the monoglyceride remains in its stable b form, floating in water. At about 50°C, the monoglyceride starts to absorb water between the layers of polar groups and, if mixed in the right proportions of water to monoglyceride, a liquid crystalline phase is formed at 60 to 65°C. This is a fully homogeneous system where the monoglyceride molecules are oriented in a lamellar structure with water between their polar groups. At temperatures above 70 to 80°C, the monoglyceride transforms into a viscous isotropic phase in which there is a fixed ratio between the monoglyceride and water and where excess water is present as free water. The lamellar dispersion can be cooled to form an alpha crystalline gel, but it is unstable at room temperature and quickly transforms to a coagel (b crystals) unless used immediately. The efficiency of monoglycerides in various mesomorphic forms is shown in Table 10.9 (Tamstorf, 1983).

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Figure 10.3 Diagrammatic representation of the interfacial behavior of fat in the preparation and cooking of cake batter. (A) Adsorption of fat crystals to the air-water interface; (B) crystals melt during baking; (C) the oil runs over the internal surface of the bubble, thus releasing fatwater interface and permitting bubble expansion without rupture; (D) in the cooked batter, the fat forms a continuous layer on the inside surface of bubbles. (From Brooker, B. E., Food Structure, 12, 285, 1993. With permission.)

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Figure 10.4 Phase diagrams of distilled monoglycerides from (a) hydrogenated lard and (b) sunflower oil. (From Krog, N., Riisom, T., and Larsson, K., in Encyclopaedia of Emulsion Technology, Vol. 2, Becher, P., Ed., Marcel Dekker, New York, 321, 1988. With permission.)

While aqueous dispersions of monoglycerides are unstable, it is possible to stabilize the monoglyceride in the alpha form by the use of so-called alpha-tending emulsifiers (Acetem, Lactem, PGMS) and solvents such as propylene glycol to form a gel (Tamstorf, 1983). A typical cake gel system which can remain stable in the alpha form is composed of 20% saturated distilled monoglyceride (IV max 2) but with 8% distilled PGMS dissolved in 16% propylene glycol at 85°C, into which is slowly stirred a solution of 25% potassium stearate in glycerol (5%) and demineralized water (51%) also at 85°C, which is left to cool under slow agitation. Typical results obtained when using such a gel in a fat-free sponge cake, are shown in Figure 10.7. The actual dosage required in any recipe depends on the equipment used and the desired volume of the finished cake. In these trials, the batter was whisked once using a Hobart mixer. The importance of maintaining the emulsifier in its alpha crystalline form is illustrated in Figure 10.8. In these cases, simple dispersions were made as appropriate and whisked in a Hobart mixer. Such dispersions or gels can be utilized to maintain high levels of aeration in cake batters which have either reduced-fat levels or are entirely fat-free.

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Figure 10.5 Schematic structure models of lamellar, hexagonal, and cubic mesophases. (From Krog, N., Riisom, T., and Larsson, K., in Encyclopaedia of Emulsion Technology, Vol. 2, Becher, P, Ed., Marcel Dekker, New York, 321, 1988. With permission.)

Figure 10.6 Structure models showing (a) orientation of surfactant molecules in the crystalline state, (b) formation of a lamellar mesophase above Tc (Kraft Point) in the presence of water, and (c) the formation of a gel phase below Tc. The structure parameters d, da, dw and S can be measured by X-ray diffraction. (From Krog, N., in Food Emulsions, 2nd ed., Larsson, K. and Friberg, S. E., Eds., Marcel Dekker, New York, 127, 1990. With permission.)

10.5 ICE CREAM In most countries, legislative requirements stipulate minimum levels of fat in ice cream, the requirement varying between 5% and 12% (Flack, 1991). In the U.S. the standard product still requires a minimum of 10% fat but descriptor definitions for “lite” products, including low-fat and fat-free products, have been implemented. The opportunity to reduce fat, therefore, may be limited by legislation if the fat-reduced product is still to be called “ice cream” or by whatever name it is given in national legislation.

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Table 10.9 The Aeration Efficiency of Saturated Distilled Monoglycerides in Various Mesophases Type of mesophase Neat Viscous isotropic Viscous isotropic + H2O Dispersion Gel + H2O b crystals + H2O Mechanical dispersion at 68° in H2O (fresh)

Volume in cake batter ml/kg

Volume in cake cm3

1137 1112 1560 2970 2660 1370 1915

680 664 1012 1318 1200 810 1100

From Tamstorf, S., Grindsted Symposium, Beijing, 1983. With permission.

Figure 10.7 Effect of cake gel additions on batter and cake characteristics in fat-free sponge. (From Tamstorf, S., Grindsted Technical Paper TP 9-1e, presented at Grindsted Symposium, Beijing, September, 1983. With permission.)

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Figure 10.8 The aeration effects of distilled monoglyceride dispersions in alpha- and betacrystal forms.

Ice cream has a complex structure, being an aerated, partially frozen o/w emulsion in which the air bubbles are surrounded by absorbed fat globules. Thus, the fat not only provides a creamy taste but also helps create the structure of the ice cream. Emulsifiers, mainly monoglycerides (40 to 90% monoester), are used at the levels needed to provide approximately 0.21% 1-monoglyceride in the mix in order to destabilize the fat globule membrane structure formed following homogenization and leading to partial churningout in the freezer, which then facilitates foaming and improves air cell distribution (Flack, 1988). The destabilization process which takes place during ageing of the mix at 5°C involves desorption of interfacially bound protein (casein). Simultaneously, an increase in fat globule crystallization occurs which also amplifies the rate of protein desorption. The removal of adsorbed proteins increases the hydrophobicity of the fat globules and promotes their agglomeration and orientation around the air cells in the finished ice cream. The desorption of protein is related to the temperature of the mix. At temperatures above 40°C, the amount of protein adsorbed to the fat phase is high; when the temperature of the emulsion is lowered, the amount of adsorbed protein is reduced (Krog, 1992). Studies of the interfacial tension in o/w systems with or without emulsifiers dispersed in the oil phase and with milk proteins dissolved in the water have shown that temperature has a very pronounced effect on the surface activity of monoglycerides (Barford et al., 1993). At high temperatures, the solubility of monoglycerides in the oil phase is high and the reduction in surface tension minimal. However, upon cooling, the solubility decreases while the adsorption of monoglycerides at the o/w interface increases, resulting in lower surface tension. When monoglycerides are present, the interfacial tension decreases at low temperatures to values below that of the protein film, and consequently the increased adsorption of monoglycerides displaces the protein molecules. The interrelationship between decrease in interfacial tension, protein desorption, fat crystallization, and the agglomeration of fat globules due to increased hydrophobicity, is shown in Figure 10.9 (Barford et al., 1993) An important element in the processing of ice cream mix is homogenization, during which the fat is distributed as small globules. The particle size distribution of the fat is affected by both the temperature at which homogenization is carried out and the pressure ©1996 CRC Press LLC

Figure 10.9 Changes in interfacial phenomena, such as interfacial tension, protein desorption and fat crystallization related to agglomeration of fat globules in ice cream as a function of a decrease in temperature with (+E) and without (-E) added monoglyceride emulsifier. (From Barford, N. M., Krog, N., Larsen, G., and Buchheim, W., Fat Science Technol., 24, 1993. With permission.)

at which it takes place. The optimum temperature usually recommended is 75 to 85°C, and the pressure varies according to the fat content in order to obtain the preferred results organoleptically, including mouthfeel (cold or warm eating), consistency (soft, brittle), creaminess, and melt-down. Optimum homogenization pressures related to fat percentages have been evaluated as shown in Figure 10.10 which also indicates the differing pressures suggested for similar fat levels derived from different origins (Flack, 1983). Trials using pressures up to 40 kp/cm2 above and below the optimum have shown that increased pressures result in quicker melt-down and less churning-out. On the other hand, ice cream that has been subjected to higher pressures is colder-eating, more brittle, and has a looser texture. The explanation for these phenomena is found in variations in particle size distribution. The effect of varying homogenization pressures on the particle size of a mix containing 10% fat derived from double cream is shown in Table 10.10 (Larsen, 1988). When surface areas are compared with FFE (free fat estimated) values, a clear correlation can be seen, as illustrated in Figure 10.11 (Larsen, 1988). The explanation for this is that when the surface area of the fat globule is increased, the ratio between emulsifier and protein on the fat globule surface changes. The concentration of the monoglyceride is reduced relatively and thus the amount of churned out fat is also reduced. This leads to reduced air stabilization and quicker melt-down. As previously indicated, monoglycerides are the preferred emulsifiers for ice cream production, although polysorbates may be used at low levels in combination with monodiglycerides, as they strongly influence agglomeration. It must also be noted that with

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Figure 10.10 Optimum homogenizing pressures for ice cream mixes of varying fat type and content. (From Flack, E. A., Ice Cream and Frozen Confectionery, Ice Cream Alliance, Ltd., London February 1983. With permission.)

Table 10.10 The Effect of Varying Homogenizing Pressures on Particle Size of a 10% Fat-Based Ice Cream Homogenizing pressure, kp/cm2

140

160

180

200

220

Average size, µm Variance, µm

1.67 1.02

1.25 0.75

1.14 0.70

1.08 0.67

1.00 0.55

From Larsen, G., Paper presented at Inter-Ice 1989, Selingen. With permission.

such high water levels in the product, hydrocolloids play an important role in the structure and stability of the ice cream due to their influence upon the rheological conditions of the water phase (see Chapter 9). From all these observations, it can be seen that ice cream with lower fat levels can be produced by varying the balance of raw materials within the recipe and by adjusting processing conditions. Examples of standard, low-fat and non-fat ice cream are shown in Table 10.11, indicating the variations required to achieve optimum results and to ensure organoleptic acceptability. Other food products in which an appreciable reduction in fat ©1996 CRC Press LLC

Figure 10.11 Churning out as a function of surface area. (From Larsen, G., Paper presented at Inter-Ice 1988, Solingen, November 1988. With permission.)

Table 10.11 Creams

Composition of Standard, Low-Fat, and Fat-Free Ice Standard ice cream

Butterfat % Msnf % Sugar % Corn syrup solids % Monoglyceride (60%) % Stabilizer blend % Total solids % K/cal/100 g Homogenization kp/cm2

10.0 10.5 12.0 5.0 0.35 0.15 38.0 204 160

Milk ice 3.0 11.2 12.0 6.0 0.49 0.21 32.9 149 220

Non-fat dessert 0 11.8 12.0 7.0 0.6 0.4 31.8 130 240

can be achieved by utilizing the emulsifier functionalities described in the foregoing, often in association with appropriate hydrocolloids, include desserts and toppings, dairy analogues, dressings, sauces and pastries.

10.6 CONCLUSION From this chapter, some general conclusions relating to the use of emulsifiers in fat replacement can be drawn. First, a reduction in fat requires changes in both formulation and processing to maintain quality comparable to the original product. Second, while oils and fats may be used more efficiently in combination with emulsifiers, activation of emulsifiers, for instance by hydration, to form dispersions and gels, may be required for optimum performance, in which case a change in the composition of emulsifier blends toward more hydrophilic properties may be necessary. The art of fat reduction may often be in the creation of fat-like rheological properties by changing the aqueous components in food systems. ©1996 CRC Press LLC

REFERENCES ALS, G. and Krog, N., Emulsifiers as food processing aids, in World Conference on Oleochemicals into the 21st Century, Applewhite, T. H., Ed., AOCS, Kuala Lumpur, 67, 1990. Barford, N. M., Krog, N., Larsen, G., and Buchheim, W., Effects of emulsifiers on protein-fat interaction in ice cream mix during ageing 1: Quantitative analysis, Fat Sci. Technol., 24, 1993. Borwanker, R. P., and Buliga, G. S., Emulsion properties of margarines and low fat spreads, A.I.Ch.E. Symp., Vol. 86, No. 277, 44, 1990. Brooker, B. E., The stabilization of air in cake batters — the role of fat, Food Structure, 12, 285, 1993. Burt, D. J. and Thacker, D., The use of emulsifiers in short dough biscuits, FMBRA Bulletin 2, April, 1981. Burt, D. J. and Thacker, D., Further investigations of emulsifiers in short dough biscuits, FMBRA Bulletin 5, October, 1983. Flack, E. A., Important factors which affect homogenisation efficiency, in Ice Cream and Frozen Confectionery, Ice Cream Alliance Ltd., London, February, 1983. Flack, E. A., Europe — Ice cream, legislative requirements, Paper presented at Grindsted Technical Seminar, ICA Exhibition, Glasgow, 1991. Flack, E. A., The role of emulsifiers in reduced fat and fat-free foods, in Food Technology International Europe, Turner, A., Ed., Sterling Publications Limited, London, 1992, 179. Flack, E. A., The Role of Emulsifying and Stabilizing Agents in Ice Cream, Grindsted Technical Paper TP 210-1e, 1988. Flack, E. A. and Krog, N., Emulsifiers in modern food production, Lipid Technol., 2(1), 11, 1990. Hutchinson, P. E., Barocchi, F. and Del Vecchio, A. J., Effect of emulsifiers on the texture of cookies, J. Food Sci., 42(2), 399, 1977. Krog, N., Riisom, T. and Larsson, K., Applications in the food industry, in Encyclopaedia of Emulsion Technology, Vol. 2, Becher, P., Ed., Marcel Dekker, New York, 1988, 321. Krog, N., Food emulsifiers and their chemical and physical properties, in Food Emulsions, 2nd ed., Larsson, K. and Friberg, S. E., Eds., Marcel Dekker, New York, 1990, 127. Krog, N., The role of low-polar emulsifiers in protein-stabilized emulsions, in Emulsions — a Fundamental Practical Approach, Sjöblom, J., Ed., Kluwer Academic Publishers, The Netherlands, 61, 1992. Larsen, G., The principles of homogenization of an ice cream mix, Paper presented at Inter-Ice ‘88, Solingen, November, 1988. Larsson, K. and Dejmek, P., Crystal and liquid crystal structures of lipids, in Food Emulsions, 2nd ed., Larsson, K. and Friberg, S. E., Eds., Marcel Dekker, New York, 1990, 97. Madsen, J., Low-calorie spread and melange production in Europe, in World Conference on Edible Oils and Fats, AOCS, Maastricht, October, 1989. Miller, A. R., Ferguson, E. F., Thacker, D. and Wheeler, R. J., Fat reduction in biscuits and crackers, FMBRA Report No. 140 Part 2, December, 1988. Orthoefer, F. and McCaskill, D., Emulsifiers and their role in low-fat and no-fat processed foods, Inform, 3(12), 1270, 1278, 1992. Stevens, D. J., The use of emulsifiers in biscuits, FMBRA Bulletin 1, February, 1975. Tamstorf, S., Emulsifiers for bakery and starch products, Grinsted Technical Paper TP 9-1e, presented at Grindsted Symposium, Beijing, September, 1983.

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Chapter

11

The Role of the Bulking Agent Polydextrose in Fat Replacement Helen L. Mitchell CONTENTS 11.1 11.2 11.3 11.4 11.5

Introduction and Historical Perspective Production Process and Patent Status Chemical Composition Physical and Functional Properties Applications 11.5.1 Reduced-Fat Pastry 11.5.2 Other Applications 11.6 Nutritional and Toxicological Aspects 11.7 Legislative and Labeling Status References

11.1 INTRODUCTION AND HISTORICAL PERSPECTIVE Polydextrose is a unique material that was invented by Dr. Hans Rennhard at Pfizer Central Research Laboratories, U.S., in the mid-1970s (Rennhard, 1975). Polydextrose is a low-calorie bulking agent which can replace all or part of the sugars and some of the fats in foods while maintaining a pleasant texture and mouthfeel. This multifunctional food ingredient can also be used as an humectant, texturizer, thickener, stabilizer, and cryoprotectant. Polydextrose is a complex carbohydrate made from glucose, sorbitol, and citric acid, and it has been used in human food as a low-calorie bulking agent since the early 1980s. Polydextrose, improved polydextrose (Litesse®), and super-improved polydextrose (Litesse® II) are currently manufactured by Pfizer Food Science in the U.S.

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11.2 PRODUCTION PROCESS AND PATENT STATUS Polydextrose is prepared by a vacuum melt process involving polycondensation of glucose in the presence of small amounts of sorbitol and citric acid in the ratio 89:10:1, respectively. Sorbitol acts as a plasticizer and citric acid as a catalyst in the polymerization. It is important that the molecular size of the polymer is controlled (MW about 5,000) during the manufacturing process in order to restrict the formation of large molecular weight molecules. This control prevents the formation of insoluble materials and results in the highly water soluble nature of polydextrose (Allingham, 1982; Beereboom, 1981). The polymer is subjected to various clean-up procedures to produce several qualities of polydextrose. The process was patented by Rennhard in 1975.

11.3 CHEMICAL COMPOSITION Polydextrose is a randomly linked polymer of glucose that contains sorbitol end groups and an occasional citric acid moiety attached by an ester linkage. The random bonds in the polymer (both alpha and beta and predominately 1–6, but with some 1–2, 1–3, 1–4 and 1–1 bonds) creates a structural compactness and complexity that prevents mammalian digestive enzymes from readily hydrolyzing the molecule. A hypothetical structure for a typical polydextrose oligomer is shown in Figure 11.1.

Figure 11.1 The chemical structure of polydextrose. (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

Polydextrose has an average degree of polymerization of 8 glucose units and a molecular weight below 5,000 (Allingham, 1982; Beereboom, 1981). Beside the polymer, polydextrose contains small quantities of unreacted monomers (glucose and sorbitol), low levels of 1,6-anhydroglucose (levoglucosan), and trace amounts of 5-hydroxymethylfurfural. The latter products are formed from glucose during the manufacturing process (Murray, 1988; Moppett, 1991; Thomas, 1991). All starting materials

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used in the manufacture of polydextrose are food grade products. Polydextrose is supplied to the industry in compliance with the Joint Expert Committee on Food Additives (JECFA) and the Food Chemical Codex compendial specifications.

11.4 PHYSICAL AND FUNCTIONAL PROPERTIES Polydextrose is an odorless, white to light cream amorphous powder, and its physicochemical properties are summarized in Table 11.1. It has virtually no sweetness and an energy value of only 1 kcal/g. Unlike the polyols, polydextrose takes part in the Maillard reaction with amino acids, similar to reducing sugars, so allowing the characteristic flavors of caramel and toffee to develop. Polydextrose, improved polydextrose (Litesse), and super-improved polydextrose (Litesse II) have positive heats of solution (9 kcal/g), unlike sucrose (–4.3 kcal/g) and most of the polyols (–8 to –35 kcal/g). Table 11.1 The Physical and Chemical Properties of Generic Polydextrose Molecular weight range

Appearance Odor Melting point Solubility (25°C) Viscosity (25°C, 50%w/w) Heat of solution Water activity (20% w/w) pH in water (100g/liter) Titratable acidity Caloric value Relative sweetness Water Sorbitol Glucose a

162–5,000 88.1% 5,000–10,000 10.0% 10,000–16,000 1.2% 16,000–18,000 0.1% White-cream amorphous powder None 130°C 80% w/w 33.2 centipoise 9 Kcal/g 0.992 2.5–3.5 0.14–0.16 meq/g 1 kcal/g None Max 4% Max 2%a Max 4%a

Anhydrous, ash-free basis.

Courtesy of Pfizer Ltd., Kent, United Kingdom.

Polydextrose is highly soluble in water to approximately 80% w/w at 20°C. As shown in Figure 11.2, polydextrose is more soluble than any of the polyols. When making up aqueous solutions of high concentration, it is recommended to use a slow rate of addition, moderate heat (35 to 40°C) and high shear mixing. Preblending with other water soluble ingredients also aids in the rate of solution of polydextrose. Polydextrose solutions are clear, but at high concentrations exhibit a characteristic yellow color. This color has not been found to be a problem in most food product applications. Solutions of polydextrose have a higher viscosity than sucrose or sorbitol solutions at equivalent concentrations and temperatures. This characteristic enables polydextrose to provide the desirable mouthfeel and textural qualities so important when replacing sugars and fats. The changes in viscosity with increasing concentration and temperature for polydextrose, sucrose, and sorbitol are compared in Figures 11.3 and 11.4.

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Figure 11.2 A comparison of the solubility of polydextrose, sucrose, and selected polyols at 20°C. (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

Figure 11.3 Concentration/viscosity relationship of polydextrose, sucrose, and sorbitol at 25°C. (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

Polydextrose can function as an humectant, helping to slow down undesirable changes in the moisture content of foods. Figure 11.5 illustrates how polydextrose (Litesse and Litesse II) absorbs moisture under conditions of high relative humidity until an equilibrium is reached. Polydextrose solutions have only a slightly higher water activity than sucrose solutions at any given concentration and temperature. Therefore, since polydextrose is not sweet, it may be used in savory applications as a means of controlling the water activity of a product and hence helping to prolong its shelf life. Freezing point depression is an important function, required for the preparation of creamy and palatable frozen desserts. In conventional frozen products, sucrose and other bulk sweeteners are used to produce the correct consistency and mouthfeel of the finished product. The lower the molecular weight of an ingredient, the greater its effect on the ©1996 CRC Press LLC

Figure 11.4 Temperature/viscosity relationship of 70% solutions of polydextrose, sucrose, and sorbitol. (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

Figure 11.5 A comparison of the moisture pick-up of Litesse, selected sugars, and polyols at a Relative Humidity of 66% (30°C). (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

freezing point depression. Polydextrose has a higher average molecular weight and therefore has a reduced and favorable effect on the freezing point depression compared with smaller molecules such as sucrose or sorbitol, as shown in Figure 11.6 (Baer and Baldwin, 1984 and 1985). Polydextrose has also shown some potential as a cryoprotectant in fish and beef surimi (Park, 1986; Park and Lanier, 1987); in these products, polydextrose has some advantages over the traditionally used cryoprotectants such as sorbitol as it does not add any unwanted sweet flavors. Litesse and Litesse II are second and third generation polydextroses with a reduced titratable acidity and improved flavor compared to polydextrose (Table 11.2). Litesse II was specifically developed for use in light foods that are more flavor sensitive and where

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Figure 11.6 Freezing point depressions of Litesse, selected sugars, and sorbitol at various concentrations. (Courtesy of Pfizer Ltd., Kent, United Kingdom.)

a higher level of sugar and fat replacement is required, e.g., confectionery, chocolate, bakery fillings and toppings, jams/jellies, syrups, and spreads. The sensory characteristics of Litesse and Litesse II in aqueous solution were similar when judged by trained panelists using Quantitative Descriptive Analysis, and there were no significant differences between the two at equivalent concentration in aqueous solution. However, sweetness was the most intense flavor characteristic and Litesse II was judged sweeter than Litesse at a concentration of 20%. The sweetness of Litesse II was probably enhanced by its lower titratable acidity. Litesse II was also less bitter, astringent, and oily than Litesse. Since Litesse II has a tenfold lower titratable acidity compared to Litesse, products made with the former rarely have to be buffered. The acidity of Litesse II also means that sucrose inversion in the presence of Litesse II is negligible and there is minimal effect on fat rancidity and subsequent flavor changes. In practical terms, this means that in most applications there is no need for an additional neutralization step when using Litesse. Litesse II can be used at greater levels in a formulation because of its clean, mildly sweet taste. In all other respects Litesse and Litesse II have the same bulking and functional properties as the original polydextrose.

Table 11.2 Comparison of Some Characteristics of Polydextrose, Litesse and Litesse II Property

Polydextrose

Litesse

Litesse II

Taste Acidity (mequiv/g) Usage levels

Tart, acidic 0.1 Low <5% Strong High Yes

Bland, neutral 0.03 Medium 5–10% Manageable Modest Sometimes

Clean, mildly sweet 0.003 High 10% Negligible Minimal Rarely

Extent of sugar inversion Extent of fat rancidity Neutralization required

Courtest of Pfizer Ltd., Kent, United Kingdom.

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Granulated forms of Litesse are also available for ease of handling and speed of dissolution. The primary applications for granulated Litesse are in the beverage, confectionery, and frozen dairy segments. Granulated Litesse has been shown to dissolve in water (80 g/100 g water, 23°C, 270 rpm) in 4.5 min compared with similar quantities of generic polydextrose and Litesse which took 9.3 and 12.2 min to dissolve, respectively. The flavor quality of the new generation polydextroses, Litesse and Litesse II, is such that these bulking agents can successfully replace sugar and some fats in food products without any adverse reaction on the taste quality of the final product. Since the polydextroses are essentially bland-tasting, they can be used in both sweet and savory applications. To maintain the sweetness level in sweet products such as confectionery, it is advisable to replace the sweetness by the use of an approved high intensity sweetener. The new generation sweeteners such as aspartame, acesulfame-K and alitame can be used with polydextrose.

11.5 APPLICATIONS Polydextrose is most commonly used to replace sugars in various desserts, confections, baked goods, and other sweet foods. Typical applications for polydextrose include: ice cream, instant puddings, jams, jellies, pastry, chilled desserts, bakery fillings, cakes, biscuits, confections, frozen desserts, toppings and frostings, instant drinks, cereal bars, extruded snacks, sauces, salad dressings, and peanut spreads. In these applications, polydextrose reduces calories while maintaining the body and texture of full-sugar foods. Although polydextrose is not a fat-replacer per se, it has a relatively high viscosity in solution and can therefore contribute to the mouthfeel and creaminess of fat-reduced formulations. Polydextrose can therefore be considered as a fat-mimetic in some applications. 11.5.1 REDUCED-FAT PASTRY Polydextrose can be used to make fat-reduced pastry. In shortcrust pastry, the fat content can be reduced by up to 50% with the addition of polydextrose while maintaining the texture normally associated with traditional full-fat pastry. Studies have shown that the addition of polydextrose to shortcrust pastry increased the crispness (especially noticeable in oven-reheated pastry products); reduced pastry shrinkage; improved the machinability of very thin sheets of dough; caused browning under microwave reheat conditions; and reduced the amount of sugars and fats in shortcrust pastry without affecting the organoleptic quality of the product. All of these benefits were possible without any changes in processing conditions. The effect of adding polydextrose to fat-reduced pastry dough in apple pies has been studied. Polydextrose was added to the short-crust pastry dough at a rate of 13% on a flour weight basis as shown in Table 11.3. The flour, fat, and sodium metabisulphite were placed into the bowl of a planetary style mixer fitted with a pastry knife and mixed on slow speed for 2 min. The salt, sugar, or polydextrose were dissolved in the water and added to the flour and fat over a period of 10 s on slow speed. The mixture was then mixed on medium speed for 45 s. The dough was left to stand for 30 min. For the apple filling, the glycerine was dispersed with water before blending with the other ingredients. Subsequently, 45 g of paste was blocked into 11 cm foil trays and filled with 60 g of apple pie filling. The paste was also sheeted to 2.5 mm and lids cut at 11.3 cm diameter. A steam vent was cut into each lid before they were blocked onto the base of the pie. The pies were baked for 20 min in a gas fired reel oven, cooled, and stored in cellulose film at 20°C.

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Table 11.3 The Use of Polydextrose in a Reduced-Fat (38%) Pastry for Apple Pie Ingredients

% Flour weight For the pastry:

White pastry flour White shortening or vegetable oil Salt Water Sodium metabisulphite (SMS) Polydextrose or sucrose Ingredients

100 38 (Fat reduced from 47%) 1.2 19 0.0223 13 % Apple weight

For the apple filling: Canned chopped apples Sucrose Salt Water Pregelatinized waxy maize starch Glycerine

100 100 1 23 10 12

Courtesy of Pfizer Ltd., Kent, United Kingdom.

After baking, the pies made from fat-reduced pastry containing polydextrose were slightly darker than products made from a control pastry without polydextrose. Both the lid and base pastry were darker in the polydextrose-containing samples. The brown color development may be due to Maillard reaction or even the polydextrose itself. The polydextrose pies were approximately 10% larger than the control samples. Since polydextrose reduces pastry shrinkage, thinner sheets of dough may be machined (<2.5mm) and baked. Polydextrose has been evaluated in savory and sweet, fat-reduced, shortcrust pastry and found to give satisfactory products in all respects. Polydextrose produced a slightly more crumbly, “short” texture when used as a substitute for sucrose or as a partial fat replacer. In thin dough sheets, the baked product remained crisp yet friable. Using polydextrose, the fat content of shortcrust pastry can be reduced to as little as 13 to 15% of dough weight while maintaining acceptable sensory characteristics. The addition of small amounts of other shortening agents such as cornflour and rehydrated potato flakes may improve the rework properties of the doughs at very low fat levels. In general, the use of polydextrose at levels between 5 to 8% dough weight are optimal. In studies sponsored by Pfizer Inc., light and electron microscopy methods have been used to examine the structures of raw and cooked samples of pastry containing polydextrose. In addition, the effects of polydextrose on the hydration of the individual flour components have been assessed using simple model systems (Groves et al., 1990). Stereolight microscopy of fractured pieces of pastry showed a difference in crumb structure between pastry containing polydextrose and the control sample. The control sample had a more solid and continuous structure whereas addition of polydextrose produced a coarser structure with an increased layering effect. The surfaces of the polydextrose pastry were also darker. Cold-stage Scanning Electron Microscopy (Cryo-SEM), was also used to examine the polydextrose pastry (Groves et al., 1990). The surface of the cooked control sample

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was smoother and more continuous than that of the samples containing 10% (dough weight) polydextrose. Figures 11.7 and 11.8 demonstrate the differences between the samples. The outlines of the starch grains could be seen more clearly in the pastry with polydextrose, and larger spaces or cracks were visible (Figure 11.8). Raw pastry samples were also examined using a resin-embedding technique and light microscopy (Groves et al., 1990). In the control samples, more protein was dispersed to form an even, continuous network linking the dark, oval-shaped starch grains. By contrast, in the polydextrose pastry, the protein was not as well-dispersed resulting in a coarser, less homogeneous structure than in the control samples (Figure 11.8). The effects of polydextrose were seen at levels of addition as low as 2.5% (dough weight basis), but were most marked at the 10% level. To gain further information on the effect of polydextrose on water absorption in pastry, model systems were prepared using a gluten wash method (Groves et al., 1990). In these models, 12 g of gluten, wheat starch, or flour were mixed with 18 g of water or 18 g of water and 2 g of polydextrose and the free water was assessed visually. The observations showed that there was more free water present in the model containing gluten, water, and polydextrose than in the model containing gluten and water only, suggesting that polydextrose was interfering with water uptake by the gluten. Little difference in water uptake was found in the starch- and flour-based models. Both the gluten and flour model systems described above were examined using coldstage SEM (Groves et al., 1990). The samples were etched to sublime away some of the water, leaving a lacy network structure where less bound water was present. Comparison of the model systems showed that addition of polydextrose resulted in a more icy matrix (Figure 11.9). This indicated reduced hydration of the gluten in the presence of polydextrose. When flour and water are mixed together, the gluten proteins hydrate, uncoil, and form a three dimensional visco-elastic structure of large proteins primarily linked together by disulphide bonds. In order to make shortcrust pastry, the fat in the recipe acts as the “shortening” agent, interrupting and preventing continuous gluten development (Patient, 1994). It has been proposed that in fat-reduced pastry containing polydextrose, “shortening” action is achieved by three mechanisms. First, polydextrose absorption of water reduces the amount of water available to the gluten and starch; second, polydextrose reduces the pH of the system, thereby inhibiting formation of gluten; and third, polydextrose binds to the protein. The microscopy and model system studies have indicated that polydextrose inhibited the rapid development of strands of gluten when wheatflour endosperm came into contact with water. It is therefore likely that the first mechanism predominates, although the second and third mechanisms cannot be ruled out. 11.5.2 OTHER APPLICATIONS Polydextrose can be used to replace part of the fat in soft chewy candies with little effect on structure. Since polydextrose has a higher viscosity than simple sugars and polyols at equivalent concentrations, it can contribute to the creamy mouthfeel of the product. Spoonable and pourable dressings can be made with reduced levels of oil using polydextrose. Polydextrose provides some of the functionality of the oil by providing mouthfeel, viscosity, and bulk in this application (Kappas et al., 1993). Polydextrose functions particulary well as a sugar replacer and fat mimetic in chilled desserts. A dessert can readily be formulated with polydextrose to achieve a 50% calorie reduction when used with a high intensity sweetener. Layered desserts and yogurts (Barrantes and Tamime, 1993) have been successfully formulated using polydextrose as a low-calorie bulking agent.

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a

b Figure 11.7 Cold-stage scanning electron micrograph of the surface of cooked control pastry (a) and cooked pastry containing 10% (dough weight) polydextrose (b). (Courtesy of Leatherhead Food R. A., Surrey and Pfizer Ltd., Kent, United Kingdom.)

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a

b Figure 11.8 Light micrograph of a resin section of raw control pastry (a) and raw pastry containing 10% (dough weight) polydextrose (b). (Courtesy of Leatherhead Food R. A., Surrey and Pfizer Ltd., Kent, United Kingdom.)

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a

b Figure 11.9 Cold-stage scanning electron micrograph of the control flour and water model system (a) and of the flour and water model system containing polydextrose (b). (Courtesy of Leatherhead Food R. A., Surrey and Pfizer Ltd., Kent, United Kingdom.)

Polydextrose can be used as a low-calorie bulking agent and texture modifier in the water phase of a variety of emulsion products that can be considered “spreads.” A 33% calorie and fat reduction is possible in products such as peanut spread (FAP, 1988; Pfizer, 1989).

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11.6 NUTRITIONAL AND TOXICOLOGICAL ASPECTS Numerous studies in animals and man have shown that polydextrose shares many metabolic characteristics with other naturally occurring or synthetic low-digestible nonstarch polysaccharides. In particular, it was found that only a small fraction of polydextrose can be hydrolyzed by digestive glycolytic enzymes (White et al., 1988; Kruger et al., 1990; Kobayashi and Yoshino, 1989) and that a certain amount of the undigested and thus unabsorbed material is fermented by the intestinal microflora (Kruger et al., 1987). Furthermore, it has been shown that a substantial amount of ingested polydextrose can neither be digested nor fermented and is thus excreted in feces (Figdor and Rennhard, 1981; Figdor and Bianchine, 1982; McGaw, 1991; Achour et al., 1992). It follows from these metabolic features that polydextrose is only incompletely metabolized and that it has therefore a reduced physiological energy value. The results of numerous metabolic disposition studies on polydextrose in animals and man indicate that for the purpose of nutrition labeling, a physiological energy value of 1 kcal/g may be attributed to this polymeric compound. This value is supported by the results of three recently completed studies in germ-free and conventional rats as well as in healthy human volunteers (Juhr and Franke, 1992; McGaw, 1991; Achour et al., 1992) and by a meta-analysis of the data from these three studies and all earlier studies using a consistent approach based on determination of digestibility, fermentability and energy salvage. Polydextrose is well tolerated in amounts likely to be consumed. Studies by Pfizer, Inc., have shown that a single dose of 50g is unlikely to cause gastrointestinal effects except in particularly sensitive persons. In a study in which participants received up to 130g/day, the mean laxative threshold dose was 90g/day. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the EC Scientific Committee for Food (SCF) have awarded polydextrose an Acceptable Daily Intake (ADI) “not specified” in February 1987 (FAO/WHO, 1987) and 1990 (Commission EC Report, 1990), respectively. An examination of the available data indicates that gastrointestinal tolerance to polydextrose is better than to polyols (Grossklaus, 1990). This is not surprising in view of the fact that polydextrose is osmotically less active (higher molecular weight), and that only half of an ingested dose is fermented in the colon. Oral tolerance tests with 50 g of glucose, starch and polydextrose, respectively, were performed in noninsulin dependent diabetics. After glucose administration, the increase in capillary blood glucose and serum insulin concentration were significantly higher than after starch and polydextrose intake. Therefore, polydextrose can be used as a dietetic susbstitute for diabetics (Bachman et al., 1982). Tests have shown that polydextrose has a very low potential for promoting dental caries. These results have been confirmed in a number of in vitro, in vivo, and pH telemetric studies. The Swiss government allows a “ Safe For Teeth” labeling for polydextrose on the basis of studies carried out by Muhlemann (1980). Polydextrose is recognized as a valuable source of fiber in Japan and in a growing number of other countries. Japanese regulations allow polydextrose to be used as a source of soluble fiber in many beverages and other products (Hamanaka, 1987). The Japanese definition of dietary fiber includes “polysaccharides, related polymers, and lignin, which are resistant to hydrolysis by the digestive enzymes of man” (The Foundation for Health and Physical Development, Japan, 1990). Applications for the use of polydextrose as a source of fiber are pending in a number of countries.

11.7 LEGISLATIVE AND LABELING STATUS Following The Scientific Committee for Foods (SCF) safety evaluation, polydextrose was included in the EC positive lists of additives and is now included in the Council ©1996 CRC Press LLC

Directive on Food Additives other than Colors and Sweeteners (95/2/EC) in Annex 1 (generally permitted food additives at quantum satis levels), and Annex V (carriers and carrier solvents). Polydextrose is listed as E1200 in Europe and is currently approved in over 45 countries. In the U.S., polydextrose is approved by the Food and Drug Administration (FDA) for use in the following product categories: chewing gum, confections and frostings, dressings for salads, frozen dairy desserts and mixes, gelatins, puddings and fillings, hard candy, soft candy, baked goods and baking mixes, fruit spread, peanut spreads, toppings, and sweet sauces. The FDA also allows labeling of a caloric value of 1 kcal/g for polydextrose, as do most countries where polydextrose is approved.

REFERENCES Achour, L., Flourie, B., Briet, F., Pellier, P., Martealp, Ph., and Rambaud, J.C., Gastrointestinal effects and energy value of Polydextrose in normal man, Unpublished report of INSERM, Paris, 1992. Allingham, R.P., Polydextrose-a new food ingredient, in Technical Aspects, Chemistry of Foods and Beverages: Recent Developments, Academic Press, New York, 1982, 293. Bachmann, W., Haslbeck, M., and Mehnert, H., Untersuchungen zur diatetischen Vewendung von Polydextrose bei Diabetikern., Akt. Endokr. Stoffw., 3, 124, 1982. Baer, R.J. and Baldwin, K. A., Freezing points of bulking agents used in manufacture of low-calorie frozen desserts, J. Dairy Sci., 67, 2860, 1984. Baer, R.J. and Baldwin, K.A., Bulking agents can alter freezing, Dairy Field, February, 1985. Barrantes, E. and Tamime, A.Y., Fat-free yogurt-like or dislike, Ingredients Focus, November, 1993. Beereboom, J.J., Technical aspects of polydextrose, Polydextrose Trade Press Briefing, New York, May 28, 1981. Commission of the European Communities Report of the 71st Meeting of the EC-Scientific Committee for Food., Brussels, January 25/26, 1990. FAP. (7A3998), Use of Polydextrose in peanut butter spread, Fed. Register 53, (16), January 26, 1988. Figdor, S.K. and Rennhard, H.H., Caloric utilization and disposition of 14C polydextrose in the rat., J. Agric. Food Chem., 29, 1181, 1981. Figdor, S.K. and Bianchine, J.R., Caloric utilization and disposition of 14C polydextrose in man., J. Agric. Food Chem., 31, 389, 1983. Grossklaus R., Gesundheitliche Bewertung der Risiken durch Lebensmittelzusatzstoffe am Beispiel der Zuckeraustauschstoffe., Bundesgesundheitsblatt, 12, 578, 1990. Groves, K., Foster, T., Buchanan, M., and O’Sullivan, M., “ An Examination of the Effects of Polydextrose Addition on the Texture and Structure of Pastry.” A confidential report P3125 for Pfizer, Inc., Leatherhead Food Res. Assoc., Surrey, U.K. May, 1990. Hamanaka. M, Polydextrose as a water-soluble food fibre, Food Ind., 30(17), 73, 1987. Joint FAO/WHO Expert Committee on Food Additives, Evaluation of certain food additives and contaminants, Thirty-first report of the Joint FAO/WHO Expert Committee on Food Additives, World Health Organization Technical Report Series 759, 31, 1987. Kappas, J.D., Kopchik, F.M., and Moppett, F.K., Litesse®, in Science for the Food Industry of the 21st Century, Biotechnology, Supercritical Fluids, Membranes and other Advanced Technologies for Low Calorie, Healthy Food Alternatives, Manssur Yalpani, Ed., ATL Press, Mount Prospect, IL, 1(3), 1993. Kruger, D., Grossklaus, R., Wesolowski, T., and Beier, M., Microcalorimetric investigations into the metabolic activity of rat caecal flora in the presence of different sugars and sugar substitutes, Microbios, 57, 42, 1987. Kruger, D., Ziese, T., and Grossklaus, R., Caloric availability of Polydextrose in rats., Akt. Ernahr.- Med., 15, 82, 1990. Kobayashi T. and Yoshino H., Enzymatic hydrolysis of Polydextrose, Denpun Kagaku, 36, 283, 1989.

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McGaw, B.A., The development of a method to measure the caloric availability of bulking agents., Unpublished report of the Rowett Research Institute, Aberdeen, 1991. Muhlemann, H.R., Polydextrose-ein kalorienarmer Zuckererstzstoffe. Swiss Dent., 1(3), 29, 1980. Murray, P.R., Polydextrose, in Low-Calorie Products, Birch, G.G. and Lindley, M.G., Eds., Elsevier Applied Science, London, 1988, 83. Moppett, F.K., Polydextrose, in Alternative Sweeteners 2nd ed., O’Brien Nabors, L. and Gelardi, R.C., Eds., Marcel Dekker, New York, 1991, 401. Park, J.W., Effects of cryoprotectants on properties of beef protein during frozen storage, Ph.D. Dissertation, North Carolina State University, Raleigh, 1986. Park, J.W. and Lanier, T.C., Combined effects of phosphates and sugar and polyols on stabilization of fish myofibrils., J. Food Sci., 52(6), 1509, 1987. Patient, D., The chemistry of pastry products, Nutr. Food Sci., 4, 33, 1994. Pfizer, Inc., Polydextrose in Peanut Butter, U.S. Patent 4,814,195, 1989. Rennhard, H.H. (Pfizer), U.S. Patent 3,876,794, 1975. The Foundation for Health and Physical Development, Ministry of Health and Welfare, Tokyo, Japan. Thomas, J.W., Brown, D.L., Hoch, D.J., Leary, J.J., and Dokladalova, J., Determination of polydextrose (polymer) and residual monomers in polydextrose by liquid chromatography, J. Assoc. Off. Anal. Chem., 74(3), 571, 1991. White, J.S., Parsons, C.M., and Baker, D.H., An in vitro digestibility assay for the prediction of the metabolizable energy of low-calorie dextrose polymeric bulking agents., J. Food Sci., 53, 1204, 1988.

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Chapter

13

Low-Calorie Fats and Synthetic Fat Substitutes Barry G. Swanson CONTENTS 13.1. Introduction 13.2. Structured Lipids/Low-Calorie Fats 13.3. Carbohydrate Fatty Acid Polyesters 13.4. Other Synthetic Fat Substitutes 13.5. Conclusions References

13.1 INTRODUCTION Fats and oils contribute flavor, palatability, mouthfeel, creaminess, and lubricating action to foods (Swanson and Akoh, 1994). Frying in fats or oils transmits heat rapidly and uniformly, evaporates moisture, and provides a high temperature, promoting crisping and browning. The desirable contribution and functions that fat provides in foods are important to consumer expectations, desires, and acceptance of fat-containing foods. The basic approach for achieving calorie reduction while maintaining the chemical structure of the triacylglycerol is by manipulation of the composition of the fatty acids esterified to the glycerol. This type of compound therefore constitutes a separate group of fat replacers, i.e., the low-calorie fats. Since replacement of the fatty acids of triglycerides with alternative acids is usually achieved through structuring of triglycerides by hydrolysis and random transesterification of medium-chain triglycerides (MCTs) and long-chain triglycerides (LCTs), such compounds are commonly referred to as structured lipids. Synthetic fat substitutes are compounds that physically and chemically resemble triglycerides, are stable to cooking or frying temperatures, and theoretically replace fat on a one to one, gram for gram basis in foods (Rudolph et al., 1991). Fat substitution ©1996 CRC Press LLC

conceptually is the reduction in fat-contributed calories from a food by substituting a fat-like substance in the food that is neither hydrolyzed nor absorbed like triglycerides, contributing less calories than fat (Hamm, 1984). Recognized strategies for developing a poorly or nondigested, and poorly or nonabsorbed fat-like substance are to reengineer, redesign, chemically alter, synthesize, or structure conventional triglyceride components of fats and oils to retain conventional functional properties in foods while reducing or removing susceptibility to hydrolysis and/or absorption in the intestine. Suggested design strategies for fat substitutes include (Hamm, 1984; Mascioli et al., 1988; Matthews and Kennedy, 1990; Singh et al., 1991; Swanson and Akoh, 1994): 1. Replacement of the glycerol moiety of triglycerides with alternative polyols or sugars 2. Reversal of the ester linkage of fatty acids to glycerol 3. Reduction of the ester linkage of the glycerol moiety to an ether linkage

Another approach to develop or discover reduced-calorie fat substitutes is to explore compounds with functional and physical properties similar to fats or oils, but with a chemical structure unrelated to triglycerides. Two examples suggested by Hamm (1984) are nonabsorbable polymeric phenyl methyl siloxane or silicon oils, and microcapsules to replace dispersed oil droplets in emulsified foods.

13.2 STRUCTURED LIPIDS/LOW-CALORIE FATS A structured lipid is a triglyceride obtained by the hydrolysis and random transesterification of medium-chain triglycerides (MCTs) and long-chain triglycerides (LCTs) (Mascioli et al., 1988; Matthews and Kennedy, 1990). The fatty acids of MCTs are of carbon chain length twelve and less, while the fatty acids of LCTs are of carbon chain length greater than twelve (Matthews and Kennedy, 1990). More recently, structured lipids have also been prepared with short-chain fatty acids (acetic, propionic, and/or butyric) and long-chain fatty acids (predominantly stearic) esterified to the glycerol backbone (Smith et al., 1994). Structured lipids provide the physical and functional properties of fat while contributing approximately one half of the calories of the normal edible oil (Matthews and Kennedy, 1990; Smith et al., 1994). Short- and medium-chain fatty acids are hydrolyzed from triglycerides, quickly absorbed, and transported via the portal vein to the liver for oxidation and energy production. Long-chain fatty acids are hydrolyzed from triglycerides, absorbed through the intestinal wall, reesterified to triglycerides, and packaged with protein and phospholipids to form chylomicrons. Chylomicrons enter the lymphatic system and later the circulatory system for distribution to cells. Thus, short- and medium-chain fatty acids bypass the lymphatic system and are more readily used for caloric energy than longchain fatty acids, and have a low tendency to be incorporated into tissue lipids to form depot fat. Short-chain fatty acids provide fewer calories per unit weight than long-chain fatty acids. In contrast to short-chain fatty acids, long-chain fatty acids are poorly digested and absorbed (Finley et al., 1994; Hayes et al., 1994; Matthews and Kennedy, 1990; Smith et al., 1994). Structured triglycerides are created by chemically catalyzed transesterification or interesterification of hydrogenated vegetable oils with triacylaglycerols of short- or medium-chain fatty acids (Klemann et al., 1994). The resulting triglycerides contain fatty acid distributions representative of the initial triglycerides, with the short-, medium-, and long-chain fatty acids randomly distributed on the glycerol backbone (Klemann et al.,

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1994; Smith et al., 1994). Selection of triglycerides containing specific short-, medium-, and/or long-chain fatty acids for the initial reaction mixture allows for control of the functional and physical properties of the resulting fats or oils. Caprenin was the first structured lipid introduced on the market as a medium- and long-chain low-calorie triglyceride by the Procter & Gamble Company. Caprenin is a synthetic triglyceride composed of caprylic (C8:0), capric (C10:0), and behenic (C22:0) fatty acids. The medium-chain triglycerides are derived from coconut and palm kernel oils, while the behenic acid comes from hydrogenated canola oil. Because the long-chain behenic acid liberated in gastric hydrolysis is mostly transported through the intestinal tract unmetabolized, and because the remaining caprylic and capric fatty acids are metabolized less efficiently than more common fatty acids, Caprenin provides a caloric density of 5 kcal/g. Caprenin is approved for use as a confectionery fat, apparently because the fatty acids in Caprenin occur naturally in other foods. Minor concerns remain in relation to the limited knowledge surrounding the metabolism of behenic acid. Caprenin was designed to mimic the physical properties of cocoa butter or confectionery fat, and is being used in conjunction with polydextrose (Pfizer Specialty Chemicals Group) in Milky Way II and Milky Way Lite (Mars, Inc.) candy bars. The potential utility of Caprenin as a frying fat is limited by thermal stability and price. A more recent family of structured triacylglycerols named Salatrim was discovered by the Nabisco Foods Group (Smith et al., 1994; Softly et al., 1994). Salatrim is composed of a random distribution of short-chain fatty acids (acetic, propionic, and/or butyric) and long-chain fatty acids (predominantly stearic). The caloric availability of Salatrim is approximately 5 kcal/g. The melting temperature range of Salatrim is controlled by incorporation of various preparations of short-chain fatty acids on the triacylglycerol with the long-chain saturated fatty acids. The ratio of short-chain fatty acids to long-chain fatty acids is used to obtain flexibility in the functional and physical properties of Salatrim. Salatrim preparations are available to emulate cocoa butter, as well as for use in baked products and filled dairy products. An extensive testing program of the chemistry, genetics, toxicology, animal feeding outcomes, and human clinical trials concluded that consumption of anticipated concentrations of Salatrim resulted in no significant adverse biological, toxicological, or nutritional effects (Hayes and Riccio, 1994; Hayes et al., 1994a, b, c; Smith et al., 1994). In 1994, it was announced that Pfizer’s Food Science Group had licensed the Salatrim family of reduced-calorie fats from Nabisco and was planning to develop and commercialize Salatrim for enrobed and molded chocolates, ice cream, dairy products, snacks, and baked products (Venardos, 1995). Jojoba oil, although not a synthetic or structured triglyceride, is interesting in the context of this chapter because it contributes less than 4 kcal/g to foods due to the presence of C20:1 and C22:1 fatty acids leading to poor digestibility (Hamm, 1984). The viscosity and interfacial tension of jojoba oil are similar to other types of edible oils. Jojoba oil is only slightly hydrolyzed in vitro, suggesting possible resistance to digestion in vivo. (Artz and Hansen, 1994; Hamm, 1984; Ranhotra and Gelroth, 1989). Since the majority of jojoba oil is not absorbed, potential problems with anal leakage, diarrhea, reduced growth, nutrient absorption, and death may result from excessive consumption (Decombaz et al., 1984; Ranhotra and Gelroth, 1989). Jojoba oil and its derivatives are being used in a variety of nonfood applications including cosmetic and pharmaceutical products (Hamm, 1984; Winsniak, 1994).The potential for jojoba oil as a low-calorie oil substitute may be limited due to its cost and limited availability (Artz and Hansen, 1994; Ranhotra and Gelroth, 1989).

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13.3 CARBOHYDRATE FATTY ACID POLYESTERS The development of carbohydrate-based and alkyl glycoside-based fatty acid polyesters as fat substitutes to replace edible fats and oils on a one-to-one basis in food is described in detail by Akoh and Swanson (Akoh, 1994; Akoh and Swanson, 1987a and b, 1989a and b, 1990, 1994). Carbohydrate and alkyl glycoside fatty acid polyesters exhibit functional and physical properties resembling conventional triglycerides without contributing significantly to the caloric content of the diet. Digestion and absorption are reduced by saturating a carbohydrate, sugar alcohol, or an alkyl glycoside with fatty acids esterified to the available hydroxyl groups. Utilizing the wide variety of fatty acids and carbohydrate moieties naturally available, carbohydrate and alkyl glycoside fatty acid polyesters can be synthesized to incorporate desirable physical and functional properties. The carbohydrate fatty acid polyesters are macroingredients substituted for fats and oils in foods to incorporate desirable functional properties including frying, while reducing the caloric contribution of fats and oils. The most often studied and only noncaloric synthetic fat substitute that is being reviewed for FDA approval is olestra produced by The Procter & Gamble Company. Olestra is a patented and registered trademark name for “the mixture of the octa-, hepta-, and hexaesters formed from the sugar, sucrose, and the long-chain fatty acids isolated from vegetable oils” (Jandacek, 1991). Sucrose fatty acid polyesters (SPE), more accurately called sugar, polyol, carbohydrate, or saccharide fatty acid esters, are defined in the patent literature as the hexa-, hepta-, and octaesters of polyols such as methyl glucose, sucrose, raffinose, mannitol, or sorbitol with saturated or unsaturated fatty acids (Hass, 1968). The nomenclature chosen, carbohydrate polyesters, is not chemically accurate. The carbohydrate or polyol moiety is not a chain of sugars, nor are the fatty acids or esterified fatty acids chains that resemble fibers, plastics, or cloth recognized as polyesters. Carbohydrate fatty acid polyesters are a synthesized chemical compound with one to four, eight, eleven or more fatty acids esterified to the hydroxyl groups of polyol carbohydrates such as methyl glucose, sucrose, raffinose, or maltodextrins. Carbohydrate fatty acid polyesters are lipophilic, nondigestible, nonabsorbable fatlike molecules with physical and chemical properties of conventional fats and oils (Akoh, 1994; Toma et al., 1988). Carbohydrate fatty acid polyesters are generally synthesized by one of four methods: (1) transesterification of the saccharide with methyl, ethyl, or glycerol fatty acid esters; (2) acylation with fatty acid anhydrides; (3) acylation with fatty acid chlorides; or (4) acylation with fatty acids per se (McCoy et al., 1989). A solvent-free, two-stage synthesis of sucrose fatty acid polyesters avoiding the use of toxic solvents is reported by Rizzi and Taylor (1976 and 1978). In the first stage, a 3:1 mole ratio of fatty acid methyl ester and sucrose is reacted in the presence of potassium soaps forming a homogeneous melt containing predominantly the smaller fatty acid methyl esters of sucrose. In the second stage, additional fatty acid methyl esters are attached to produce saturated sucrose fatty acid polyesters in yields up to 90% based on sucrose at temperatures of 130 to 150°C. In both stages, the sucrate ion generated with alkali metal hydrides or Na-K alloys catalyze sucrose ester synthesis. Modifications of the solvent-free two-stage synthesis by Hamm (1984) include adding methyl oleate at the beginning of the reaction, and adding sucrose and sodium hydrides in increments during the synthesis reaction. As reaction temperatures and times increase, the color of the reaction mixtures becomes darker and more difficult to clean up. Approximately 80 to 90% yields of sucrose polyester are achieved by reacting sucrose octaacetate with methyl palmitate in the presence of sodium or potassium metal at 110 to 120°C for up to 6 h (Mieth et al., 1983). Yamamoto and Kinami (1986) reported that an admixture of

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sucrose mono- and di-esters of oleate, molten sucrose, and methyl oleate, a basic catalyst (1 to 10%) such as sodium, and potassium carbonate or hydroxide to form a homogeneous melt at 120 to 180°C under less than 10 mm Hg pressure, yielded 95 to 99% sucrose fatty acid polyester. A solvent-free single step synthesis combines the sugar, acetate, fatty acid methyl esters (FAME) and 1 to 2% sodium metal in a three-neck reaction flask prior to heating (Akoh and Swanson, 1990; McCoy et al., 1989). Formation of a one phase melt is achieved 20 to 30 min after heat is applied (Akoh and Swanson, 1990). High yields of sucrose fatty acid polyesters (SPE) are obtained at temperatures as low as 105°C, and synthesis times as short as 2 h by utilizing a vacuum of less than 5 mm Hg pressure (McCoy et al., 1989). The advantage of the solvent-free single step synthesis is that acetate groups in the sucrose octaacetate are good leaving and protecting groups against sucrose degradation and carmelization during SPE synthesis; thus the yield of SPE is increased and isolation and recovery of SPE are more convenient (Akoh and Swnason, 1988; McCoy et al., 1989; Mieth et al., 1983). Modification of syntheses by selecting catalysts such as potassium hydroxide, potassium carbonate, and/or sodium methoxide results in improved yields and more efficient clean-up procedures (Akoh and Swanson, 1988; Drake et al., 1994; Feuge et al., 1970; McCoy et al., 1989; Myhre, 1971; Yamamoto and Kinami, 1986). The success of oligosaccharide fatty acid polyester syntheses has led to interest in the possibility of synthesizing even larger polysaccharide esters such as those based on maltodextrins (Akoh, 1994; Akoh and Swanson, 1987a, 1989a and b). Direct esterification of reducing sugars such as glucose and galactose results in extensive sugar degradation and charring. Therefore, glycosylation or alkylation is necessary to convert reducing sugars with reactive C-1 anomeric centers to nonreducing less reactive anomeric centers (Akoh, 1994; Akoh and Swanson, 1989a). Synthesis of alkyl glucoside fatty acid mono- and di-esters for use as emulsifiers (Albano-Garcia et al., 1980; Gibbons and Swanson, 1959), antimicrobials (Yang, 1993), or additives to culinary mixes (Myhre, 1971) is reported. However, little is reported on the synthesis of alkyl glycoside fatty acid polyesters for use as fat substitutes to replace edible fats and oils in foods. Myhre (1971) describes a two-stage process for synthesis of methyl glucoside tetrapalmitate utilizing sodium methoxide as a catalyst and methyl glucoside mono-, di-, tri- and tetra-propionates as intermediates for interesterification with methyl palmitate. Akoh and Swanson (1989a) reported synthesis of novel alkyl glycoside polyesters by solvent-free interesterification of the alkyl glycoside tetraacetate with fatty acid methyl esters of long chain fatty acids from vegetable oils. The potential utilization of methyl glucoside fatty acid tetraesters as noncaloric fat substitutes is under investigation. In recent years, the increased availability and reduction in price of specific lipases have meant that the preparation of carbohydrate fatty acid polyesters by enzymic interesterification is an increasingly attractive proposition (Bjorkling et al., 1989; Riva, 1994; Seino et al., 1984). Enzymic syntheses offer the advantage of specificity, low reaction temperatures, reasonable yields, and less purification technology compared to chemical syntheses. For example, clean-up and purification of chemically synthesized carbohydrate fatty acid polyesters involves a variety of procedures including washing extensively (four to five times) with 10 to 20 volumes of water at 70°C; washing five times with 95% ethanol at 80°C; clay washing with 5% by weight of bleaching clay; short path distillation; and finally steam distillation. The fatty acids selected as starting materials for the synthesis of sucrose fatty acid polyesters contribute to the functional properties of the synthetic fat substitute including the melting point onset and temperature, consistency, color, heat stability, and others.

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The physical properties of carbohydrate fatty acid polyesters are reported by Akoh and Swanson (1989a and b, 1990), Jandacek and Webb (1978) and Drake and colleagues (1994a, b, and c). In general, the color, consistency, density, specific gravity, and refractive indices of the carbohydrate fatty acid polyesters approximate the physical properties of the natural vegetable oils and animal fats used in their preparation (Akoh, 1994). However, the melting point onset, hardness, and fatty acid profiles of milkfat blend polyesters are different than those of milkfat, and are dependent on the fatty acid composition of the sucrose fatty acid polyesters (Drake et al., 1994a). The viscosities of milkfat SPE and milkfat-blend SPE are significantly greater than the viscosity of milkfat (Drake et al., 1994c). The rheological behavior defining the viscoelastic behavior of milkfat SPE as storage (G′ ) and loss (G″ ) moduli are frequency dependent whereas those for milkfat are not. Milkfat is more elastic than milkfat SPE at 20°C as determined by a smaller loss tangent, the ratio of loss modulus to storage modulus. Practical applications of sucrose fatty acid polyesters in foods such as ice cream (Wei, 1984), Cheddar cheese (Drake et al., 1994a), sausage (Linares, 1995), and as a vegetable oil ingredient or frying fat suggest great potential for promoting improved consumer health as well as achieving functional and economical acceptance and success. For a detailed discussion of some of the nutritional implications of replacing part of the fat in the diet by SPE, the reader is referred to Chapter 2.

13.4 OTHER SYNTHETIC FAT SUBSTITUTES Many partially and poorly digested organic compounds are being investigated as potential fat substitutes and these are discussed in a comprehensive review by Artz and Hansen (1994). Since none of these are allowed for use in foods to date, the range of compounds is discussed only very briefly in the section below. Esterification of (poly-) pentaerythritol and other polyhydric alcohols with selected fatty acids produces noncaloric, nondigestible, heat resistant organic compounds that retain the functional attributes of fats or oils. Alcohols with the neopentyl nucleus (–(CH2)4C), pentaerythritol, trimethyloethane, trimethylol-propane, trimethylolbutane, and neopentylalcohol, can be esterified with fatty acids to produce potentially acceptable fat substitutes (Artz and Hansen, 1994; Barth et al., 1944; Minich, 1950). Polyvinyl alcohol (PPVA) fatty acid esters have been suggested for use as fat substitutes (D’Amelia and Jacklin, 1990). The polyvinyl alcohol fatty acid esters can be synthesized by direct esterification of low MW polyvinyl alcohol with excess fatty acids, chlorides or anhydrides; interesterification of polyvinyl acetate with fatty acid methyl esters; or transesterification of polyvinyl alcohol with an excess of unsaturated fatty acid esters. Trialkoxytricarballylate (TATCA) (Best Foods Division of CPC International Inc., Englewood Cliffs, NJ) is similar to a triglyceride with polycarboxylic acids with two to four carboxylic acid groups such as tricarballic acid replacing glycerol and saturated or unsaturated alcohols replacing the fatty acids (Schlicker and Regan, 1990). TATCA is sometimes called “retrofat” (Dziezak, 1989) and its synthesis has been described by Hamm (1984). TATCA has been suggested as a substitute for vegetable oils in margarine and salad dressings (Anon., 1990; Hamm, 1984; LaBarge, 1988). Margarines prepared with TATCA melted more quickly and were softer than vegetable oil margarine (Hamm, 1985). TATCA is not digested by animals, but when fed at medium to high concentrations (9%) resulted in anal leakage, depression, weakness, and fatalities. The deaths were attributed to starvation or laxative effects as a result of interference with nutrient absorption rather than to toxicity (Hamm, 1984 and 1985; LaBarge, 1988).

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Trialkoxycitrate (TAC) and trialkoxyglyceryl ether (TGE) were also investigated by Hamm (1984). Because the ester bonds in TAC are reversed from corresponding esters in triglycerides, the esters in the polycarboxylic acid fat substitutes are not susceptible to lipase hydrolysis, and do not contribute calories to the diet. Polymorphic behavior is exhibited during melting and TAC viscosity and surface tension are similar to corn oil. Thermal decomposition problems may prevent TAC from being used in frying oils. Trialkoxyglyceryl ether (TGE) production on a large scale is difficult and time-consuming (Hamm, 1984; LaBarge, 1988). TGE exhibits viscosities and surface tensions similar to vegetable oils at room temperature. While functional properties may allow TGE use as a fat substitute, synthesis problems will make commercial production difficult (Artz and Hansen, 1994; Hamm, 1984; LaBarge, 1988). Dialkyl dihexadecylmalonate (DDM) (Frito-Lay, Inc., Dallas, TX) is a mixture of hexadecyl dioleylmalonate and dihexadecyl dioleylmalonate fatty acid esters of malonic and alkylmalonic acids which exhibit thermal stability (Dziezak, 1989; Fulcher, 1986; Gillis, 1988). Small molecular weight DDM are synthesized by reacting a malonyl dihalide with a fatty alcohol. Larger molecular weight DDM require the addition of an alkyl halide in a basic solvent (Artz and Hansen, 1994). DDM is noncaloric and absorption is negligible (Fulcher, 1986). Frying of potato and tortilla chips in DDM produces crisp chips with reduced oiliness (Anon., 1990). Esterified propoxylated glycerols (EPG) (Arco Chemical Company, Newtown Square, PA) are produced by reacting glycerine with propylene oxide to form a polyether polyol subsequently esterified with fatty acids (Anon., 1990; Gillis, 1988; Schlicker and Regan, 1990; Sowinski, 1991; White and Pollard, 1989). The structure of EPG is similar to triglycerides, except that an oxypropylene is incorporated between the glycerol and the fatty acids. Although many polyols are acceptable, the glycerol triol is preferred. Preferred fatty acids are in the C14 to C18 range, and preferred sources of fatty acids are soybean, olive, cottonseed, corn oil, tallow, and lard (Whilte and Pollard, 1989). EPG is low-to-noncaloric, heat stable (Anon., 1990; Arciszewski, 1991; Dziezak, 1989), and partially digestible (White and Pollard, 1989). EPG feeding studies with rats indicate no toxicity (White and Pollard, 1989). Polydextrose, derived from glucose, sorbitol, and citric acid, can also be esterified with C8-C22 fatty acids to produce polydextrose derivatives of potential value as fat substitutes (Vianen et al., 1991). Phenylmethylpolysiloxanes (Dow Corning 550 Gluid, Contour Chemical Co., North Reading, MA) are organic derivatives of silica (SiO2) with a linear polymeric structure consisting of the generic formula [–R2SiO], where the R is an organic radical such as a methyl, phenyl, or other aliphatic or aromatic hydrocarbon (Bracco et al., 1984). Polysiloxanes are chemically inert, nonabsorbable, and nontoxic, with viscosities ranging from 0.65 to 106 centistokes (cs) at ambient temperature depending on molecular weight. Phenylmethylpolysiloxane is an oil that is similar in functionality to soybean oil, is oilsoluble, and exhibits lipid-like character in organic solvents. Similarly, phenyldimethylpolysiloxane (PDMS) (Dow Corning Corp., Midland, MI) is another potential noncaloric heat stable fat substitute (LaBarge, 1988). PDMS exhibits thermal and oxidative stability, minimal change in viscosity over a broad temperature range, water repellant ability, and biological inertness. The polysiloxanes possess physical, functional, and organoleptic properties of fats and oils that are inherent to unique silicon chemistry and are totally unrelated to glyceride structure. Polysiloxane has been shown to be a safe and effective calorie diluent in foods fed to experimental rats (Bracco et al., 1987).

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13.5 CONCLUSIONS The sucrose fatty acid polyester olestra is currently the only synthetic fat substitute with a petition in review by the U.S. Food and Drug Administration. A November, 1995 hearing on the safety of olestra before the FDA Food Advisory Committee resulted in a recommendation for approval. Final FDA approval for olestra is expected early in 1996. Beck concluded in 1992 that “synthetic fat research is dynamic and exciting; synthetic fat commercialization mostly isn’t.” Synthetic fat substitutes share not only structural similarities and bulk which simulate the properties of fat, but also chemical, sensory, and functional similarities, as well as a resistance to digestion by pancreatic lipases and absorption in the gastrointestinal tract. Synthetic fat substitutes are not a panacea for poor dietary habits. The effect of synthetic fat substitutes on reducing fat consumption remains to be seen, but at the very least, synthetic fat substitutes will improve the palatability and acceptability of reduced-fat foods (Sowinski, 1991; Swanson, 1992).

REFERENCES Akoh, C.C. and Swanson, B.G. Base-catalyzed transesterification of vegetable oils. J. Food Proc. Pres. 12(2), 139, 1988. Akoh, C.C. and Swanson, B.G., Carbohydrate Polyesters as Fat Substitutes, Marcel Dekker, NY, 1994, 269. Akoh, C.C. and Swanson, B.G., One-stage syntheses of raffinose fatty acid polyesters, J. Food Sci. 52, 1570, 1987a. Akoh, C.C. and Swanson, B.G., Preliminary raffinose polyester and methyl glucose polyester feeding trials with mice. Nutr. Rep. Int. 39, 659, 1987b. Akoh, C.C. and Swanson, B.G. Syntheses and functional properties of alkyl glycoside and stachyose fatty acid polyesters. J. Am. Oil Chem. Soc. 66, 1295, 1989a. Akoh, C.C. and Swanson, B.G. Preparation of trehalose and sorbitol fatty acid esters by interesterification. J. Am. Oil Chem. Soc. 66, 1581, 1989b. Akoh, C.C. and Swanson, B.G. Optimized syntheses of sucrose polyesters: Comparison of physical properties of sucrose polyesters, raffinose polyesters and salad oils. J. Food Sci. 55, 236, 1990. Akoh, C.C. Syntheses of carbohydrate fatty acid polyesters, in Carbohydrate Polyesters as Fat Substitutes, Akoh, C.C. and Swanson, B.G., Eds., Marcel Dekker, NY, 1994, chap. 2. Anonymous. Fat substitute update. Food Technol. 44(3), 92, 1990. Albano-Garcia, E., Lorica, R.G., Pama, M., and de Leon, L. Solventless synthetic methods for methyl glycoside and sorbitol esters of coconut fatty acids. Phillipp. J. Coconut Stud. 5, 51, 1980. D’Amelia, R.P. and Jacklin, P.T. Polyvinyl oleate as a fat replacement. U.S. Patent 4,915,974, 1990. Arciszewski, H. Fat functionality, reduction in baked foods. Inform 2(4), 392, 1991. Artz, W.E. and Hansen, S.L. Other fat substitutes. In Carbohydrate Polyesters as Fat Substitutes, Akoh, C.C. and Swanson, B.G. Eds., Marcel Dekker, NY, 1994, chap. 11. Barth, R.W., Park, R., and Burrell, C. Polyhydric alcohol esters. U.S. Patent 2,356,745, 1944. Beck, C.I. What’s really happening with synthetic fats? Conference on Fat and Cholesterol Reduced Foods, International Business Communications, Stratecon, Winston-Salem, NC 1992. Bjorkling, F., Godtfredsen, S.E., and Kirk, O. A highly selective enzyme-catalyzed esterification of simple glycosides. J. Chem. Soc. Chem. Comm. 934, 1989. Boutte, T.T. Methyl glucose and sucrose polyesters: Feeding studies and interactions with supercritical carbon dioxide. Ph.D. Dissertation, Washington State University, Pullman, 1993, 125. Bracco, E.F., Baba, N., and Hashim, S.A. Polysiloxane: potential non-caloric fat substitute; effects on body composition of obese Zucker rats. Am. J. Clin. Nutr. 46, 784, 1987. Feuge, R.O., Zeringue, Jr., H.J., Weiss, T.J., and Brown, M. Preparation of sucrose esters by interesterification. J. Am. Oil Chem. Soc. 47, 56, 1970. Finley, J. W., Klemann, L. P., Leveille, G. A., Otterburn, M. S., and Walchak, C. G., Caloric availability of Salatrim in rats and humans, J. Agric. Food Chem., 42, 495, 1994.

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Decombaz, J., Ananthraman, K., and Hesie, C. Nutritional investigations on jojoba oil. J. Am. Oil Chem. Soc. 61(4), 702, 1984. Drake, M.A., Boutte, T.T., Younce, F.L., Cleary, D.A., and Swanson, B.G. Melting characteristics and hardness of milkfat blend sucrose polyesters. J. Food Sci. 59, 652, 1994a. Drake, M.A., Boutte, T.T., Luedecke, L.O., and Swanson, B.G. Milkfat sucrose polyesters as fat substitutes in Cheddar-type cheeses. J. Food Sci. 59, 326, 1994b. Drake, M.A., Ma, L., Swanson, B.G., and Barbosa-Cánovas, G.V. Rheological characteristics of milkfat and milkfat-blend sucrose polyesters. Food Res. Int. 27, 477, 1994c. Dziezak, J.D. Fats, oils and fat substitutes. Food Technol. 43(7), 66, 1989. Fulcher, J. Synthetic cooking oils containing dicarboxylic acid esters. U.S. Patent 4,582,927, 1986. Gibbons, J.P. and Swanson, C.J. Methyl glucoside fatty acid diesters. J. Am. Oil Chem. Soc. 36, 553, 1959. Gillis, A. Fat substitutes create new ideas. J. Am. Oil Chem. Soc. 65(11), 1708, 1988. Hamm, D.J. Low calorie edible oil substitutes. U.S. Patent 4,508,746, 1985. Hamm, D. J., Preparation and evaluation of trialkoxytricarballate, trialkoxycitrate, trialkoxyglceryl-ether, jojoba oil and sucrose polyester as low calorie replacements of edible fats and oils, J. Food Sci., 49, 419, 1984. Hass, H.B. Early history of sucrose esters, in Sugar Esters, Noyes Development Corporation, Park Ridge, NJ, 1968, 1. Hayes, J. R., Pence, D. H., Sheinbach, S., D’Amelia, R. P., Klemann, L. P., Wilson, N. H., and Finley, J. W., Review of triacyglycerol digestion, absorption, and metabolism with respect to Salatrim triacylglycerols, J. Agric. Food Chem., 42, 474, 1994. Hayes, J. R. and Riccio, E. S., Genetic toxicology studies of Salatrim structured triacylglycerols. 1. Lack of mutagenicity in the Salmonella/microsome reverse mutation assay, J. Agric. Food Chem., 41, 515, 1994. Hayes, J. R., Wilson, N. H., Pence, D. H., and Williams, K. D., Subchromic toxicity studies of Salatrim structured triacyglycerols in rats. 1. Triacylglycerols composed of stearate and butyrate, J. Agric. Food Chem., 42, 528, 1994a. Hayes, J. R., Wilson, N. H., Pence, D. H., and Williams, K. D., Subchromic toxicity studies of Salatrim structured triacylglycerols in rats. 3. Triacylglycerols composed of stearate, acetate, propionate and butyrate, J. Agric. Food Chem., 42, 552, 1994b. Hayes, J. R., Wilson, N. H., Roblin, M. C., Mann, P. C., and Kiorpes, A. L., 28-day continuous dosing study in minipigs with a Salatrim structured triacylglycerol composed of stearate, acetate and propionate, J. Agric. Food Chem., 42, 563, 1994c. Hendrick, A.E. and Reimer, R.A. Fat-coated microparticulate low calorie fat substitutes. European Patent 380, 225, 1990. Jandacek, R.J. The development of Olestra, a non-caloric substitute for dietary fat. J. Chem. Edu. 68(6), 476, 1991. Jandacek, R.J. and Webb, M.R. Physical properties of pure sucrose octaesters. Chem. Phys. Lipids 22, 163, 1978. Klemann, L. P., Aji, K., Chrysam, M. M., D’Amelia, M.D., Henderson, J. M., Huang, A. S., Otterburn, M. S., and Yarger, R. G., Random nature of triacylglycerols produced by the catalyzed interesterification of short- and long-chain fatty acid triglycerides, J. Agric. Food. Chem. 42, 442, 1994. LaBarge, R.G. The search for a low calorie oil. Food Technol. 42(1), 84, 1988. Linares, M. Methyl glucoside polyesters of lard fatty acids application in pork sausage. M.S. Thesis, Washington State University, Pullman, 1995, in review. McCoy, S.A., Madison, B.L., Self, P.M., and Weisgerber, D.J. Sucrose polyesters which behave like cocoa butters. U.S. Patent 4,822,875, 1989. Mascioli, E. A., Babayan, B. K., Bistrian, B. R., and Blackburn, G. L., Novel triglycerides for special medical purposes, J. Parenteral. Enteral. Nutr., 12(6), 1285, 1988. Matthews, D. M., and Kennedy, J. P., Structured lipids, Food Technol., 44(6), 127, 1990. Mieth, G., Eisner, A. and Weiss, A. Zur synthese und characktersierung von saccharose-fettsaure polyestern, 1. Mitt. uber ein neues synthese ver fahren. Die Nahrung 27, 747, 1983. Minich, A. Dietetic compositions. U.S. Patent 2,962,419, 1950. Myhre, D.V. Process for the preparation of fatty acids of sugar glycosides. U.S. Patent 3,597,417, 1971. Ranhotra, G.S. and Gelroth, J.A. Nutritional considerations of jojoba oil. Cereal Foods World 34(10), 876, 1989.

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Riva, S. Enzymatic synthesis of carbohydrate esters. In Carbohydrate Polyesters as Fat Substitutes, Akoh, C.C. and Swanson, B.G., Eds., Marcel Dekker, NY, 1994, chap. 3. Rizzi, G.P. and Taylor, H.M. A solvent free synthesis of sucrose polyesters. J. Am. Oil Chem. Soc. 55, 398, 1978. Rizzi, G.P. and Taylor, H.M. Syntheses of higher polyol fatty acid polyesters. U.S. Patent 3,963,699, 1976. Rudolph, M. J., Greenwald, C. J., and Flesch, R. P., Fat replacers: U.S. markets and technologies, Spectrum Food Industry, Decision Resources, 1991, 14.1. Schlicker, S.A. and Regan, C. Innovations in reduced-calorie foods: A review of fat and sugar replacement technologies. Topics Clin. Nutr. 6(1), 50, 1990. Seino, H., Uchibori, T., Nishitani, T., and Inamasu, S. Enzymatic syntheses of carbohydrate esters of fatty acid. Esterification of sucrose, glucose, fructose and sorbitol. J. Am. Oil Chem. Soc. 61, 1761, 1984. Singhal, R. S., Gupta, A. K., and Kulkarni, P. R., Low-calorie fat substitutes. Trends Food Sci. Technol., October, 241, 1991. Smith, R. E., Finley, J. W., and Leveille, G. A., Overview of Salatrim, a family of low calorie fats, J. Agric. Food Chem., 42, 432, 1994. Softly, B. J., Huang, A. S., Finley, J. W., Petersheim, M., Yarger, R. G., Chrysam, M. M., Wieczorek, R. L., Otterburn, M. S., Manz, A., and Templeman, G. J., Composition of representative Salatrim fat preparations, J. Agric. Food Chem., 42, 461, 1994. Sowinski, S.A. Update on fat-free substitutes. SCAN’s Pulse, 3, Fall, 1991. Swanson, B.G. Synthetic fat substitutes. Abstract No. 234, International Food Technology Exposition and Conference (IFTEC), the Hague, Netherlands, 1992. Swanson, B. G., and Akoh, C. C., A background and history of carbohydrate polyesters, in Carbohydrate Polyesters as Fat Substitutes, Akoh, C. C. and Swanson B. G., Eds., Marcel Dekker, NY, 1994, chap. 1. Toma, R.B., Curtis, D.J., and Sobotor, C. Sucrose polyester: Its metabolic role and possible future applications. Food Technol. 42(1), 93, 1988. Venardos, J.P. Mailbox. Genetic Engineering News, April 15, 1995, 4. Vianen, G.M., Koerts, K., and Kuzee, H.C. Low-calorie polydextrose derivatives. Eur. Patent 416, 670, 1991. Wei, J-J. Synthesis and feeding studies of sucrose fatty acid polyesters — Utilized as simulated milkfat. Ph.D. Dissertation, Washington State University, Pullman, 135, 1984. White, J.F. and Pollard, M.R. Non-digestible fat substitutes of low caloric value. U.S. Patent 4,861,613, 1989. White, J.F. and Pollard, M.R. Non-digestible fat substitutes of low caloric value. Eur. Patent 325,010, 1989. Winsniak, J., Jojoba Oil and Derivatives, Progress in the Chemistry of Fats and Other Lipids, Vol. 15, Pergamon Press, NY, 1994, 167. Yamamoto, T. and Kinami, K. Production of sucrose fatty acid polyester. U.S. Patent 4,611,055, 1986. Yang, C-M. Inhibition of salad dressing spoilage organisms by sucrose and methylglucose fatty acid monoesters. M.S. Thesis, Washington State University, Pullman, 63, 1993.

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Appendix

Classified List of Fat Replacers and Their Applications* Sylvia A. Jones

The following table groups fat replacers according to the classification presented in Chapter 1 (Section 1.4.2). In each group, the fat replacers are listed in alphabetical order of their trade names (or common names). This should enable the reader to easily locate a particular fat replacer in the table. It should be noted that, while registered trademarks are not included in the table, the majority of the trade names do in fact carry registered trademarks and the ownership of these belong to the developers or manufacturers which are given in the fourth column of the table. Other information given in the table includes chemical name/composition (with origin of the base material and processes used, where appropriate and when available), the concentration at which the fat replacer is normally used, special features, and applications in foods. All the information given in the table has been compiled over the years at the Leatherhead Food Research Association from published data, ingredient launches, and company brochures, and is exclusively concerned with those ingredients that have been purposely developed, or, in the case of established ingredients, have been claimed and used to replace some of the functional properties of fats in terms of mouthfeel, structural, or textural characteristics. Hence, the list deliberately does not include those ingredients which have been developed to provide only the flavors associated with particular fats or oils. Furthermore, standard basic ingredients (e.g., gelatin, caseinate, other proteins, and starches) are omitted in order to simplify the table, although, as discussed in Chapters 1 and 4, it is well recognized that some play useful supporting roles in replacing fat in * Reproduced from Jones, S. A., Fat replacers database, Leatherhead Food Research Association. With permission.

©1996 CRC Press LLC

certain products. On the other hand, some fat replacers that made an impact at one time but were either not commercialized or their production has subsequently been discontinued, are included in the list, and the significance of these is made apparent in Chapter 1 and Chapter 4. Finally, synthetic fat substitutes are included in the table. At the time of writing, they remained only as possible concepts for fat replacement in the future, since, so far, none have been approved for use in foods. As mentioned in Chapters 1 and 13, petitions for the use of olestra in foods have been with the FDA since 1987, and a final decision was expected before the end of 1995. It should be noted that, although the table includes nearly 300 individual ingredients or systems introduced by different companies, absence from the list does not have any negative implications. Furthermore, the inclusion in this list of a fat replacer from a particular manufacturer does not indicate preferential endorsement of a product.

©1996 CRC Press LLC

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Starch-derived

Amalean I

Modified high amylose corn starch

American Maize Products Company, IN, USA

1–8%

Starch-derived

Amalean Instant II

Modified high amylose starch

American Maize Products Company, IN, USA

Gel forms at 25% solids

Starch-derived

C*Pur 01906 C*Pur 019R7

Cerestar SA/NV, Brussels, Belgium

1–2% in salad dressings, 3–10% in margarine spread

Starch-derived

CrystaLean

Dairytrim

Starch-derived

Debranched Araban

Starch-derived

Enzymically debranched starch

Starch-derived

Instant Pure-Flo

Opta Food Ingredients Inc., MA, USA; (to be manufactured by -) National Starch & Chemical Co., NJ, USA Partnership — Quaker Oats Company, IL, USA and Rhone-Poulenc Food Ingredients, NJ, USA British Sugar plc., Peterborough, UK National Starch & Chemical Company, Food Product Division, NJ, USA National Starch & Chemical Company, Food Product Division, NJ, USA

Highly crystalline maltodextrin with high fiber content

Starch-derived

Potato maltodextrin (enzymic process) 01906-DE 2–5 019R7-DE 3–7 Maltodextrin (physical and biochemical process) from a hybrid variety of high amylose corn; 30% dietary fiber Hydrolyzed rice and oat flour

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Enzymically debranched sugar beet araban Partially enzymically debranched waxy maize starch HP waxy corn starch

Applications Cheesecake, pour/spoonable salad dressings, sauces, cream fillings, dips, spreads, bakery, dairy products Bakery, sauces, gravies, soups, salad dressings, dairy products, dips, icings, cheese spreads, desserts Salad dressings, sauces, ice cream, butter cream, margarine, processed meats Extruded and baked foods, biscuits, crackers, cookies

Spreads, dips, cookies, processed cheese, frozen desserts So far not commercialized So far not commercialized

Low-fat spreads, ice cream, chilled or frozen desserts Dressings, ice cream, pork pie fillings and pastry Bakery products, instant desserts

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Starch-derived

Leanbind

Modified starch

Starch-derived

LoDex 5 LoDex 10

Maltodextrin from waxy maize starch

Starch-derived

Lycadex 100

100 = Potato maltodextrin DE < 5 (enzymic process) 200 = Corn maltodextrin DE <5 Corn starch maltodextrin DE 4 Corn starch maltodextrin DE 9–13 Corn starch maltodextrin DE 14–18

Roquette, Lille Cedex, France

National Starch & Chemical Company, Food Product Division, NJ, USA National Starch & Chemical Company, Food Product Division, NJ, USA

Lycadex 200 Starch-derived

Maltrin M040 Maltrin M100 Maltrin M150

Starch-derived

N-Lite B

Waxy maize maltodextrrin

Starch-derived

N-Lite CL

Modified food starch

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Concentration Used/ Special Features

National Starch & Chemical Company, Food Product Division, NJ, USA American Maize Products Company, IN, USA

Grain Processing Corporation, IA, USA

Applications Meat, fish and poultry products

100 — Gel forms at 25% solids 200 — Gel forms at 10–20% solids (M040 — soluble in hot water, M100 — readily soluble in water)

Baby foods, bakery products and ingredients, beverages, breakfast cereals, sauces, confectionery, dairy products, desserts, salad dressings, spreads, icings, frozen novelties, soups, gravies, snack foods, puddings Salad dressings, spreads, bakery products, ice cream

Gel forms at 25–30% solids

Bakery and snack foods, beverages, confectionery, dairy products, salad dressings, dips, margarine, spreads, frozen desserts, meat, fish and poultry products Bakery products

For use in flavor sensitive systems

Milk drinks, ice cream, yogurt

Starch-derived

N-Lite D

Modified starch

National Starch & Chemical Company, Food Product Division, NJ, USA National Starch & Chemical Company, Food Product Division, NJ, USA

2–4%

Dairy products

Starch-derived

N-Lite L

Modified waxy maize starch

2–10%

Modified waxy maize starch (liquid/pregel)

National Starch & Chemical Company, Food Product Division, NJ, USA

2–10%

N-Lite S

Modified waxy maize starch

National Starch & Chemical Company, Food Product Division, NJ, USA

2%

Starch-derived

N-Lite SP

Modified waxy maize starch (liquid/pregel)

National Starch & Chemical Company, Food Product Division, NJ, USA

2–3%

Starch-derived

N-Oil Instant N-Oil Instant N-Oil II

N-Oil and Instant N-Oil = Tapioca dextrins, Instant N-Oil II = instant tapioca maltodextrin

National Starch & Chemical Company, Food Product Division, NJ, USA

Usually incorporated as 25% solids dispersion which forms a gel system

Starch-derived

Navadex 120-01 Navadex 120-10

Hydrolyzed oat flour 120-01-DE 1 120-10-DE 10

National Oats Co., IA, USA (division of Curtice Burns Foods Inc., NY, USA)

Starch-derived

Novelose

Maltodextrin (physical and biochemical process) from a hybrid variety of high amylose corn; minimum 15% resitant starch

National Starch & Chemical Company, Food Product Division, NJ, USA

Liquid systems (process temp. > 65∞C for > 5 min) e.g., salad dressings, soups, sauces Cold process — liquid systems, e.g., pourable salad dressings, dry mix soups, sauces Liquid systems (process temp. > 70∞C for > 5 min), e.g., spoonable salad dressings, soups, dips, sauces, vinaigrette Liquid pregel systems, e.g., salad dressings, microwave soup and sauce mixes, instant dessert mixes Confectionery, soup, frozen desserts, spoon/pourable salad dressings, sour cream type products, yogurt, sauces, gravies, puddings Cookies, baked goods, salad dressings, soups, sauces, puddings, ice creams and dairy products Extruded products, bakery products, fiber fortified RTE cereals, pasta, snacks

Starch-derived

N-Lite LP

Starch-derived

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Maltodextrin with high fiber content

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Starch-derived

OptaGrade

High-amylose corn starch (physically modified)

Opta Food Ingredients Inc., MA, USA

Suitable for no-fat applications, provides opacity

Starch-derived

Paselli SA2 Paselli Excel

Potato maltodextrin (enzymic process; DE 2)

Avebe America Inc., NJ, USA

Minimum concentration — 20% solids to form a gel system Paselli Excel — cold water soluble, flavor free

Starch-derived

Pure-Gel B-990

Modified corn starch

Grain Processing Corporation, IA, USA

Starch-derived

Quaker Oatrim Quaker Oatrim Quaker Oatrim Quaker Oatrim Pro-Oatrim

Enzymically hydrolyzed oat flour; typically 5% β -glucan, DE 5; Pro-Oatrim — watersoluble

Based on USDA patented process for Oatrim; Licensed to partnership — Quaker Oats Company, IL, USA & Rhone-Poulenc Food Ingredients, NJ, USA

1–10% Typically gel formed at 25% solids and used after 24h refrigeration period

Starch-derived

Remyline range Remygel range

Remyline — Starch from waxy rice hybrids (amylopectin/amylose ratio = 98: 2) Remygel — Modified starch from waxy rice hybrids

REMY Industries S.A., Leuven, Belgium/A&B Ingredients Inc., NJ, USA

1–5% (Stable to freeze-thaw cycles, sterilisation, and acid conditions)

©1996 CRC Press LLC

1 5 10 5Q

Applications Fermented dairy products, processed cheese, frozen desserts, salad cream, watercontinuous-margarine-type spreads Dressings, sauces, spreads, frozen desserts, toppings, cakes, butter creams and fillings Dips, spreads, sauces, gravies, sausages, ham and other meat products QO 5 — processed meat, bakery, prepared foods QO 5Q — delicately flavored applications. Generally — bakery products and ingredients, beverages, sauces, dairy products, meat, fish and poultry, salad dressings, soups, spreads Dairy products, baby foods, sauces, soups, salad dressings, mayonnaise, baked goods, margarine, frozen foods, ice cream, processed meats

Starch-derived

Rice*Trin Rice*Trin Rice*Trin Rice*Trin Rice*Trin

Starch-derived

3 Complete 10 Complete 18 Complete 10 18

Zumbro Inc., MN, USA

Rice-gel L-100

R*Trin 3, 10, 18 Complete — Enzymically hydrolyzed complete rice solids (10% protein, 90% maltodextrin at 3, 10 and 18 DE, repectively) R*Trin 10, 18 — Rice maltodextrin (10 and 18 DE, respectively) Rice Flour

Starch-derived

Slenderlean

Modified tapioca starch

1%

Starch-derived

Sta-Slim 142

Modified potato starch (instant) Modified potato starch (cookup) Modified tapioca starch (instant) Modified tapioca starch (cook-up) Modified starch Agglomerated waxy corn maltodextrins

National Starch & Chemical Company, Food Product Division, NJ, USA A. E. Staley Manufacturing Company, IL, USA

2–4%

142, 143, 151, 150 — Bakery, sauces, dairy, desserts, salad dressings, soups 171 — Meat, fish, poultry products

A.E. Staley Maufacturing Company, IL, USA

Available as DE 1, 5, 10, or 15. High bulking ability

California Natural Products, CA, USA

1–3%

Bakery, beverages, sauces, dairy, desserts, salad dressings, soups SPR — Puddings, baked goods SPW-LP — Frozen products

Sta-Slim 143 Sta-Slim 150 Sta-Slim 151

Starch-derived

Sta-Slim 171 Star-Dri range

Starch-derived

StarchPlus SPR StarchPlus SPW-LP

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SPR — Natural rice starch from medium-grained rice SPW-LP — native starch from high-amylopectin short-grain rice

3–6% Gels at > 15% conc. in water. Also available in agglomerated form — Insta*Rice*Trin Complete

Rivland Partenership, USA

Bakery products, bakery ingredients, breakfast cereal, baby foods, sauces, dairy products, meat, fish and poultry products, salad dressing, cheese spread, cream cheese, desserts

Meat, fish and poultry products Sausage and ground beef products

Group Starch-derived

Trade Name/ Common Name Stellar

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Acid hydrolyzed corn starch crystallites

A. E. Staley Manufacturing Company, IL, USA

High shear (> 8,000 psi) required at 20–25% solids Low temperature stability (up to 70∞C)

Crystalline particles of modified golden pea carbohydrate, (90% carbohydrate — in that 10% dietary fiber) Partially pre-gelatinized starch derived from cassava flour Enzymically hydrolyzed oat flour; typically 5% β -glucan, DE 5; OC — 2–3% β -glucan B-Trim = Reduced viscosity form

Woodstone Foods Corporation, Manitoba, Canada

Absorbs 10 times their weight of cold water and 12 times their weight of hot water

Tipiak Inc., Pont-St-Martin, France/Fibrisol Service Ltd., London, UK (agent) Based on USDA patented process for Oatrim; licensed to partnership — ConAgra, NE, USA and A. E. Staley Manufacturing Company, IL, USA = Mountain Lake Manufacturing

2–3% in sausages Available in granulated, powder and flake forms 1–10% Typically gel formed at 25% solids and used after 24h refrigeration period

Concentrated from the cell walls of oat groats, rich in soluble and insoluble dietary fiber Microcrystalline cellulose (MCC), alginate salts

Alko Ltd., Rajamaki, Finland/ A&B Ingredients Inc., NJ, USA FMC Corporation, PA, USA

Instant Stellar

Starch-derived

Still-Water Crystals

Starch-derived

Tapiocaline range

Starch-derived

TrimChoice (Oatrim) = TrimChoice 5 TrimChoice OC B-Trim

Fiber-based

Alko oat bran concentrate (OBC)

Fiber-based

Avicel AC-815

©1996 CRC Press LLC

Concentration Used/ Special Features

Applications Baked goods, frostings, fillings, gravies, sauces, dairy products, salad dressings, cheese products, soups, spreads, meat products, confectionery, frozen dairy desserts Baked goods, dairy products, and processed meats

Meat products, ready meals, sauces, dairy products Salad dressing, mayonnaise, meat products, baked goods, confectionery, ice cream, beverages, sauces, gravies, soups, cheese, margarine, dietetic foods, spreads, pet foods Bakery products, breakfast cereals, etc.

1% Enhanced flavor release; opacity

Bakery products, sauces

Fiber-based

Fiber-based

Avicel FD-006 Avicel FD-100 Avicel PH-105 Avicel LM Avicel RC-501 Avicel RC-581 Avicel RC-591F Avicel CL-611 Better Basics Advanced Oat Fibre White (780) Tan (770) Extra-fine (782) Cellulon

Fiber-based

Cellulose Powder

Fiber-based

Centu Tex Centara II

Golden Pea Fiber

Fiber-based

Enzymically hydrolyzed cellulose

Mixture of oligomers derived by the degradation (enzymic, chemical or physical) of a cellulose derivative — CMC, Methyl Cellulose, Methyl Ethyl Cellulose

Fiber-based

©1996 CRC Press LLC

FD and PH — Powdered grades of micro crystalline cellulose (MCC) LM — Reduced porosity MCC RC and CL — Colloidal grades. i.e., co-processed MCC and CMC Oat fiber

FMC Corporation, PA, USA

0.2–5.0% High shear required for all grades FD — Liquid foods, LM — Low moisture foods, RC/CL — Improved dispersability

Salad dressings, dips, spreads, bakery products, dairy products, ice cream, and frozen desserts, meat products

Williamson Fibre Products, County Cork, Ireland

3–6%

Bacterial cellulose obtained through aerobic fermentation using Acetobacter strain (93–95% cellulose) Alpha-cellulose

The Weyerhaeuser Company, Washington, D.C./MD, USA

Available as wet product (approx. 20% solids) and in a dry form. Fine fiber structure; high surface area

Processed meats, ice cream, batter coated products and deep fried food, chocolate, mayonnaise, spreads, frozen yogurt, danish pastry Pourable/spoonable dressings, frozen desserts, sauces

J. Rettenmaier and Sohne GmbH and Co., Rosenberg/Holzm, Germany Woodstone Foods Corporation, Manitoba, Canada Alko Ltd., Rajamaki, Finland

High in pectin and hemicellulose. High water absorption capacity

Baked goods, pasta, cheese, soups, sauces, fat spreads, comminuted meats, meat/fish spreads Low calorie icings

Cakes, icing, mayonnaise, spreads, margarine, pate (other meat emulsions), cookies, snack fillings, creams, confectionery, extruded snacks, cereals, batters for frying

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Fiber-based

Ex-Cel

Processed cellulose gum with sodium CMC

Functional Foods Corp., USA

Fiber-based

Fibercel

Beta-Glucan fiber derived from yeast

Alpha-Beta Technology, Inc. MA, USA

Fiber-based

Fibrex

Hemicelluloses from sugar beet pulp

Delta Fibre Foods Inc., MN, USA

Fiber-based

Fibrim Fibrim Fibrim Fibrim

Fiber derived from cell wall material of soybean cotyledon

Protein Technologies International, NJ, USA

©1996 CRC Press LLC

1020 1250 1255 1450

Concentration Used/ Special Features

(Only permitted under current FDA legislation to be used in some cold processed products e.g., dressings)

Applications Bakery products, beverages, sauces, confectionery, dairy products, desserts, fruits and vegetables, meat, fish and poultry products, salad dressings, mayonnaise, snack foods Ice cream, frozen yogurt, cheese products, processed meats, puddings, mayonnaise, salad dressings, frostings and icings, fillings, beverages, soups, canned foods, breads Baby foods, bakery products and ingredients, beverages, breakfast cereals, sauces, confectionery, dairy products, desserts, fruit and vegetables, meat, fish and poultry products, pet foods, salad dressings, soups, snack foods 1020 — Liquid beverages 1250 — RTE cereals 1255 — Extruded snacks and low calorie baked goods 1450 — High fiber and reduced calorie baked goods

Fiber-based

Fibruline

Inulin (fructose polymers, DP 2–60, with one glucose unit); obtained from chicory root Hemicellulose

Cosucra SA, Momalle, Belgium

Fiber-based

Hemicellulose

Fiber-based

Just Fibre

99% Dietary fiber Two varieties available — Powdered Alpha Cellulose, and Bleached Vegetable Fibre CL-35H — Cellulose CS-35H — Cottonseed fiber

Filler Corporation, New York State, NY, USA and Lawrence Industries, Staffordshire, UK

Fiber-based

JustFiber CL-35H JustFiber CS-35H

Fiber-based

Lean Maker

Oat bran and oat fiber based product

Fiber-based

Methocel Hydroxypropylmethylcellulose

Methylcellulose (MC) Hydroxypropylmethylcellulose (HPMC)

Heller Seasonings and Ingredients, IL, USA (Main Ingredient Supplied by Quaker Oats Company, IL, USA) The Dow Chemical Co. MI, USA

Fiber-based

Opta Oat Fibers

Fiber derived from oat hulls

©1996 CRC Press LLC

5–40% Stable at temp < 85∞C and down to pH 2. Bifidus stimulating properties

The NutraSweet Company, IL, USA

Mayonnaise, salad dressing, butter substitutes, cheeses, dips, sour cream substitutes, whipped topping, spreads, sauces Bakery products, meat products, spreads, salad dressings, sauces

Van den Bergh, Food Ingredients Group, IL, USA

Opta Food Ingredients Inc., MA, USA/Pfizer Inc., Food Science Group, New York, USA

Ice cream, cheese spreads, chocolate, dressings, meat products

3% in low-fat meat 5% in pork sausages

Form gels on heating; on cooling reverse to pseudoplastic flow

Dairy products, salad dressings, bakery products, beverages Meat, fish and poultry products, e.g., ground beef products, pork sausages (Potentially — bologna, hot dogs, pizza toppings) Fried foods, salad dressings, sauces, bakery products, frozen cheesecake, whipped toppings Bakery products, fried foods, extruded products, frozen desserts, pasta

Group

Trade Name/ Common Name

Fiber-based

P-Fiber 150

Fiber-based

Potex Potex PPC

Fiber-based

Raftiline Raftiline Raftiline Raftiline Raftiline

Fiber-based

Snowite

Fiber-based

Sofalite F179 Sofalite M176

©1996 CRC Press LLC

GR HP LS ST ST-Gel

Chemical Name/ Composition Pea fiber 150C — Coarse, particles 1-2 mm 150M — Medium ground, particles 200 mm 150F — Fine ground, particles 30 mm Potato fiber (75% dietary fibers (-cellulose, pectin, hemi-cellulose, lignin), 10% starch and other carbohydrates, 0.3% fat) Inulin (fructose polymers, DP 2 - 60, with one glucose unit) obtained from chicory root GR — Granulated HP — High Performance LS — Low Sugar (2%) ST — Standard (8% sucrose) ST-Gel — Instant Alkaline peroxide treated oat fibers

Prepared by separation, purification, drying and grinding of specific pea species

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Applications

Grindsted (now Danisco Ingredients), Brabrand, Denmark

150M/F — 3% in liver paste or luncheon meat; 150C — 17% in marzipan

Meat products — (sausages, pate, liver paste, luncheon meat), also mayonnaise, dressings, marzipan

Agri Plot (part of Swedish Potato Co.)/Avebe America Inc., NJ, USA

Able to withstand conditions of low pH, high temp., freeze-thawing

Meat products, bakery products, ketchup

Orafti (previously Raffinerie Tirlemontoise) Belgium and Rhone-Poulenc Food Ingredients, NJ, USA

Bifidus stimulating

Bakery products and ingredients, beverages, confectionery, dairy products, desserts, meat, fish and poultry products, spreads, ice cream, yogurt, soft cheese

2–10%

F179 — dairy products, desserts, meat products, M176 — cooked sausages, pate, veg/meat/fish terrines

Canadian Harvest USA, MN, USA (Company formed jointly by DuPont and ConAgra, NE, USA) Sofalia, Paris, France

Fiber-based

Solka-Floc 900 FCC

100% Cellulose (Beta 1 - > 4 glucan polymer)

Fibre Sales and Development Corp. (subsidiary of Protein Technologies International, NJ, USA)/James River Corp.

Various fiber lengths and bulk volumes available

Fiber-based

Swelite

Pea fibers from the inner fibers of the pea kernel, (2/3 insoluble cellulose and 1/3 soluble pectic substances)

Cosucra SA, Momalle, Belgium

1–50% High-shear processing aids its water retention properties

Fiber-based

Tabulose Tabulose Tabulose Tabulose

BLANVER FARMOQUIMICA LTDA (Brazil)/BLANVER USA (New Jersey)/ZetaPharm, Inc.

0.5–20%

Fiber-based

UltraCel range

101 and 102 — Powdered microcrystalline cellulose SC-601 and SC-681 — Colloidal microcrystalline cellulose and sodium carboxymethylcellulose Microdisassembled fiber product derived from refined cellulose matrices

Watson Foods Co. Inc., CT, USA

0.35–2.50% Synergistic with xanthan gum, CMC, and galactomannans; unaffected by high temp., high salt, extreme pH, and freezethaw cycling

©1996 CRC Press LLC

101 102 SC-601 SC-681

Bakery products and ingredients, beverages, pasta, cakes, sauces, confectionery, dairy products, fruits and vegetables, salad dressings, meat, fish and poultry products, pet foods, soups, snack foods, cheese, frozen novelties Hamburgers, poultry products, sausages, vegetable products, soft cheese, ketchup, dressings, biscuits, extruded products Mayonnaise, salad dressings, sauces, dietary products, bakery products, imitation cheese products, canned meat products Bakery products, spreads, meat products, icing, coatings, soups

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Applications

Fiber-based

Vitacel range

Alpha-cellulose powder produced in several variants with varying fiber lengths

J. Rettenmaier and Sohne GmbH and Co., Rosenberg/Holzm, Germany

Bakery products and ingredients, beverages, sauces, dairy products, desserts, fruits and vegetables, pet foods, pasta, spreads, snack foods, cheese, soups, slimming foods and dietetic products, comminuted meats, meat/fish spreads, fat spreads

Protein-based

Complete Milk Protein (CMP-I)

Complete milk protein

American Dairy Specialties, USA

Protein-based

Dairy-Lo

Whey protein concentrate — partially denatured (60–80%)

Protein-based

Dairylight

Whey protein concentrate — partially denatured (60–80%)

Ault Foods Ltd., Canada. (Marketed and sold outside Canada by -) Pfizer Food Science Group, New York, NY, USA Ault Foods Ltd., Canada

Bakery products, beverages, sauces, confectionery, dairy products, desserts, meat, fish and poultry products, salad dressings, soups, snack foods, spreads As for Dairylight

Protein-based

Finesse

Containing piezo proteins — similar to Simplesse

©1996 CRC Press LLC

Reach Associates, Inc. NJ, USA

As for Dairylight (Dairylight was re-launched as DairyLo by Pfizer)

2–5% (Water binder and emulsifier)

Frozen desserts, ice cream, yogurt, cheese, spreads, sour cream, possibly nondairy products

Protein-based

Lactalbumin 75 Lactalbumin 70 SGH

Protein-based

Lactomil 9000 Lactomil HF

Protein-based

Lita A Lita C Lita D Lita KC

Protein-based

Miprodan

Protein-based

Nutrilac DR-6010 Nutrilac DR-7015 Nutrilac DR-8080 Nutrilac HA-7570 Nutrilac IC-7702 Nutrilac PSE-7 Nutrilac PSE-10 Nutrilac PSE-54 Nutrilac YO-5010 Nutrilac YO-5011 Nutrilac YO-7703

©1996 CRC Press LLC

Partially denatured milk protein % Protein/% Lactose/% Fat 75–75%/9.5%/6.0% 70 SGH — 72%/9.0%/6.0% Partially denatured milk protein % Protein/% Lactose/% Fat 9000 — 87%/0.5%/1.0% HF — 72%/10.5%/2.8% Microparticulated zein protein from corn gluten, coated with a polysaccharide A = 90% zein, 5% CMC, 5% gum arabic C = 95% zein, 5% CMC D = 100% zein KC = 95% zein 5% Kappa carrageenan Milk protein All derived from 100% milk ingredients. Whey protein concentrates obtained through extrusion to produce a semi-solid fat-like product with good spreadability and smooth consistency

MILEI, Germany

6–10%

Dairy based products: butter, frozen desserts, cream spreads, sour cream, ice cream

MILEI, Germany

6–10%

Dairy based products: butter, frozen desserts, cream spreads, sour cream, ice cream

Opta Food Ingredients Inc., MA, USA

Hydrophobic microparticulated protein

Frozen desserts, mayonnaise, sour cream, salad dressing, whipped topping, milk yogurt, non-dairy creamer, frosting, cream soups and sauces, cream/cottage cheese, dips, processed meats, chocolate and confectionery

MD Food Ingredients, Viby J, Denmark Danmark Protein A/S, Denmark Royal Proteins Inc., IL, USA

Ice cream YO-5010 and YO-5011 — 1.0–2.0%, YO-7703 — 0.6–2.5%, DR-6010 — 1.0–5.0%, DR-8080 — 0.5–4.0% (DR 6010 — needs heat treatment for best results)

YO — Yogurt and cultured products. DR-6010 — dressings, mayonnaise, sauces, dips. DR-8080 — Salad dressings, cold processed mayonnaise. IC7702 — dairy products. DR7015 — Salad dressings. HA-7570 — Meat, fish and poultry products

Group

Trade Name/ Common Name

Protein-based

Pea Protein

Protein-based

Simplesse 100

Protein-based

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Pea protein, extracted using water and an ultrafiltration process Whey protein concentrate — microparticulated protein Liquid form (42.5% solids, 23% protein, < 2% fat)

Feinkost Fine Ingredients, Germany

Simplesse 300

Egg white, skim milk, sugar and pectin — microparticulated protein Liquid form (22.7% solids, 11.8% protein)

The NutraSweet Company, IL, USA

Protein-based

Simplesse D-100

The NutraSweet Company, IL, USA

Protein-based

Simplesse D-500

Protein-based

Soy Protein Concentrate

Whey protein concentrate — microparticulated protein Dry form (54% protein, 36% sugars, < 4.5% fat) Whey protein concentrate — microparticulated protein Dry form (36% protein, 51% sugars, < 4.5% fat) 70% Protein 22% Dietary Fiber

©1996 CRC Press LLC

The NutraSweet Company, IL, USA

The NutraSweet Company, IL, USA

The Central Soya Company of Rotterdam, The Netherlands

Concentration Used/ Special Features

1–30% (Initally heat sensitive, later developed to withstand UHT, pasteurization and retorting conditions. 35 days shelf-life under refrigerated conditions) Production discontinued 1–20% (Higher viscosity than Simplesse® 100 Short shelf-life under refrigerated conditions) Production discontinued 1–30% Powder form with performance equal to original liquid form (S100) 4–5%

3%

Applications Meat products, dressings, sauces, baked products, biscuits Frozen desserts, dairy products, baked goods, salad dressings, spreads, sauces, toppings, frostings

Used exclusively by one food producer

As for Simplesse 100

Ice cream, frozen desserts

Meat and dairy products, patties, hamburgers, frankfurters, cream cheese, sour cream, dips, fillings, toppings, soup bases

Protein-based

Supro range

Isolated soy proteins

Protein Technologies International, NJ, USA

Protein-based

Trailblazer range

Microfragmented protein formed through protein/polysaccharide interaction, e.g., whey protein concentrate/egg white and xanthan Trailblazer II — Whey protein based Trailblazer III — Skim milk based

Kraft General Foods, IL, USA

Gums/gels/ thickeners

Aquagel Aquavis Milkgel Milkvis BenGel Benvisco Benlacta

Carrageenan

Marcel Carrageenan Inc., USA

Carrageenan

Shemberg USA, ME, USA

Gums/gels/ thickeners Gums/gels/ thickeners

Genu carrageenan

Iota carrageenan

Kelcogel range

Gellan gum

Hercules Food Ingredients Group, DE, USA Kelco Unit of Monsanto Co., CA, USA

Gums/gels/ thickeners

Kelcoloid LVF

Propylene glycol alginates (PGA)

Gums/gels/ thickeners

©1996 CRC Press LLC

Kelco Unit of Monsanto Co., CA, USA

Up to 20% by wt.(s) of the dispersion. KGF decided not to commercialize the Trailblazer range

Water holding capacity/skin formation

Meat products, non-dairy products, coffee creamers, pasta, soups, powdered and liquid beverages, food bars, and nutritional supplements Frozen desserts, spreads, dressings, sauces, cheese products, cultured dairy products, processed meat products, baked goods

Bakery products, beverages, sauces, confectionery, dairy products, meat products, salad dressings Dairy products, desserts, beverages, meat, fish and poultry products, salad dressings Meat products Margarines, spreads, cakes, cookies, dips, frozen desserts, salad dressings, sauces, gravies Margarine, spreads, salad dressings, sauces, gravies

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Gums/gels/ thickeners

Keltrol range

Xanthan gum

Kelco Unit of Monsanto Co., CA, USA

0.1–0.5%

Gums/gels/ thickeners

Konjac-N

Konjac flour (glucomannan) made from Devil’s Tongue Potatoes (tubers of Amorphophallus Konjac)

Earth House Corporation, CA, USA

High water retention ability Weak gel/paste forming

Gums/gels/ thickeners

Liangels Spraygum Gelamix Emulgum Nutricol Konjac Flour

Carrageenan Acacia gum Xanthan gum

Colloides Naturels International, Neuilly sur Seine, France

Glucomannan gum obtained from tubers of Konjac plant (Amorphophallus Konjac)

FMC Corporation, Food Ingredients Division, PA, USA

Gums/gels/ thickeners

Procol range

Guar gum

Polypro International, USA

Gums/gels/ thickeners

Rhodigel

Xanthan gum

Rhone-Poulenc Food Ingredients, NJ, USA

Gums/gels/ thickeners

Slendid 100 Slendid 110 Slendid 200

100 and 110 — Lowmethoxyl pectin from citrus peel (sodium salt) 200 — High-methoxyl pectin from citrus peel (calcium salt)

Copenhagen Pectin A/S, Denmark (Division of — Hercules Food Ingredients Group, DE, USA)

Gums/gels/ thickeners

©1996 CRC Press LLC

High water retention ability Forms thermally stable gels Synergism with kappacarrageenan or xanthan gum

0.4–1.5% 100 and 110 — require calcium ions to form gels (30mg Ca++/1g) and high shearing of the gels formed 200 — Water binder

Applications Salad dressings, sauces, frozen desserts, bakery products, margarine, spreads Sponge cake, soft biscuits, bread, frozen foods, sausages, processed meat and fish products, soups, sauces, dressings, ice cream

Cream soups, sauces, ground meats, mayonnaise, spreads

Salad dressings, sauces, soups, condiments, bakery products, frozen desserts Margarine, spreads, cakes, brownies, confectioery products, cookies, crackers, dips, frozen desserts, sauces, gravies Spreads, mayonnaise, dressings, processed meats, ice cream, processed cheese, desserts, bakery products

Gums/gels/ thickeners Gums/gels/ thickeners

Supercol F

Guar gum

Henkel Corp. IL, USA

Xanthan gum

Xanthan gum

Jungbunzlauer Inc., Switzerland

Instant products, soups, desserts, toppings, canned foods, frozen foods

Emulsifiers

Atmos range

Mono and diglycerides

Witco Corporation, (Chem. division) New York, NY, USA

Emulsifiers

Atmul range

Mono and diglycerides

Emulsifiers

DATEM GMS SSL

Emulsifiers

Dimodan range

DATEM — Diacetyl Tartaric Acid Ester of Monoglycerides GMS — Glycerol MonoSterate SSL — Soduim Stearol2-Lactylate Distilled Monoglycerides

Witco Corporation, (Chem. division) New York, NY, USA Available from all major producers/suppliers of emulsifiers

Bakery products and bakery ingredients, sauces, confectionery, dairy products, desserts, salad dressings, spreads Margarines, spreads, bakery products

Emulsifiers

Mono and diglycerides

Emulsifiers

Dur-Em 114 Dur-Em 117 Dur-Em 204 Dur-Lo

Mono and diglycerides

Van den Bergh, Food Ingredients Group, IL, USA

Emulsifiers

Emulsilac SK

Sodium stearoyl lactylate

Witco Corporation, (Chem. division) New York, NY, USA

©1996 CRC Press LLC

Grindsted (now Danisco Ingredients), Brabrand, Denmark Van den Bergh, Food Ingredients Group, IL, USA

DATEM — Biscuits GMS — Cakes, spreads, nondairy whipping systems SSL — Bread and biscuits

0.1–1.0%

Shortening substitute, butter, spreads, dough products Margarine, spreads, bakery products Bakery products and ingredients, dairy products, desserts Condiments, sauces, dairy products, pasta products

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Emulsifiers

Myvacet 9-45

Distilled acetylated monoglycerides

Eastman Chemical Co., TN, USA

Emulsifiers

Polyaldo range

Polyglycerol esters of fatty acids

Lonza Inc., NJ, USA

Emulsifiers

Triodan R90

Polyglycerol ester of interesterified ricinoleic acid

Grindsted (now Danisco Ingredients), Brabrand, Denmark

Bulking agents

Maltitol

Towa Chemical Industry Company Ltd

Bulking agents

Polydextrose Litesse Litesse II

Bulking agents

Sta-Lite

Polyalchohol (D-glucosyl(1-4)-D-glucitol), produced by the hydrogenation of maltose Polydextrose — polymer of glucose with sorbitol and citric acid, (89: 10: 1) Litesse — Improved polydextrose Litesse II — Super-improved polydextrose Polydextrose

Low-calorie fats

Aldo MCT

Medium Chain Triglyceride

©1996 CRC Press LLC

Concentration Used/ Special Features

Applications Bakery products and ingredients, breakfast cereals, sauces, dairy products, spreads Frozen desserts, margarine, shortenings, peanut butter, whipped toppings, and bakery goods w/o spreads

Pfizer Inc., Food Science Group, New York, NY, USA

Litesse — Reduced acidity, improved flavor; granular form available Litesse II — For flavor seneitive applications and higher fat reductions

A. E. Staley Manufacturing Company, IL, USA

Fast dissolving

Lonza Inc., NJ, USA

8.3 kcal/g. Lower tendency to form depot fat

Brownies, pie fillings, spreads, cakes, cookies, dry mixes, frozen desserts, salad dressings Pastry, confectionery products, dressings, spreads, bakery fillings, toppings, chilled desserts

Confectionary and bakery products

Low-calorie fats

Caprenin

Triglyceride composed of caprylic (C8:0), capric (C10:0) and behenic (C22:0) fatty acids

The Procter & Gamble Company, OH, USA

30% in milk chocolate, 5 kcal/g. Designed to replace cocoa butter

Low-calorie fats

Captex 300 Captex 350 Captex 355 (New AKomed range) Neobee M-5 MCT Oil

Medium chain triglycerides (C6:0 to C12:0, mostly C8:0 and C10:0)

Karlshamns, Sweden

Medium chain triglyceride — MCT. Made from glycerine and caprylic/capric fatty acids Acronym for — Short And Long Chain Acid Triglyceride Molecules (Short chain — acetic, propionic and/or butyric; Long chain — predominantly stearic)

Stepan Company, NJ, USA

8.3 kcal/g. Delivers quick energy Lower tendency to form depot fat 7% in oatmeal cookies 8.3 kcal/g. Delivers quick energy

Nabisco Foods Group, NJ, USA/Pfizer Inc., Food Science Group, New York, NY, USA

5 kcal/g. Designed to replace primarily confectionery fats

0.25–0.5% Fat replacer and flavoring system Contains 13.5% fat Availability depends on FDA approval for Olestra

Low-calorie fats

Low-calorie fats

Salatrim

Fat extenders

Dried Cream Extract

Concentrated milk fat flavor encapsulated with maltodextrin

Cumberland Packing Corp., USA

Fat extenders

Olestrin

Blend of sucrose polyesters, triglycerides and dextrins

Reach Associates, Inc. NJ, USA

Fat extenders

Prime-O-Lean Prime-O-Lean Vit (or Algesteren)

P-O-L — Mix of canola oil, beef proteins, tapioca flour, and water P-O-L Vit — Mix of water, partially hydrogenated canola oil, wheat gluten, tapioca starch, egg white, sodium alginate, lecithin and flavor

The Bon Dente Company, Washington, D.C./MD, USA (Licensed to -) Lipidyne Inc., Washington, D.C./MD, USA, Devro Inc., NJ, USA

©1996 CRC Press LLC

< 25% Replacement for animal fat No longer available from Devro Inc.

Chocolate, confectionery products, (salad dressing, mayonnaise, baked goods, frozen dinners, margarine, spreads, milk, cheese) Primarily as a replacement for liquid vegetable oils in products Margarine, mayonnaise, salad oils, processed cheese, baked goods and frying foods (Below 325∞F) Chocolate coatings, confectionery products, baked goods. Patent applications include — natural and processed cheese, cultured products, and ice cream Dairy products

Cakes, muffins, biscuits, crackers, frozen desserts, yogurt and salad oil Ground meat products — Sausages, hamburgers, processed meat

Group

Trade Name/ Common Name

Fat extenders

VanSystem PC-50 VanSystem CF-50

Fat extenders

Veri-Lo 100

Fat extenders

Veri-Lo 200

Synthetic fat substitutes

Synthetic fat substitutes

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

PC-50 — Partially hydrogenated soybean and cotton seed oils, mono and diglycerides, BHT, citric acid CF-50 — PC + Lecithin O/w emulsion containing: water, soya oil, modified starch, agar, mono- and diglycerides, polysorbate 60, potassium sorbate, phosphoric acid O/w emulsion containing ingredients as for Veri-Lo 100 except that soya oil is replaced by anhydrous milk fat and polysorbate 60 is replaced by polysorbate 80

Van den Bergh, Food Ingredients Group, IL, USA

AGFAPs

Alkyl glycoside fatty acid polyesters

Alkoxylated alkyl glycosides esterified with fatty acids

Alkoxylated alkyl glycosides esterified with fatty acids, e.g., ethyl glucoside tetraacetate, ethyl maltoside polyoleate

©1996 CRC Press LLC

Pfizer Inc., Food Science Group, New York, NY, USA

Concentration Used/ Special Features

Applications Bakery products, bakery ingredients

Replaces fat on 1: 1 basis, giving 67–75% fat reduction (refrigerated storage) o/w emulsion; 35% solids, 33% fat Discontinued production Replaces fat on 1: 1 basis, giving 67–75% fat reduction (Refrigerated storage) o/w emulsion; 27% solids, 25% fat Discontinued production

Salad dressings, mayonnaise, sandwich sauces

Curtice Burns Foods Inc., NY, USA

Non-digestible Non-caloric

Procter & Gamble Company, OH, USA

Non-digestible Non-caloric

Shortenings, margarines, butter, salad, cooking and frying oils, mayonnaise, salad dressings, confectionery coatings Baked goods, shortenings, spreads, frying oils, meat products, confectionery products

Pfizer Inc., Food Science Group, New York, NY, USA

Dairy products

Synthetic fat substitutes

Carboxy/carboxylate esters

Carboxy/carboxylate esters, e.g., didecyl stearoyloxymethanedicarboxylate

Nabisco Brands Inc. NJ, USA

Low- to non-digestible Low- to non-caloric

Synthetic fat substitutes

Colestra

Food Ingredients and Innovations, MA, USA

Non-digestible Non-caloric

Synthetic fat substitutes

DDM

As for Olestra (-mixture of hexa- to octa-ester of sucrose with natural occurring fatty acids (C8 to C22)), but designed especially to mimic milk fat Dialkyl dihexadecymalonate — fatty alcohol ester of malonic and alkylmalonic acids

Frito-Lay Inc., TX, USA

Non-digestible Non-caloric

Synthetic fat substitutes

Dialkyl glycerol ethers Glycerol monoester diethers

Swift and Co., IL, USA

Non-digestible Non-caloric

Synthetic fat substitutes

Diol lipids

Dialkyl glycerol ethers, glycerol monoester diethers (Examples of alkyl glyceryl ethers) Diol lipids — ethylene glycol esters of fatty acids and derivatives (e.g., long chain diol diesters)

Nabisco Brands Inc. NJ, USA

Partially digestible; 0.5–8.5 kcal/g.

Synthetic fat substitutes

EEEP

EEEPs — Esterified epoxide extended polyols EPGs — Esterified propoxylated glycerols

Arco Chemical Technology Inc., PA, USA

Low- to non-digestible Low- to non-caloric

EPG

©1996 CRC Press LLC

Filled creams, ice cream, milk, cheese products, wafers, coconut oil mimetic, butter icing, frozen desserts, puddings, margarine, meat products Primarily dairy applications

Low mol. wt. DDM — Cold processing, e.g., mayonnaise, margarine High mol. wt. DDM — Synthetic frying oils

Frozen desserts, puddings, margarine substitutes, bakery goods, mayonnaise, salad dressing, cheese spreads, frying oil, meat products, cocoa butter replacer EPG — Stable for frying and baking, salad dressings, mayonnaise, ice cream, toppings, sauces

Group

Trade Name/ Common Name

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Synthetic fat substitutes

Ether-bridged polyesters

Ether-bridged polyesters (two multibasic acids joined by ether linkage)

Nabisco Brands Inc. NJ, USA

Low- to non-digestible Low- to non-caloric

Synthetic fat substitutes

Ethyl esters

Dow Chemical Inc., MI, USA

Partially digestible

Synthetic fat substitutes Synthetic fat substitutes

Glycerol dialkyl ethers

Ethyl esters of fatty acid dimers and trimers; polybasic acids Glycerol dialkyl ethers

Swift and Co., IL, USA (part of Beatrice Co., IL, USA) The Procter & Gamble Company, OH, USA

Non-digestible Non-caloric Non-digestible Non-caloric*

Arco Chemical Technology Inc., PA, USA

Non-digestible Non-caloric

Olestra (sucrose polyester)

Mixture of hexa- to octaesters of sucrose with naturally occurring fatty acids (C8 to C22)

Synthetic fat substitutes

PEP

Synthetic fat substitutes

Polyhydroxyl esters Polyhydroxyl ethers

Synthetic fat substitutes

Polyorganosiloxanes

PEPs — Partially esterified polysaccharides; also partially esterified oligosaccharides Total substituted long chain esters and ethers of polyhydroxyl compds (sucrose, triglycerol, polyethylenglycol) Polymerised organic derivatives of silica. e.g., Polydimethylsiloxane (PDMS)

Compatible with any vegetable/animal fat. For use in margarine, mayonnaise, baked goods Frozen desserts

Margarine, ice cream, cheese, salad dressing, baked products, processed meats, confectionery products, snacks, cooking/frying oil PEPs — salad oils, cooking oils, margarine, butter blends, mayonnaise, shortening, etc.

Partially digestible

Dow Corning Corporation, MI, USA

Non-digestible Non-caloric

* Since completing this manuscript, the U.S. FDA announced on January 24, 1996 their approval for the use of olestra in selected savory snacks.

©1996 CRC Press LLC

Applications

PDMS — frying media Polyorganosiloxanes — frying, salad dressings

Synthetic fat substitutes

Polyoxyalkylene Polyalklene oxide

Polyoxyalkylene Polyalklene oxide

Dow Chemical Inc., MI, USA

Non-digestible Non-caloric

Synthetic fat substitutes

Polysaccharide polyesters

Curtice Burns Foods Inc., NY, USA

Non-digestible Non-caloric

Synthetic fat substitutes

Polyvinyl ester

E.g. raffinose, sorbitol, trehalose and stachyose polyesters Polyvinyl oleate

Nabisco Brands Inc., NJ, USA

Low- to non-digestible Low- to non-caloric

Synthetic fat substitutes

Propylene glycol diesters

The Procter & Gamble Company, OH, USA

Low- to non-digestible Low- to non-caloric

Synthetic fat substitutes

TATCA

Best Foods (Division of CPC International, NJ, USA)

Non-digestible Non-caloric

Mayonnaise, margarine, egg frying, cake baking

Synthetic fat substitutes

THMA

Propylene glycol diesters of medium and long chain saturated fatty acids Trialkoxytricarballate — tricarballic acid esterified with fatty alcohols Tris-hydroxymethyl alkene esters

Nabisco Brands Inc., NJ,, USA

Partially digestible; 0.5–6.0 kcal/g.

Frozen desserts, puddings, margarine, salad dressing, dairy and non-dairy cheese spreads, frying oil, meat products, bakery products, cocoa butter replacer

Synthetic fat substitutes

Trialkoxyglyceryl ethers

Trialkoxyglyceryl ethers (Example of alkyl glyceryl ethers)

CPC International, NJ, USA

Non-digestible Non-caloric

©1996 CRC Press LLC

Cooking/salad/frying oil, shortening, cakes, ice cream, confectionery, mayonnaise, margarine, potato chips, snack food Deep fat frying, salad dressings, non-dairy sour cream Frying oils, baked goods, frozen desserts, margarine, salad dressing, meats, frostings and fillings Chocolate flavored products

Group Combination systems

Trade Name/ Common Name Atmos 378K

Atmos 659K

Chemical Name/ Composition 378K — Mono and diglycerides, polysorbate 60, sodium stearoyl lactylate 659K — Mono and diglycerides and propylene glycol mixed esters Mono and diglycerides, sorbitan monostearate, polysorbate 60 Carrageenan, dairy protein

Developer/ Manufacturer/ Supplier

Applications

Witco Corporation, (Chem. division) New York, NY, USA

Bakery products and bakery ingredients, sauces, confectionery, dairy products, desserts, salad dressings, spreads

Witco Corporation, (Chem. division) New York, NY, USA Sanofi Bio-Industries, Paris, France California Raisin Advisory Board, CA, USA

Bakery products

Combination systems

Atmos 758K

Combination systems Combination systems

Bindtex California Raisin Paste

59.3% soluble noncellulose polysaccharides, 30.7% cellulose, 10% insoluble noncellulose Polysaccharides.

Combination systems

CarraFat

Water, carrageenan, salt, flavoring

Carrageenan Marketing Corporation, CA, USA

Combination systems

Dariloid

Xanthan gum/galactomannan blends

Kelco Unit of Monsanto Co., CA, USA

Combination systems

Dried Plum (Prune) Powder

Dried Plum (Prune) Powder

Vacu-Dry Co., CA, USA

©1996 CRC Press LLC

Concentration Used/ Special Features

Low water activity of 0.51–0.62 Made by extruding raisins through a fine mesh screen. A mild heat treatment keeps paste pliable and soft during storage Emulsified solid gel (ca. 90% water); 4 weeks shelf-life under refrigerated conditions

Developed for low-fat meat applications Dairy, confectionery, snacks, bakery, cereals

Meat, fish and poultry products

Ice cream, frozen desserts, dairy products, dry mixes, sauces, dressings, dips Bakery products, confectionery products

Combination systems

Dried Plum Puree

Composition of dried plum puree: 45% — dried plums; 55% — various combinations of water, corn syrup &/other fruits/fruit pectins

Combination systems

EC-25

Combination systems

Enrich 301

Combination systems

Fat Replacer 785 Fat Replacer 786

Combination systems

Fat-Tastic

Propylene glycol, mono and diglycerides, partially hydrogenated soybean oil lecithin Blend of cultured non-fat dry milks derived from a multi fermentation process with sugar 785 — Combination of carbohydrates (maltodextrins and vegetable fiber), stabilizers (carrageenan,CMC) and flavor 786 — 785 + Egg albumen Carrageenan, water, salt, and flavors; pre-hydrated and gelled

©1996 CRC Press LLC

Suppliers:Caravan Prodts. Co. Inc./Henry and Henry, Inc./Mariani Packing Co. Inc./Natural Fd Techn. Inc./The Plumlife Co. Inc./Skjodt-Barrett Fds Inc./Sokol and Co. Inc./Stapleton-Spence Packing Co./Sunsweet Growers Inc./SYSCO Corp./Valley View Packing Van den Bergh, Food Ingredients Group, IL, USA

Fat replaced with half weight or volume of dried plum puree

Quest International Flavours and Food Ingredients Co., CA, USA

1.5–2.5%

Ice cream, ice milk, frozen yogurt, frozen dessert premixes, soft serve dairy mixes Meat products — burgers, sausages, liver pate

5–15% Also available in dry powder form and based on modified starch instead of carrageenan

Meat products e.g., — ground beef, pork sausages Non-carrageenan version — hot dogs, bologna

Bakery products

Vaessen-Schoemaker Chemische Industrie B.V., Holland

Wixon/Fontarome, WI. USA

Bakery products

Group

Trade Name/ Common Name

Combination systems

Gatodan 415

Combination systems Combination systems

Just Like Shortenin’

Combination systems

Kel-Lite * BK Kel-Lite * CM

Combination systems Combination systems

LeanMaker

K-Blazer

Matricks

©1996 CRC Press LLC

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Blend of distilled monoglycerides and alphatending emulsifiers Dried plums, apples, water

Grindsted (now Danisco Ingredients), Brabrand, Denmark The PlumLife Co., CN, USA

Blend of whey, propylene glycol monoester, modified starch, oat fiber, mono- and diglycerides, polysorbate 60, sodium caseinate, diacetyl tartaric acid ester, dipotassuim phosphate, silicon dioxide and xanthan gum BK = Cellulose gel, sodium stearoyl lactylate, xanthan gum, gum arabic, dextrin, lecithin, mono- and diglycerides CM = same as BK but without cellulose gel Oat bran, flavorings, seasonings Water, maltodextrin, sodium alginate

Kraft Foods Ingredients, TN, USA (Division of Kraft General Foods, IL, USA)

Kelco Unit of Monsanto Co., CA, USA

Heller Seasonings and Ingredients, IL, USA Lifewise Ingredients Inc., IL, USA

Concentration Used/ Special Features (Readily disperses in water)

Applications Low-fat batter systems, muffins Bakery products, sauces Shortening replacement system for bakery products e.g., — breads, rolls, cakes, brownies and other confectionery products Also available in Europe without propylene glycol and polysorbate 60.

Shortening replacement systems

Breads, rolls, cakes, brownies, cookies, crackers

Meat applications Meat, fish and poultry products

Combination systems

MichaeLite range

E.g., 420 — buttermilk powder, maltodextrin, veg. gums, egg white powder, cellulose, mono- and diglycerides, polysorbate 80 and dextrose

David Michael and Co. Inc., PA, USA

420 — 3% in dairy desserts

Combination systems

N-Flate

National Starch & Chemical Company, Food Product Division, NJ, USA

6–8% Developed for cake mixes to increase air incorporation

Combination systems

N-Lite F

Novagel RCN-10 Novagel RCN-15

National Starch & Chemical Company, Food Product Division, NJ, USA FMC Corporation, PA, USA

Air entrapment system

Combination systems

Mono- and diglycerides, polyglycerol ester, modified starch, guar gum, non-fat dry milk Modified starch, guar gum, nonfat dry milk, polyglycerol monoester RCN-10 = 90% MCC + 10% guar gum RCN-15 = 85% MCC + 15% guar gum

Combination systems

Nu-Rice

Rice extract, modified proteins and carbohydrates

Ribus Inc., USA

©1996 CRC Press LLC

0.5–5.0% Need moderate shear to disperse

420 — dairy desserts 421 — frostings for cakes and other bakery products 458 — puddings, cake mixes, fillings and hamburgers 819 — shortening replacement Bakery products, bakery ingredients, cakes, whipped products Icings, fillings, frostings, frozen desserts and dry mixes RCN-10 — Frozen desserts, processed cheese, meat products RCN-15 — salad dressings, icings, frostings, gravies Fat free cake, brownies, chocolate frosting, compound coatings, sandwich cookie cream and cake fillings

Group

Trade Name/ Common Name

Combination systems

NutriFat NutriFat NutriFat NutriFat

Combination systems

PALs (ALACO)

Combination systems

Pioneer

Combination systems

Prolestra

Combination systems

Prolo 11

Combination systems

Prune Tec

©1996 CRC Press LLC

C PC Instant PC PC Supreme

Chemical Name/ Composition C — Blend of specific hydrolyzed dextrins, derived from wheat, potato, corn and tapioca, and soluble fiber PC — C + series of animal and veg. proteins Instant PC — same as PC but req. no heating PC Supreme — dextrins and protein particles (piezo) Whey protein concentrate, milk protein concentrate, (or other milk proteins), cellulose gel MCC, mono- and diglycerides, cellulose gum, carrageenan Up to 30% sucrose polyester and a mixture of animal and vegetable proteins

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Applications

The NutriFat Co. a division of Reach Associates, Inc. NJ, USA

Frozen desserts, salad oils, mayonnaise, margarine, muffins

New Zealand Milk Products Inc., CA, USA

Sauces, dairy products

Germantown Manufacturing Company, PA, USA Reach Associates, Inc. NJ, USA

Availability depends on FDA approval for olestra

Nonfat milk, whey protein concentrate, calcium caseinate

Kerry Ingredients, WI, USA

Thermally stable and able to withstand HTST processing

Dried plum paste

California Prune Board, CA, USA

For low water activity applications

Ice cream, salad oils, mayonnaise, spreads, sauces, snacks, baked products Prolo 11 — Ice cream, frozen yogurt, shakes, frozen novelties Also Prolo 44 available for bakery applications Bakery and confectionery products

Combination systems

Rhodilean SD

Combination systems

RP Lean I RP Lean II RP Lean III

Combination systems Combination systems

Sherex Enlite

Combination systems

Simplesse Bakery Blend 720

Combination systems

Simplesse Bakery Blend 730

Combination systems

Simplesse D-550

Combination systems

Slimgel 100 Slimgel 100/i Slimgel 200

Simplesse Bakery Blend 710

©1996 CRC Press LLC

Tricalcium phosphate, Quaker Oatrim, (Rhodigelbrand) xanthan gum I = Quaker Oatrim, iota carrageenan II = Quaker Oatrim, Quaker oat bran, corn syrup solids III = Quaker Oatrim, kappa carrageenan Emulsifier/stabilizer blend Blend of whey protein concentrate, monoglycerides, and sodium stearoyl lactylate Blend of whey protein concentrate, propylene glycol monoesters, distilled monglycerides, and sodium stearoyl lactylate Blend of whey protein concentrates, mono- and diglycerides, lactic acid ester of mono- and diglycerides and lecithin Blend of whey protein concentrate (D-500) and hydrolyzed oat flour 100 — Guar gum, gelatin 100/i — Cold soluble gelatin with guar gum, pectin, maltodextrin 200 — Gelatin, locust bean gum

Rhone-Poulenc Food Ingredients, NJ, USA

Cold water soluble

Oil-free salad dressings

Rhone-Poulenc Food Ingredients, NJ, USA

(III — especially useful where maintaining the appearance of fat is important)

Quest International Bioproducts, CA, USA The NutraSweet Company, IL, USA

Stabilizes air cells in low-fat ice cream products Contains 40% protein

I and II — Sauces, coarsely ground reduced-fat meat products to be stored frozen, fish and poultry products III — Meat, fish and poultry products Low- or no-fat frozen desserts, ice cream Muffins, sweet dough

The NutraSweet Company, IL, USA

Contains 35% protein

Cakes

The NutraSweet Company, IL, USA

Contains 48% protein, 9% fat

Frostings, pastry doughs, cookies

The NutraSweet Company, IL, USA

Contains 34% protein

PB Gelatins (a division of — Tessenderlo Chemie, Vilvoorde, Belgium)

0.6–2.5%

Spreads, butter creams, salad dressings, sauces, pate, frankfurters, sausages, ice cream, dairy creams, cheese, yogurt, baked products

Group

Trade Name/ Common Name

Combination systems

Solex

Combination systems

Superbase

Combination systems

Supercreme C Supercreme SD

Combination systems

Tandem

Combination systems

Ticaloid No Fat 102 range

Combination systems

Ultra-Freeze 400 Ultra-Freeze 500

©1996 CRC Press LLC

Chemical Name/ Composition

Developer/ Manufacturer/ Supplier

Concentration Used/ Special Features

Applications

A stabilizer/emulsifier system which will work synergistically with Simplesse Hydrolyzed rice starch, modified starch, whey protein concentrate and xanthan gum and 0.73% fat

Germantown Manufacturing Company, PA, USA

0.9–1.2%

Frozen desserts from ice cream to frozen yogurts

Exelcon, WI, USA/Sanofi Bio-Industries, Paris, France

Dissolve in hot or cold water. Resistant to high temp., high shear, low pH and freezethaw cycles

Cultured cottage cheese, gelatin, xanthan gum, carrageenan, locust bean gum, flavoring, propylene glycol Mono and diglycerides, polysorbate 60

Commercial Creamery Co. WA, USA

Fat replacer and flavor system C — 94% moisture system, short shelf-life SD — Dry blend

Primarily: sauces, gravies, dips Also: puddings, pour/spoonable dressings, soups, etc. Bakery products, dairy products, meat, fish and poultry products, salad dressings, soups

Blends of hydrocolloids each designed for a particular food application — include: gum arabic, alginate, starch, pectin, carageenan, tragacanth, xanthan, etc. 400 — Modified starch, vegetable protein 500 — Modified starch, soya protein

Witco Corporation, (Chem. division) New York, NY, USA TIC Gums, MD, USA

Gunther Products (division of A.E. Staley Manufacturing Company, IL, USA)

Bakery products and ingredients 0.5–2.0%

Meat products, salad dressing, bakery products, dairy products

Ultra-Freeze 400 — 0.75–1.25% Ultra-Freeze 500 — 0.75–1.5% (500 — can be dry blended and dissolves readily in water)

400 — Frozen yogurt, sherbets, novelties, (Potentially — cheese sauces, cream cheese, frozen waffle mixes and other frozen foods) 500 — Dairy products and substitutes

Combination systems

UltraBake NF

Combination systems

Viscarin carrageenan Viscarin SD 389

©1996 CRC Press LLC

Granular starch, modified vegetable protein, xanthan gum Carrageenan salt, carrageenan, dextrose

A. E. Staley Manufacturing Company, IL, USA FMC Corporation, PA, USA

2–3%

Bakery products

Meat, fish and poultry products, salad dressing