Page12Another variable, pH, influences the rates of many chemical and enzymic reactions. Extreme pH values are usually required forsevere inhibition of microbial growth or enzymic processes, and these conditions can result in acceleration of acid-or basecatalyzed reactions. In contrast, even a relatively small pH change can cause profound changes in the quality of some foods,forexample,muscleThe composition ofthe product is important since this determines thereactants availablefor chemical transformation.Particularlyimportant from a quality standpoint is therelationship that exists between composition oftherawmaterial and composition ofthefinished product. For example, (a) the manner in which fruits and vegetables are handled postharvest can influence sugar contentand this, in turn, influences the degree of browning obtained during dehydration or deep-fat firying. (b) The manner in whichanimal tissues are handled postmortem influences the extents and rates of glycolysis and ATP degradation, and these in turn caninfluence storage life, water-holding capacity, toughness, flavor, and color. (c) The blending of raw materials may causeunexpected interactions; for example, the rate ofoxidation can be accelerated or inhibited depending on the amount of saltpresent.Another important compositional determinant of reaction rates in foods is water activity (aw). Numerous investigators haveshown aw to strongly influence the rate of enzyme-catalyzed reactions [2], lipid oxidation [16,22], nonenzymic browning [10,16]sucrose hydrolysis [23], chlorophyll degradation [17], anthocyanin degradation [11], and others. As is discussed in Chapter 2,most reactions tend to decrease in rate below an aw corresponding to the range of intermediate moisture foods (0.75-0.85)Oxidation oflipids and associated secondary effects, such as carotenoid decoloration, are exceptions to this rule; that is, thesereactions accelerate at the lower end of the aw scale.More recently,it has become apparent that the glass transition temperature (T.) of food and the corresponding water content(W.) of the food at Tg are causatively related to rates of diffusion-limited events in food. Thus, Tg and W, have relevance to thephysical properties of frozen and dried foods, to conditions appropriate for freeze drying, to physical changes involvingcrystallization, recrystallization, gelatinization, and starch retrogradation, and to those chemical reactions that are diffusion-limited(seeChap.2)In fabricated foods, the composition can be controlled by adding approved chemicals, such as acidulants, chelating agents.flavors, or antioxidants, or by removing undesirable reactants, for example, removing glucose from dehydrated egg albumenComposition of the atmosphere is important mainly with respect to relative humidity and oxygen content, although ethylene andCO2 are also important during storage of living plant foods. Unfortunately, in situations where exclusion of oxygen is desirablethis is almost impossible to achieve completely. The detrimental consequences of a small amount of residual oxygen sometimesbecome apparent during product storage. For example, early formation of a small amount of dehydroascorbic acid (fromoxidationofascorbicacid)canleadtoMaillardbrowningduringstorage.For some products, exposure to light can be detrimental, and it is then appropriate to package the products in light-imperviousmaterial or to control the intensity and wavelengths of light, if possible.Food chemists must be able to integrate information about quality attributes of foods, deteriorative reactions to which foods aresusceptible, and the factors goverming kinds and rates of these deteriorative reactions, in order to solve problems related to foodformulation,processing,and storage stability
Pag e 12 Another variable, pH, influences the rates of many chemical and enzymic reactions. Extreme pH values are usually required for severe inhibition of microbial growth or enzymic processes, and these conditions can result in acceleration of acid- or basecatalyzed reactions. In contrast, even a relatively small pH change can cause profound changes in the quality of some foods, for example, muscle. The composition of the product is important since this determines the reactants available for chemical transformation. Particularly important from a quality standpoint is the relationship that exists between composition of the raw material and composition of the finished product. For example, (a) the manner in which fruits and vegetables are handled postharvest can influence sugar content, and this, in turn, influences the degree of browning obtained during dehydration or deep-fat frying. (b) The manner in which animal tissues are handled postmortem influences the extents and rates of glycolysis and ATP degradation, and these in turn can influence storage life, water-holding capacity, toughness, flavor, and color. (c) The blending of raw materials may cause unexpected interactions; for example, the rate of oxidation can be accelerated or inhibited depending on the amount of salt present. Another important compositional determinant of reaction rates in foods is water activity (aw). Numerous investigators have shown aw to strongly influence the rate of enzyme-catalyzed reactions [2], lipid oxidation [16,22], nonenzymic browning [10,16], sucrose hydrolysis [23], chlorophyll degradation [17], anthocyanin degradation [11], and others. As is discussed in Chapter 2, most reactions tend to decrease in rate below an aw corresponding to the range of intermediate moisture foods (0.75–0.85). Oxidation of lipids and associated secondary effects, such as carotenoid decoloration, are exceptions to this rule; that is, these reactions accelerate at the lower end of the aw scale. More recently, it has become apparent that the glass transition temperature (Tg) of food and the corresponding water content (Wg) of the food at Tg are causatively related to rates of diffusion-limited events in food. Thus, Tg and Wg have relevance to the physical properties of frozen and dried foods, to conditions appropriate for freeze drying, to physical changes involving crystallization, recrystallization, gelatinization, and starch retrogradation, and to those chemical reactions that are diffusion-limited (see Chap. 2). In fabricated foods, the composition can be controlled by adding approved chemicals, such as acidulants, chelating agents, flavors, or antioxidants, or by removing undesirable reactants, for example, removing glucose from dehydrated egg albumen. Composition of the atmosphere is important mainly with respect to relative humidity and oxygen content, although ethylene and CO2 are also important during storage of living plant foods. Unfortunately, in situations where exclusion of oxygen is desirable, this is almost impossible to achieve completely. The detrimental consequences of a small amount of residual oxygen sometimes become apparent during product storage. For example, early formation of a small amount of dehydroascorbic acid (from oxidation of ascorbic acid) can lead to Maillard browning during storage. For some products, exposure to light can be detrimental, and it is then appropriate to package the products in light-impervious material or to control the intensity and wavelengths of light, if possible. Food chemists must be able to integrate information about quality attributes of foods, deteriorative reactions to which foods are susceptible, and the factors governing kinds and rates of these deteriorative reactions, in order to solve problems related to food formulation, processing, and storage stability
Page 131.4 Societal Role of Food ChemistsI.4.I Why Should Food Chemists Become Involved in Societal Issues?Food chemists, for the following reasons, should feel obligated to become involved in societal issues that encompass pertinenttechnologicalaspects(technosocietalissues)·Food chemists have had the privilege ofreceiving a high level ofeducation and ofacquiring special scientific skills, and theseprivileges and skills carry with them a corresponding high level of responsibility.· Activities offood chemists influence adequacy of the food supply, healthfulness of the population, cost offoods, waste creationand disposal, water and energy use, and the nature of food regulations. Because these matters impinge on the general welfare ofthe public, it is reasonable that food chemists should feel a responsibility to have their activities directed to the benefit of societyIffood chemists do not become involved in technosocietal issues, the opinions ofothersscientists from other professions,professional lobbyists,persons in the news media, consumer activists, charlatans, antitechnology zealotswill prevail. Many ofthese individuals are less qualified thanfood chemists to speak on food-related issues,and some areobviously unqualified1.4.2Types of InvolvementThe societal obligations offood chemists includegood job performance,good citizenship,and guarding the ethics ofthe scientificcommunity, but fulfllment of these very necessary roles is not enough. An additional role of great importance, and one that oftengoes unfulfilled by food chemists, is that ofhelping determine how scientific knowledge is interpreted and used by society.Although food chemists and other food scientists should not have the only input to these decisions, they must, in the interest ofwise decision making, have their views heard and considered.Acceptance ofthis position,which is surely indisputable, leadstothe obvious question,What exactly should food chemists do to properly discharge their responsibilities in this regard?"Severalactivities areappropriate.1. Participate in pertinent professional societies.2. Serve on governmental advisory committees, when invited.3.Undertake personal initiatives ofa public service nature.The latter can involve letters to newspapers, journals, legislators,government regulators,company executives,universityadministrators, and others, and speeches before civic groups.The major objectives ofthese efforts are to educate and enlighten the public with respect to food and dietary practices. Thisinvolves improving the public's ability to intelligently evaluate information on these topics. Accomplishing this will not be easybecause a significant portion of the populace has ingrained false notions aboutfood and proper dietary practices, and becausefoodhas,formanyindividuals,connotationsthatextendfarbeyondthechemist'snarrowview.Fortheseindividuals,foodmaybeanintegralpartofreligiouspractice,culturalheritage,ritual,social symbolism,oraroutetophysiological well-beingattitudes that are, for the most part, not conducive to acquiring an ability to appraise foods and dietary practices in asound, scientific manner.One of the most contentious food issues, and one that has eluded appraisal by the
Pag e 13 1.4 Societal Role of Food Chemists 1.4.1 Why Should Food Chemists Become Involved in Societal Issues? Food chemists, for the following reasons, should feel obligated to become involved in societal issues that encompass pertinent technological aspects (technosocietal issues). • Food chemists have had the privilege of receiving a high level of education and of acquiring special scientific skills, and these privileges and skills carry with them a corresponding high level of responsibility. • Activities of food chemists influence adequacy of the food supply, healthfulness of the population, cost of foods, waste creation and disposal, water and energy use, and the nature of food regulations. Because these matters impinge on the general welfare of the public, it is reasonable that food chemists should feel a responsibility to have their activities directed to the benefit of society. • If food chemists do not become involved in technosocietal issues, the opinions of others—scientists from other professions, professional lobbyists, persons in the news media, consumer activists, charlatans, antitechnology zealots—will prevail. Many of these individuals are less qualified than food chemists to speak on food-related issues, and some are obviously unqualified. 1.4.2 Types of Involvement The societal obligations of food chemists include good job performance, good citizenship, and guarding the ethics of the scientific community, but fulfillment of these very necessary roles is not enough. An additional role of great importance, and one that often goes unfulfilled by food chemists, is that of helping determine how scientific knowledge is interpreted and used by society. Although food chemists and other food scientists should not have the only input to these decisions, they must, in the interest of wise decision making, have their views heard and considered. Acceptance of this position, which is surely indisputable, leads to the obvious question, “What exactly should food chemists do to properly discharge their responsibilities in this regard?” Several activities are appropriate. 1. Participate in pertinent professional societies. 2. Serve on governmental advisory committees, when invited. 3. Undertake personal initiatives of a public service nature. The latter can involve letters to newspapers, journals, legislators, government regulators, company executives, university administrators, and others, and speeches before civic groups. The major objectives of these efforts are to educate and enlighten the public with respect to food and dietary practices. This involves improving the public's ability to intelligently evaluate information on these topics. Accomplishing this will not be easy because a significant portion of the populace has ingrained false notions about food and proper dietary practices, and because food has, for many individuals, connotations that extend far beyond the chemist's narrow view. For these individuals, food may be an integral part of religious practice, cultural heritage, ritual, social symbolism, or a route to physiological wellbeing—attitudes that are, for the most part, not conducive to acquiring an ability to appraise foods and dietary practices in a sound, scientific manner. One of the most contentious food issues, and one that has eluded appraisal by the
Page14public in a sound, scientific manner, is the use of chemicals to modify foods.“Chemophobia,the fear of chemicals, has afflictedasignificantportion ofthepopulace,causingfoodadditives,inthemindsofmany,torepresenthazardsinconsistentwithfactOne can find, with disturbing ease, articles in the popular literature whose authors claim the American food supply is sufficientlyladen with poisons to render it unwholesome at best, and life-threatening at worst. Truly shocking, they say, is the manner inwhich greedy industrialists poison our foods for profit while an ineffectual Food and Drug Administration watches with placidunconcern. Should authors holding this viewpoint be believed? It is advisable to apply the following criteria when evaluating thevalidity of any journalistic account dealing with issues of this kind.·Credibility ofthe author.Is the author,by virtue offormal education,experience, and acceptance byreputable scientistsqualified to write on the subject? The writer should, to be considered authoritative, have been a frequent publisher of articles inrespected scientific journals, especially those requiring peer review. If the writer has contributed only to the popular literature,particularly in the form of articles with sensational titles and catch"phrases, this is cause to exercise special care in assessingwhether the presentation is scholarly and reliable.·Appropriateness of literature citations. A lack of literature citations does not constitute proof of irresponsible or unreliablewriting, but it should provoke a feeling ofmoderate skepticism in the reader. In trustworthy publications, literature citations willalmost invariably be present and will direct the reader to highly regarded scientific publications. When“popular"articlesconstitute the bulk of the literature citations, the author's views should be regarded with suspicion.· Credibility of the publisher. Is the publisher of the article, book, or magazine regarded by reputable scientists as a consistentpublisher of high-quality scientific materials? If not, an extra measure of caution is appropriate when considering the data.If information in poison-pen types of publications are evaluated by rational individuals on the basis of the preceding criteria, suchinformation will be dismissed as unreliable. However, even if these criteria are followed, disagreement about the safety of foodsstill occurs. The great majority of knowledgeable individuals support the view that our food supply is acceptably safe andnutritious and that legally sanctioned food additives pose no unwarranted risks [7,13,15,19,24-26]. However, a relatively smallgroup of knowledgeable individuals believes that our food supply is unnecessarily hazardous, particularly with regard to some ofthe legally sanctioned food additives, and this view is most vigorously represented by Michael Jacobson and his Center forScience in the Public Interest. This serious dichotomy of opinion cannot be resolved here, but information provided in Chapter13 wil help undecided individuals arrive at a soundly based personal perspective on food additives, contaminants in foods, andfood safetyIn summary,scientists have greater obligations to society than do individuals withoutformal scientific education. Scientists areexpected to generate knowledge in a productive, ethical manner, but this is not enough. They should also accept theresponsibility of ensuring that scientific knowledge is used in a manner that will yield the greatest benefit to society.Fulfllment ofthis obligation requires that scientists not only strive for excellence and conformance to high ethical standards in their day-to-dayprofessionalactivities,butthattheyalsodevelopadeep-seatedconcernforthewell-beingand scientificenlightenmentofthepublic
Pag e 14 public in a sound, scientific manner, is the use of chemicals to modify foods. “Chemophobia,” the fear of chemicals, has afflicted a significant portion of the populace, causing food additives, in the minds of many, to represent hazards inconsistent with fact. One can find, with disturbing ease, articles in the popular literature whose authors claim the American food supply is sufficiently laden with poisons to render it unwholesome at best, and life-threatening at worst. Truly shocking, they say, is the manner in which greedy industrialists poison our foods for profit while an ineffectual Food and Drug Administration watches with placid unconcern. Should authors holding this viewpoint be believed? It is advisable to apply the following criteria when evaluating the validity of any journalistic account dealing with issues of this kind. • Credibility of the author. Is the author, by virtue of formal education, experience, and acceptance by reputable scientists, qualified to write on the subject? The writer should, to be considered authoritative, have been a frequent publisher of articles in respected scientific journals, especially those requiring peer review. If the writer has contributed only to the popular literature, particularly in the form of articles with sensational titles and “catch” phrases, this is cause to exercise special care in assessing whether the presentation is scholarly and reliable. • Appropriateness of literature citations. A lack of literature citations does not constitute proof of irresponsible or unreliable writing, but it should provoke a feeling of moderate skepticism in the reader. In trustworthy publications, literature citations will almost invariably be present and will direct the reader to highly regarded scientific publications. When “popular” articles constitute the bulk of the literature citations, the author's views should be regarded with suspicion. • Credibility of the publisher. Is the publisher of the article, book, or magazine regarded by reputable scientists as a consistent publisher of high-quality scientific materials? If not, an extra measure of caution is appropriate when considering the data. If information in poison-pen types of publications are evaluated by rational individuals on the basis of the preceding criteria, such information will be dismissed as unreliable. However, even if these criteria are followed, disagreement about the safety of foods still occurs. The great majority of knowledgeable individuals support the view that our food supply is acceptably safe and nutritious and that legally sanctioned food additives pose no unwarranted risks [7,13,15,19,24–26]. However, a relatively small group of knowledgeable individuals believes that our food supply is unnecessarily hazardous, particularly with regard to some of the legally sanctioned food additives, and this view is most vigorously represented by Michael Jacobson and his Center for Science in the Public Interest. This serious dichotomy of opinion cannot be resolved here, but information provided in Chapter 13 will help undecided individuals arrive at a soundly based personal perspective on food additives, contaminants in foods, and food safety. In summary, scientists have greater obligations to society than do individuals without formal scientific education. Scientists are expected to generate knowledge in a productive, ethical manner, but this is not enough. They should also accept the responsibility of ensuring that scientific knowledge is used in a manner that will yield the greatest benefit to society. Fulfillment of this obligation requires that scientists not only strive for excellence and conformance to high ethical standards in their day-to-day professional activities, but that they also develop a deep-seated concern for the well-being and scientific enlightenment of the public
Page15References1. Accum, F. (1966). A Treatise on Adulteration of Food, and Culinary Poisons, 1920, Facsimile reprint by MallinckrodtChemical Works, St. Louis, MO.2. Acker, L. W. (1969). Water activity and enzyme activity. Food Technol. 23(10):1257-1270.3. Anonymous (1831). Death in the Pot. Cited by Filby, 1934 (Ref. 12).4.Beaumont, W.(1833).Experiments and Observations of the Gastric Juice and the Physiology of Digestion, F.P.Allen, Plattsburgh, NY.5.Browne, C.A. (1944).A Source Book of Agricultural Chemistry.Chronica Botanica Co., Waltham, MA.6. Chevreul, M.E. (1824).Considerations generales sur l'analyse organique et sur ses applications.Cited by Filby,1934 (Ref.12),7. Clydesdale, F. M., and F. J. Francis (1977). Food, Nutrition and You, Prentice-Hal, Englewood Cliffs, NJ8. Davy, H. (1813). Elements of Agricultural Chemistry, in a Course of Lectures for the Board of Agriculture, Longman,Hurst, Rees, Orme and Brown, London, Cited by Browne, 1944 (Ref. 5).9. Davy, H. (1936). Elements of Agricultural Chemistry, 5th ed, Longman, Rees, Orme, Brown, Green and LongmanLondon,10. Eichner,K., and M. Karel (1972).The influence of water content and water activity on the sugar-amino browning reactionin model systems under various conditions.J.Agric.Food Chem.20(2):218-223.11.Erlandson,J. A, and R.E. Wrolstad (1972).Degradation of anthocyanins at limited water concentration J. Food Sci37(4):592-595.12. Filby, F. A. (1934). A History of Food Adulteration and Analysis, George Allen and Unwin, London.13. Hal, R. L. (1982). Food additives, in Food and People (D. Kirk and I. K. Eliason, eds.), Boyd and Fraser, SanFrancisco, pp.148-156.14. Ihde, A. J. (1964). The Development of Modern Chemistry, Harper and Row, New York15. Jukes, T. H. (1978). How safe is our food supply? Arch. Intern. Med. 138:772-77416. Labuza, T. P., S. R. Tannenbaum, and M. Karel (1970). Water content and stability of low-moisture and intermediate-moisture foods.Food Techol. 24(5):543-55017. LaJollo, F., S. R Tannenbaum, and T. P. Labuza (1971). Reaction at limited water concentration. 2. Chlorophylldegradation. J. Food Sci. 36(6):850-853.18. Liebig, J. Von (1847). Researches on the Chemistry of Food, edited from the author's manuscript by William Gregory,Londson, Taylor and Walton, London. Cited by Browne, 1944 (Ref. 5)19. Mayer, J. (1975). A Diet for Living, David McKay, Inc., New York.20. McCollum, E. V. (1959). The history of nutrition. World Rev. Nutr. Diet. 1:1-27.21. McWeeny, D. J. (1968). Reactions in food systems: Negative temperature coefficients and other abnormal temperatureeffects.J.Food Technol.3:15-30.22. Quast, D. G., and M. Karel (1972). Effects of environmental factors on the oxidation of potato chips. J. Food Sci.37(4):584-588.23. Schoebel, T., S. R. Tannenbaum, and T. P. Labuza (1969). Reaction at limited water concentration. 1. Sucrose hydrolysisJ.Food Sci.34(4):324-329
Pag e 15 References 1. Accum, F. (1966). A Treatise on Adulteration of Food, and Culinary Poisons, 1920, Facsimile reprint by Mallinckrodt Chemical Works, St. Louis, MO. 2. Acker, L. W. (1969). Water activity and enzyme activity. Food Technol. 23(10):1257–1270. 3. Anonymous (1831). Death in the Pot. Cited by Filby, 1934 (Ref. 12). 4. Beaumont, W. (1833). Experiments and Observations of the Gastric Juice and the Physiology of Digestion, F. P. Allen, Plattsburgh, NY. 5. Browne, C. A. (1944). A Source Book of Agricultural Chemistry. Chronica Botanica Co., Waltham, MA. 6. Chevreul, M. E. (1824). Considérations générales sur l'analyse organique et sur ses applications. Cited by Filby, 1934 (Ref. 12). 7. Clydesdale, F. M., and F. J. Francis (1977). Food, Nutrition and You, Prentice-Hall, Englewood Cliffs, NJ. 8. Davy, H. (1813). Elements of Agricultural Chemistry, in a Course of Lectures for the Board of Agriculture, Longman, Hurst, Rees, Orme and Brown, London, Cited by Browne, 1944 (Ref. 5). 9. Davy, H. (1936). Elements of Agricultural Chemistry, 5th ed., Longman, Rees, Orme, Brown, Green and Longman, London. 10. Eichner, K., and M. Karel (1972). The influence of water content and water activity on the sugar-amino browning reaction in model systems under various conditions. J. Agric. Food Chem. 20(2):218–223. 11. Erlandson, J. A., and R. E. Wrolstad (1972). Degradation of anthocyanins at limited water concentration. J. Food Sci. 37(4):592–595. 12. Filby, F. A. (1934). A History of Food Adulteration and Analysis, George Allen and Unwin, London. 13. Hall, R. L. (1982). Food additives, in Food and People (D. Kirk and I. K. Eliason, eds.), Boyd and Fraser, San Francisco, pp. 148–156. 14. Ihde, A. J. (1964). The Development of Modern Chemistry, Harper and Row, New York. 15. Jukes, T. H. (1978). How safe is our food supply? Arch. Intern. Med. 138:772–774. 16. Labuza, T. P., S. R. Tannenbaum, and M. Karel (1970). Water content and stability of low-moisture and intermediatemoisture foods. Food Techol. 24(5):543–550. 17. LaJollo, F., S. R. Tannenbaum, and T. P. Labuza (1971). Reaction at limited water concentration. 2. Chlorophyll degradation. J. Food Sci. 36(6):850–853. 18. Liebig, J. Von (1847). Researches on the Chemistry of Food, edited from the author's manuscript by William Gregory; Londson, Taylor and Walton, London. Cited by Browne, 1944 (Ref. 5). 19. Mayer, J. (1975). A Diet for Living, David McKay, Inc., New York. 20. McCollum, E. V. (1959). The history of nutrition. World Rev. Nutr. Diet. 1:1–27. 21. McWeeny, D. J. (1968). Reactions in food systems: Negative temperature coefficients and other abnormal temperature effects. J. Food Technol. 3:15–30. 22. Quast, D. G., and M. Karel (1972). Effects of environmental factors on the oxidation of potato chips. J. Food Sci. 37(4):584–588. 23. Schoebel, T., S. R. Tannenbaum, and T. P. Labuza (1969). Reaction at limited water concentration. 1. Sucrose hydrolysis. J. Food Sci. 34(4):324–329
24. Stare, F. J., and E. M. Whelan (1978).Eat OK-Feel OK, Christopher Publishing House, North Quincy, MA25.Taylor, R.J. (1980).Food Additives, John Wiley & Sons, New York.26. Whelan, E. M. (1993). Toxic Terror, Prometheus Books, Buffalo, NY
24. Stare, F. J., and E. M. Whelan (1978). Eat OK—Feel OK, Christopher Publishing House, North Quincy, MA. 25. Taylor, R. J. (1980). Food Additives, John Wiley & Sons, New York. 26. Whelan, E. M. (1993). Toxic Terror, Prometheus Books, Buffalo, NY