Downloaded by 80.82.77.83 on March 9, 2018 | https://pubs.acs.org Publication Date: May 5, 1996 | doi: 10.1021/bk-1996-0631.pr001
Preface W H O NEEDS C H E M I C A L MARKERS? Chemical markers are compounds that can be used to evaluate quality changes either during processing or during subsequent storage of foods at various conditions. By virtue of their quantitative, predictive, and mimicking features, chemical markers are useful for food scientists and technologists who need to maximize the initial product quality and minimize the deteriorative changes in food during processing and storage. Information about the reaction mechanisms as well as new sensor technologies and other instrumental and analytical methodologies make the use of chemical markers a practical tool in many food applications in-line, on-line, and off-line. Chemistry is involved in every aspect of the food cycle . Of the many chemical reactions in the food cycle, the reactions taking place during processing and storage are particularly important to food chemists. Some reactions, such as the formation of flavor compounds in baking, are desirable. Other reactions, such as lipid oxidation in meats, lead to rancidity and are undesirable. To complicate matters, the desirable and undesirable reactions often represent different stages of the same series of reactions. For example, the Maillard reaction is important for flavor and color generation. However, advanced Maillard reactions could also lead to lysine loss and melanoidin formation or protein cross-linking, as well as other reactions that could cause detrimental nutritional, physiological, and toxicological consequences in certain foods . Understanding the chemical reactions and being able to control the reaction pathway or the extent of the reaction could be critical for optimizing the product quality upon processing and for minimizing detrimental changes during processing and storage. When judiciously used, chemical markers could be useful tools for food scientists because of the following capabilities. 1
2
• Chemical markers provide quantitative information. The ultimate test of a good food product is acceptance by the consumer. This acceptance can be measured by a test panel and quantified to some extent. However, such panel results are often subjective, and objective quantitation using chemical markers is more often desirable. Quantitation by color machine version (Chapter 23) is an example. Depending on the reaction rate constant, quantitative results can be obtained at thermal processing temperature (Chapter 6), at ambient storage temperatures (Chapter 9), and at frozen storage temperatures (Chapter 15). ix Lee and Kim; Chemical Markers for Processed and Stored Foods ACS Symposium Series; American Chemical Society: Washington, DC, 1996.
Downloaded by 80.82.77.83 on March 9, 2018 | https://pubs.acs.org Publication Date: May 5, 1996 | doi: 10.1021/bk-1996-0631.pr001
• Chemical markers have predictive capabilities. Quantitative results derived from chemical marker measurements can be useful for predicting what subsequent reactions will follow once the predictive model is established. Some interesting examples in terms of predicting remaining shelflife are provided in Chapter 10. Moreover, detection of early reaction products or intermediate compounds enables us to predict the extent of subsequent reactions as demonstrated in Chapter 4. • Chemical markers can mimic other processes. Chemical reactions taking place in foods can be used to mimic an entirely different process taking place in the vicinity of the site where the chemical measurements are made. An interesting example is the use of chemical markers to determine lethality within a food particulate where direct temperature measurement is not practical (Chapter 6). It appears that chemical reactions can mimic bacterial destruction, and are potentially useful timetemperature integrators in the continuous thermal processing of foods. In conjunction with the future development of better quantitive chemical markers, the most significant imminent trend in food quality control is the development and application of new sensor technologies and other instrumental methods for the in-line, on-line, and off-line quantitative determination of these chemical markers. This trend is well-illustrated in many chapters in this book (e.g., Chapters 4-7, 9, 12, 15, 16, 18, 19, 21-23). Furthermore, accurate kinetic models are needed to be able to predict remaining shelf-life as well as to optimize product quality that depends on the intricate interplay of various chemical reactions under various processing conditions. Today, people are concerned about the quality of food they consume. The questions are, "What are the important food quality attributes and how can we determine these attributes in-line, on-line, and off-line?" We believe this book is timely and informative in addressing these issues. We hope this book will have wide appeal and will be useful to people working in academia, the food industry, and in governmental agencies dealing with the food manufacturing and service industries, as well as those interested in food quality and its evaluation and controls. Literature Cited 1
Chemistry of the Food Cycle: State of the Art; Taub, I. A.; Karel, M., Eds. Reprinted from J. Chem. Educ. 1984, 61(4), 271-367. 2
Chichester, C. O.; Lee, Tung-Ching. "Effect of Food Processing in the Formation and Destruction of Toxic Constituents of Food." in Impact of
x Lee and Kim; Chemical Markers for Processed and Stored Foods ACS Symposium Series; American Chemical Society: Washington, DC, 1996.
Toxicology in Food Processing; AVI Publishing Company: Westport, Ct, 1981, pp 35-56.
T U N G - C H I N G LEE
Department of Food Science and Center for Advanced Food Technology Cook College Rutgers, The State University of New Jersey P.O. Box 231 New Brunswick, NJ 08903-0231 Downloaded by 80.82.77.83 on March 9, 2018 | https://pubs.acs.org Publication Date: May 5, 1996 | doi: 10.1021/bk-1996-0631.pr001
HIE-JOON KIM
U.S. Army Natick Research Development and Engineering Center Kansas Street Natick, MA 01760-5018 March 28, 1996
xi Lee and Kim; Chemical Markers for Processed and Stored Foods ACS Symposium Series; American Chemical Society: Washington, DC, 1996.
