Dramatic changes in the attitudes toward human nutrition have taken place dur ing the past decade. Food-related and medical professionals as well as consumers are now, more than ever before, aware of and concerned about diet, nutrition, and the beneficial and deleterious effects of food processing upon nutrients. The old saying "We are what we eat" is still relevant. Nutritious food will contribute greatly to consumers' good health and ultimately reduce medical bills. Food processing is essential to maintaining our food reserves from one harvest to another, thus letting us serve our daily meals regularly. If food processing is defined as including all treatments of foodstuffs from harvest to consumption, then more than 95% of our food may be considered as processed. In most cases, food processing and storage cause some reduction in the nutritional value of foods. Advances in food science and food technology have resulted in an increase in nu trient retention after processing. In addition, today's consumer better understands how to avoid excessive nutrient losses during food preparation. The information presented in this completely revised reference and textbook will help the reader to understand better the relationship between food processing and nutrient retention. The authors' scholarly contributions are greatly appreciated.

A variety of processing methods are used to make foods edible; to pennit storage; to alter texture and flavor; to sterilize and pasteurize food; and to destroy microorganisms and other toxins. These methods include baking, broiling, cooking, freezing, frying, and roasting. Many such efforts have both beneficial and harmful effects. It is a paradox of nature that the processing of foods can improve nutrition, quality, safety, and taste, and yet occasionally lead to the formation of anti-nutritional and toxic compounds. These multifaceted consequences of food processing arise from molecular interactions among nutrients with each other and with other food ingredients. Since beneficial and adverse effects of food processing are of increasing importance to food science, nutrition, and human health, and since many of the compounds formed have been shown to be potent carcinogens and growth inhibitors in animals, I organized a symposium broadly concerned with the nutritional and toxicological consequences of food processing. The symposium was sponsored by the American Institute of Nutrition (AIN) -Federation of American Societies for Experimental Biology (FASEB) for its annual meeting in Washington, D.C., April 1-5, 1990. Invited speakers were asked to develop at least one of the following topics: 1. Nutrient-nonnutrient interactions between amino acids, proteins, carbohydrates, lipids, minerals, vitamins, tannins, fiber, natural toxicants, etc. 2. Effects of radiation. 3. Thermally induced formation of dietary mutagens, antimutagens, carcinogens, anticarcinogens, antioxidants, and growth inhibitors. 4. Effects of pH on nutritional value and safety.

Food consumption is leaning toward products that provide both nutritional value and good flavor. In recent years, researchers have focused on how to scientifically analyze and evaluate foods’ nutritional and flavor qualities under different processing methods or parameters by various effect relationship analysis tools to investigate the internal relations between nutrients and flavor substances. However, during food processing, some unstable components may undergo degradation, volatilization, or secondary reactions due to changes in temperature, pressure, humidity, pH, etc., resulting in challenging research work with complex data variations in multiple dimensions.