Chemical Changes During Food Processing

Chemical Changes During Processing and Storage of Foods: Implications for Food Quality and Human Health presents a comprehensive and updated discussion of the major chemical changes occurring in foods during processing and storage, the mechanisms and influencing factors involved, and their effects on food quality, shelf-life, food safety, and health. Food components undergo chemical reactions and interactions that produce both positive and negative consequences. This book brings together classical and recent knowledge to deliver a deeper understanding of this topic so that desirable alterations can be enhanced and undesirable changes avoided or reduced. Chemical Changes During Processing and Storage of Foods provides researchers in the fields of food science, nutrition, public health, medical sciences, food security, biochemistry, pharmacy, chemistry, chemical engineering, and agronomy with a strong knowledge to support their endeavors to improve the food we consume. It will also benefit undergraduate and graduate students working on a variety of disciplines in food chemistry Offers a comprehensive overview of the major chemical changes that occur in foods at the molecular level and discusses the positive and negative effects on food quality and human health Describes the mechanisms of these chemical changes and the factors that impede or accelerate their occurrence Helps to solve daily industry problems such as loss of color and nutritional quality, alteration of texture, flavor deterioration or development of off-flavor, loss of nutrients and bioactive compounds or lowering of their bioefficacy, and possible formation of toxic compounds

This volume results from the Eighth Basic Symposium held by the Institute of Food Technologists in Anaheim, California on June 8-9, 1984. The theme of the symposium was "Chemical Changes in Food during Processing." The speakers included a mix of individuals from academic institu tions, governmental agencies, and the food industry. Twenty speakers discussed topics ranging from the basic chemistry relating to food constituents to the more applied aspects of chemical changes in food components during food processing. It was the intent of the organizers to bring together a group of speakers who could address the chemistry of changes in food compo nents during processing from a mechanistic point of view. As a con sequence, the proceedings of this symposium emphasize the basic chemistry of changes in food constituents from a generic perspective which is intended to provide the reader with a background to address more specific problems that may arise.

Distributed in Hungary, Albania, Bulgaria, China, Cuba, Czechoslovakia, GDR, Dem People's Rep of Korea, Mongolia, Poland, Roumania, Soviet Union, Dem Rep of Vietnam and Yugoslavia by Avicenum, Czechoslovak Medical Press, Praha The book deals with the chemical reactions taking place in food during industrial processing and storage, and shows how various food components react according to their chemical composition and the influence of other components or processing conditions. The work describes in detail the changes of the main food components (proteins, saccharides, lipids) and of other components important from the standpoint of the nutritional, sensory and hygienic properties of food materials. Important changes of physical properties (which may affect the chemical reactivity) are given as well. The most important reactions are elucidated on examples from technological processes which also show the effect of these chemical reactions on the most important properties of food products.

Food proteins are of great interest, not only because of their nutritional importance and their functionality in foods, but also for their detrimental effects. Although proteins from milk, meats (including fish and poultry), eggs, cereals, legumes, and oilseeds have been the traditional sources of protein in the human diet, potentially any proteins from a biological source could serve as a food protein. The primary role of protein in the diet is to provide the building materials for the synthesis of muscle and other tissues, and they play a critical role in many biological processes. They are also responsible for food texture, color, and flavor. Today, food proteins are extracted, modified, and incorporated into processed foods to impart specific functional properties. They can also have adverse effects in the diet: proteins, such as walnuts, pecans, almonds, and cashews, soybean, wheat, milk, egg, crustacean, and fish proteins can be powerful allergens for some people. Applied Food Protein Chemistry is an applied reference which reviews the properties of food proteins and provides in-depth information on important plant and animal proteins consumed around the world. The book is grouped into three sections: (1) overview of food proteins, (2) plant proteins, and (3) animal proteins. Each chapter discusses world production, distribution, utilization, physicochemical properties, and the functional properties of each protein, as well as its food applications. The authors for each of the chapters are carefully selected experts in the field. This book will be a valuable reference tool for those who work on food proteins. It will also be an important text on applied food protein chemistry for upper-level students and graduate students of food science programs.

Chemical changes that occur in foods during processing and storage are manifold and might be both desirable and undesirable in nature. While many of the processes are carried out intentionally, there are also certain unwanted changes that naturally occur in food and might have to be controlled. Therefore, efforts are made to devise processing technologies in which desirable attributes of foods are retained and their deleterious ef fects are minimized. While proteins, lipids and carbohydrates are the main nutrients of food that are affected by processing, it is their interaction with one another, as well as in volvement oflow-molecular-weight constituents that affects their flavor, color and overall acceptability. Thus, generation of aroma via thermal processing and bioconversion is of utmost importance in food preparation. Furthermore, processing operations must be opti mized in order to eliminate or reduce the content of antinutrients that are present in foods and retain their bioactive components. Therefore, while novel processing technologies such as freezing, irradiation, microwaving, high pressure treatment and fermentation might be employed, control process conditions in a manner that both the desirable sensory attributes and wholesomeness of foods are safeguarded is essential. Obviously, method ologies should also be established to quantitate the changes that occur in foods as a result of processing. This volume was developed from contributions provided by a group of internation ally-recognized lead scientists.

The contents of this book are the proceedings of the ACS symposium, "Impact of Processing on Food Safety," which was held April 16-17, 1997, at the American Chemical Society National Meeting in San Francisco, CA. This symposium brought together re searchers from diverse backgrounds in academia, government, and industry. Twenty speakers discussed topics ranging from the regulatory aspects of food processing to the microbiological and chemical changes in food during processing. The main goal of food processing is to improve the microbial safety of food by de stroying pathogenic and spoilage organisms. Food processing can also improve food safety by destroying or eliminating naturally occurring toxins, chemical contaminants, and antinutritive factors. Unfortunately, processing can also cause chemical changes that result in the formation of toxic or antinutritive factors. The purpose of this book is to summarize our knowledge of both the beneficial and deleterious effects of processing. Chapter I con siders the consumer's perceptions about food contaminants and food processing. Chapter 2 summarizes the effects of traditional and nontraditional processing methods on microor ganisms in food. Chapters 3-6 review the effects of processing on lipids (fatty acids and cholesterol) in food. Changes in the nutritive value of vitamins and minerals as a result of processing are discussed in chapter 7. Chapter 8 concentrates on how processing reduces the allergenicity of some foods.

Food processing is now the biggest industry in the UK and in many other countries. It is also rapidly changing from what was essentially a craft industry, batch processing relatively small amounts of product, to a very highly automated one with continuously operating high speed production lines. In addition, consumers have developed a greater expectation for consistently high standard products and coupled this with demands for such things as a more natural flavour, lower fat etc. The need for an increased knowledge of the scientific principles behind food processing has never been greater. Within the industry itself, increased automation, company diversification and amalgamations etc. have meant that those working in it have often to change their field of operation. Whereas twenty years ago, someone starting work in one branch of the food industry could expect, if he or she so desired, to work there all their working lives, this is now seldom the case. This means that a basic knowledge of the principles behind food processing is necessary both for the student at university or college, and for those already in the industry. It is hoped, therefore, that this book will appeal to both, and prove to be a useful reference over a wide range of food processing.

Biochemistry of Foods attempts to emphasize the importance of biochemistry in the rapidly developing field of food science, and to provide a deeper understanding of those chemical changes occurring in foods. The development of acceptable fruits and vegetables on postharvest storage is dependent on critical biochemical transformations taking place within the plant organ. The chapters discuss how meat and fish similarly undergo postmortem chemical changes which affect their consumer acceptability. In addition to natural changes, those induced by processing or mechanical injury affect the quality of foods. Such changes can be controlled through an understanding of the chemical reactions involved, for instance, in enzymic and nonenzymic browning. Increased sophistication in food production has resulted in the widespread use of enzymes in food-processing operations. Some of the more important enzymes are discussed, with an emphasis on their role in the food industry. The final chapter is concerned with the biodeterioration of foods. The various microorganisms involved in the degradation of proteins, carbohydrates, oils, and fats are discussed, with special reference to the individual biochemical reactions responsible for food deterioration.