Food chemistry is a division of food science that evaluates how foods are processed, prepared and distributed. This science is closely related to biochemistry in that, its principles are based on knowledge of the main components of life such as water, carbohydrates, lipids (fats), proteins, minerals and vitamins. Food chemistry is the study of chemical processes and interactions of all biological and non-biological components of foods. The biological substances include items such as meat, poultry, milk, vegetables, and fruits etc. Food is made up of non-biological chemicals that include primarily water, proteins, lipids, carbohydrates, vitamins and minerals. It is similar to biochemistry in its main components such as carbohydrates, lipids, protein, water, vitamins, minerals, enzymes, but it also includes areas such as food additives, flavors, and colors. This discipline also encompasses how food materials change under certain food processing techniques and describes the ways either to enhance or to prevent these changes. An example of enhancing a process would be to encourage fermentation of dairy products with microorganisms that convert lactose to lactic acid. An example of preventing a process would be stopping the browning reaction on the surface of freshly cut red delicious apples using lemon juice or other acidulated water.
Food chemistry focuses on the chemistry of foods, their deterioration and the principles underlying the improvement of foods for consumers. It applies chemistry to developing, processing, packaging, preserving, storing and distributing foods and beverages to obtain safe, economical and aesthetically pleasing food supplies.
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A major component of food is water, which can encompass anywhere from10% in grains to 50% in meat products to around 70-80% in fruit and vegetable products. It is also an excellent place for bacterial growth and food spoilage, if it is not properly processed. It influences textural properties and the extent to which the food may be subjected to microbial spoilage. One way by which this is measured in food is by water activity which is very important in the shelf life of many foods during processing. One important aspect of food preservation is to reduce the amount of water or alter the water's characteristics to enhance shelf life. Such methods include dehydration, freezing, refrigeration etc.
Removing water through concentration, drying or freezing reduces the free water and prevents microbial growth. Water activity is a measure of free (unbound) water available for chemical and biological activity. Generally bacteria require a water activity of > 0.9 to grow and most yeasts and molds are inhibited by a water activity of
The carbohydrates in foods are mixtures of carbon, hydrogen and oxygen and can be classified as simple and complex carbohydrates. Carbohydrate, as it relates to food chemistry, is a general term used for a group of chemical compounds present in both plants and animals that are essentially carbon and water molecular combinations. Simple carbohydrates are sugars and complex carbohydrates are starches and fibers.
Proteins are polymers of amino acids linked together through a peptide bond. They are mainly composed of carbon, nitrogen, hydrogen, oxygen, and some sulfur, and sometimes may also contain iron, copper, phosphorus, zinc etc. They play a fundamental role in the structure and function of cells.The function of a protein is determined by the sequence of its amino acids. Proteins are essential to the nutritional well being of the human. There are twenty amino acids that are found in proteins out of which 10 are called as essential amino acids because the body cannot produce these amino acids and they have to be provided through the diet. Food chemistry explains how proteins can change their structure through many methods of food processing. Proteins in foods add texture to foods, contribute to odor and taste, form gels, stabilize foams and emulsions etc. The food sources of proteins are grains and animal foods. However, the quality of protein is superior from animal foods compared to plant foods because of amino acid composition.
Water plays many critical roles within the field of food science. Solutes such as salts and sugars found in water affect the physical properties of water. The boiling and freezing points of water are affected by solutes. For example one mole of sucrose per kilogram of water raises the boiling point of water by 0.52 oC, and one mole of salt per kilogram of water raises the boiling point by 1.04 oC. Similarly, increasing the number of dissolved particles lowers water's freezing point. Solutes in water also affect water activity which affects many chemical reactions and the growth of microbes in food. Water activity can be described as a ratio of the vapor pressure of water in a solution to the vapor pressure of pure water. Solutes in water lower water activity. This is important to know because most bacterial growth ceases at low levels of water activity. Microbial growth not only affects the safety of food but also the preservation and shelf life of food.
The concept of free water as opposed to the total water, including bound water, has gained wide acceptance in the food processing industry. Water activity has been reported to exert a decisive influence on such phenomena as change in color, taste and aroma, food poisoning and spoilage (shelf life), loss of vitamins etc. Total moisture content of the food generally has very little influence on these parameters. Water activity in foods can be controlled by using various additives (e.g., salts, sugars etc.,), by using satisfactory packaging materials and by maintaining favorable storage conditions. Water activity measurements are increasingly being used in food research as well as in food quality control laboratories.
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This book presents fundamental and practical information on food chemistry. Using 2-D barcodes, it illustrates the specific reactions and potential transformation mechanisms of food constituents during various manufacturing and storage processes, and each chapter features teaching activities, such as questions and answers, and discussions. Further, it describes various local practices and improvements in Asia. Divided into 12 chapters covering individual nutrients and components, including water, proteins, carbohydrates, lipids, vitamins, minerals, enzymes, pigments, flavoring substances, additives, and harmful constituents, it addresses their food chemistry, as well as their transformations during manufacturing processes, and typical or advanced treatments to improve food quality and safety.
This book helps college students to gain a basic understanding of nutrients and food components, to discover and implement the practical industrial guidelines, and also to learn the latest developments in food chemistry.
Jianquan KAN obtained his doctorate from Southwest University in Chongqing in 2003, and from 2004 to 2005, he worked as a Visiting Scholar at the University of Missouri-Columbia. Since 2000, he has been a professor in the College of Food Science, Southwest University. During this time, he has led or participated in more than 100 national and international research projects, published over 200 scientific papers and 8 book chapters (5 as chief editor), and had 4 patents approved. Currently, he works as the Academic Leader at the College of Food Science. His major research interests and areas of expertise are associated with food chemistry, nutrition, food quality and food safety. Jianquan KAN has been the chief editor for the three Chinese editions of the Textbook of Food Chemistry, which has sold more than 1.2 million volumes and is widely used in universities throughout China.
Kewei CHEN obtained his doctorate from Universidad de Sevilla, Spain in 2016, and from 2012 to 2016, he also did his research work in Instituto de la Grasa (CSIC, Spain). Since 2017, he has been an associate professor in the College of Food Science, Southwest University. He has participated in several international book chapters about food industry and technology. His major research interests and areas are related with food chemistry & nutrition, micronutrient bioavailability, and food safety, with many research papers on Food Chemistry, Journal of Functional Foods, etc.
Providing a thorough introduction to the core areas of food science specified by the Institute of Food Technologists, Introduction to Food Chemistry focuses on principles rather than commodities and balances facts with explanations. The text covers the major areas of food science, including food chemistry, food analysis and methods for quality assu 2ff7e9595c
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