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Ebook Encyclopedia of physical science and technology - Biochemistry (3rd edition): Part 2

(BQ) Part 2 book "Encyclopedia of physical science and technology - Biochemistry" has contents: Natural antioxidants in foods, nucleic acid synthesis, protein folding, protein structure, protein synthesis, vitamins and coenzymes. | P1: GTQ/GUB P2: GSS/GJP QC: FYD Final Pages Encyclopedia of Physical Science and Technology Qu: 00, 00, 00, 00 EN010B-472 July 16, 2001 15:41 Natural Antioxidants In Foods Eric A. Decker University of Massachusetts I. Free Radical Scavengers II. Metal Chelators III. Antioxidant Enzymes GLOSSARY Antioxidant A compounds that can inhibit oxidative processes. Free radical A compound with an unpaired electron that can promote oxidative reaction. Free radical scavenger A compound that can absorb a free radical to decrease the radical energy thus making it less likely to cause oxidation. Metal chelators Compounds that can bind metals and decrease their reactivity. Phenolic A group of chemical compounds primarily found in plants that act as antioxidant and are beneficial to health. ATMOSPHERIC (TRIPLET) oxygen is a low energy biradical (i.e., contains two unpaired electrons). However, during metabolism of oxygen as well nitrogen, alterations can occur to produce highly reactive oxygen and nitrogen species that will react with and cause damage to biomolecules. In foods, this can cause oxidation of lipids, pigments, vitamins, and proteins, leading to offflavor formation, discoloration, and loss of important nutrients. Foods, which are derived from a variety of different biological tissues, contain a host of different antioxidant defense systems to prevent the damaging effect of reactive oxygen and nitrogen species. However, during the processing of biological tissues into foods, the formation of oxidizing species can increase and antioxidant systems can be overwhelmed leading to uncontrolled oxidative reactions resulting in loss of quality, decrease in shelflife, and formation of potentially toxic oxidation products. To protect food quality and safety, antioxidants are often added to processed foods. These antioxidants can be synthetically derived compounds, such as butylated hydroxytoluene and ethylene diaminetetraacetic acid. Concern over the use of synthetic .