ABSTRACT
Lipid oxidation in food systems is a detrimental process. It deteriorates the sensory quality and nutritive value of a product, poses a health hazard, and presents a number of analytical problems (Figure 8.1). Lipid oxidation is affected by numerous internal and external factors such as fatty acid (FA) composition, content and activity of pro-and antioxidants, irradiation, temperature, oxygen pressure, surface area in contact with oxygen, and water activity (a
). Because lipids are only a part of a food product, it is difficult to find a food component that would not be capable of affecting lipid oxidation. The complex process of food lipid oxidative changes is interpreted in terms of an oxidation mechanism derived from model studies, predominantly involving a single FA. Lipid oxidation in foods is assumed to proceed along a free radical route (autoxidation), photooxidation route, and/or lipoxygenase route. The oxidation mechanism is basically explained by invoking free-radical reactions, while the photooxidation and lipoxygenase routes differ from it at the initiation stage only. For this reason, they can be treated as different forms of free radical reaction initiation.
