ABSTRACT
Oxidative stability is an important indicator of oil quality and shelf-life because oxidation produces low-molecular-weight off-flavor compounds in the oils. This chapter reviews the reaction mechanisms and kinetics, factors, and oxidation products of autoxidation and photosensitized oxidation, and antioxidants naturally present in edible oils. Autoxidation of oils, a free radical chain reaction, includes the initiation, propagation, and termination steps. Different chemical mechanisms are responsible for the oxidation of edible oils during processing and storage, depending upon the types of oxygen. Two types of oxygen react with edible oils. One is called atmospheric triplet oxygen and the other is singlet oxygen. The oil-processing method affects the oxidative stability of the oil. Photosensitized oxidation of edible oils occurs in the presence of light, sensitizers, and atmospheric oxygen, in which singlet oxygen is produced. The primary oxidation products, lipid hydroperoxides, are relatively stable at room temperature and in the absence of metals.
