The oxidative stability of unsaturated lipids generally decreases with increase in unsaturation. Highly unsaturated fatty acids such as docosahexaenoic acid (22 6 n-3, DHA) and icosapentaenoic acid (20 5 n-3, EPA) are thus more easily oxidized in air, with consequent decrease in food quality. Few reports on the autoxidative behavior of fatty acids in different molecular forms have appeared to date. The autoxidative behavior of fatty acids (FA), fatty acid methylesters (FAME), triacylglycerols (TG) and phospholipids (PL), all possessing essentially the same fatty acid compositions, was thus examined in this study at 30°C in the dark and the results were compared. The study was made with and then without antioxidant tocopherols (Toc).
PL was the most oxidatively stable, followed by TG>FAME>FA, with or without Toc under the autoxidation conditions used. PL hydroperoxide decomposed into carbonyl compounds more quickly than any other lipid. Autoxidative behavior of complex lipid such as PL was different from simple lipids like FA, FAME and TG.