[Progress report. Lipid peroxidation. 2. Secondary reactions]

Lipids and lipid containing foods are altered by autoxidative processes resulting in the formation of hydroperoxides which are considered as the actual primary autoxidation products. These hydroperoxides cause a variety of secondary reactions giving di- and trihydroperoxides, hydroperoxyepidioxides, endoperoxides and hydroperoxyepoxides, so called secondary autoxidation products at a primary level. Sometimes they are only minor substances. The formation of primary autoxidation products is accelerated by reaction conditions as increased temperature, oxygen, metal ions and sensibilizers but is inhibited by natural and synthetic antioxidants. The decomposition of hydroperoxides and secondary autoxidation products at the primary level results in volatile substances decreasing the flavour quality of lipid containing foods. Simultaneously there are other cleavage and decomposition products remaining in the lipid causing a reduction of its oxidative stability.