The oxidative degradation of carotenoids involves isomerization and oxidation. Initially, a part of the all-E-carotenoids, the usual configuration in
nature, is isomerized to the Z-forms. Carotenoids in both forms are then oxidized, commencing with epoxidation, hydroxylation and cleavage to
apocarotenals. Subsequent fragmentations result in a series of compounds of low molecular masses. Direct cleavage of the polyene chain to low
mass compounds also appears to occur. Reproduced from Rodriguez-Amaya