Some analytical observations of autoxidation products of linoleic acid and their thiobarbituric acid reactive substances.

Autoxidation products of linoleic acid (LA) were analyzed, when the weight became 1. 14-fold under the autoxidation conditions of satisfactory atmospheric oxygen, at 37°C, in the dark, for 7 days.The LA absorbed 2.8mol of oxygen to form secondary degradation products.This autoxidized LAconsisted of 45%intact substance, 22%a mixture of polymers and endoperoxides, 18% LA hydroperoxides, 3% polar products, 1.7% azelaldehydeic acid, 1.3% hexarial, 0.9% azelaic acid, 0.6% octanoic acid, 0.3% suberaldehydeic acid, and so on.Thus, unstable 2,4-dienoic carbonyls were the main intermediate products of autoxidation of LA.Therefore, malonaldehyde was not a main product nor a major thiobarbituric acid reactive substance.Linoleic acid (LA) reacts easily with atmospheric oxygen to form linoleic acid hydroperoxide (LAHPO).The LAHPO is broken down in the presence of oxygen1} and subsequently gives a mixture of various kinds of further oxidized products.The mixture is generally termed secondary degradation