Antioxidative activity of volatile heterocyclic compounds

Several volatile heterocyclic compounds formed in Maillard reactions were evaluated for antioxidative activity. Antioxidative activity was measured by the oxidation of heptanal to heptanoic acid or by malonaldehyde formation. Alkylthiophenes, 2-thiophenethiol, 2-methyl-3-furanthiol, and furfuryl mercaptan inhibited heptanal oxidation for up to 30 days. The degree of unsaturation in the heterocyclic ring, as well as the substituent type, had variable effects on the antioxidative capacity of these compounds. The tert-butyl hydroperoxide induced oxidation of tocopherol-stripped corn oil, as measured by malondialdehyde formation, was also inhibited in the presence of these heterocyclic compounds. Reactions of the above compounds with tert-butyl hydroperoxide and m-chloroperoxybenzoic acid resulted in the formation and identification of various oxidized products. The products of these reactions suggested that these heterocyclic Maillard reaction products had antioxidative activity.