Prooxidant effect of dihydroxyacetone and reducing sugars on the autoxidation of methyl linoleate in emulsions.

Abstract

Reducing sugars accelerated the autoxidation of methyl linoleate in an aqueous emulsion system. The autoxidation induced by dihydroxyacetone, the model compound for reducing sugar, was completely inhibited by the addition of EDTA, and trace amounts of transition metals were observed in the oxidation system. Although iron salts hardly accelerated the autoxidation of methyl linoleate, the combined effect of iron salts and dihydroxyacetone markedly accelerated the oxidation process. The decomposition of methyl linoleate monohydroperoxide was also accelerated by the combined effect of iron salts and dihydroxyacetone. Reducing sugars could reduce the ferric ion to the ferrous ion. These results indicate that reducing sugars reduce transition metal ions in the oxidation system and that the resulting reduced metal ions can accelerate the lipid peroxidation process. The autoxidized products of methyl linoleate and the decomposed products of methyl linoleate monohydroperoxide were analyzed after chemical reduction...