The kinetics of the oxidation of several antioxidants in oxidizing fats

Abstract

Summary The deterioration of hydroquinone, catechol, NDGA (nordihydroguaiaretic acid), and gallic acid in lard oxidizing at 100° C. has been quantitatively studied. Initial concentrations of 0.02, 0.1, and 0.5% were used. The results indicate that, in general, the deterioration of phenolic antioxidants in oxidizing fats does not occur as a single low order reaction but is complicated by products formed in the oxidation of the fat and possibly also of the antioxidant. The deterioration curves for gallic acid are quite different from those of the other three antioxidants. This is tentatively explained on the basis of the synergistic action of gallic acid upon itself. There is an increasing catalytic effect with increasing initial concentrations of all of these antioxidants on the formation of peroxides during the early stages of the autoxidation of lard.