Ascorbic Acid Oxidation in Milk by Preformed Hydrogen Peroxide

Abstract

A study was made to ascertain if the heat inactivation of peroxidase in milk would result in non-reactivity of ascorbic acid and H2O2, and if the reaction could be induced again by the addition of horseradish peroxidase or copper to non-reactive milk. The data show that the H2O2 was not utilized for the oxidation of ascorbic acid, neither in the milk pasteurized at 76.6[degree] C nor in milk to which H2O2 was added in excess of the amt. needed to complete ascorbic acid oxidation prior to its pasteurization at 61.1[degree]C, and that the reaction was induced again by the addition of horseradish peroxidase. Only a part of ascorbic acid was oxidized rapidly by H2O2 with Cu as a catalyst in non-reactive milk. These results indicate that the peroxidase in milk may play an important part in the reaction involving ascorbic acid oxidation in the presence of added H2O2.