Ascorbic Acid Oxidation a Key Factor in theInhibition or Promotion of the Tallowy Flavor in Milk

Summary 1. Ascorbic acid oxidation in the milk during storage at low temperature is an essential link in a chain of the reactions resulting in the development of the tallowy flavor. 2. The reaction which produces the tallowy flavor could be inhibited by quick and complete photochemical or chemical oxidation of ascorbic acid in the milk to dehydroascorbic acid prior to its pasteurization and storage. Partial oxidation of ascorbic acid stimulates the development of the tallowy flavor. 3. The promotion of the tallowy flavor by added copper (0.1 p.p.m.) in the presence of dehydroascorbic acid only, is much less effective as compared with that in milk containing ascorbic acid. 4. The tallowy flavor is not promoted by added copper (0.1 p.p.m.) in the milk completely depleted of its total vitamin C content by quick oxidation of ascorbic acid to dehydroascorbic acid and the subsequent heat treatent that takes place in pasteurization. 5. The reaction which produces the tallowy flavor could be induced again by the addition of ascorbic acid to milk which was first depleted of its ascorbic acid or of the total vitamin C content.