Prevention of oxidized flavor development in raw and dried whole milk by amino acids.

Abstract

Present paper deals with a preventive action of free amino acids for the development of oxidized flavor in raw and dried whole milk. Ion-exchange column chromatographic analyses revealed a difference in the contents of free amino acids between dried whole milk of normal and very oxidized flavor: the latter specimen was lower in content of total free amino acids, especially of serine, glutamic acid, proline, glycine, valine and tryptophan. Among amino acids and their derivatives added to raw and dried milk, tryptophan, tryptamine and histidine were effective for either milk preparation in preventing the development of oxidized flavor, which was judged by organoleptic and TBA methods. A maximum antioxidative effect was attained by 2×10-3M for tryptophan and histidine when added to raw milk, and 10-4M for tryptophan and 2×10-4M for histidine when added to raw milk and then made into dried milk.