Degradation of Ovalbumin by L-Ascorbic Acid in the Presence of Cupric Ion

Abstract

Ovalbumin, L-ascorbic acid and cupric sulfate were allowed to react at pH 3.0, 6.0, 6.8 and 7.5. Non-proteinous nitrogen compounds were formed from ovalbumin coupled with autoxidation of ascorbic acid, and a pronounced increase in their formation was observed in the reactions of neutral pH ranges. Non-proteinous nitrogen compounds contained peptides, free amino acids and ammonia. In the reactions of ovalbumin with triose reductone similar results to those with ascorbic acid were obtained. In the ovalbumin degraded with ascorbic acid at pH 6.8 was found an increase of N-terminal amino acid, which could react with carbonyl compounds resulting in browning.