Abstract: Antarctic krill contains high endogenous protease activities that contribute to autolysis after its death, thus limiting its processing and utilization. In order to analyze the autolysis characteristics of Antarctic krill, the relative activity of autolytic enzymes was determined as a function of temperature and pH. It was shown that the optimum temperature of the autolytic enzymes was 55 ℃, and optimum pH 7.5; under these conditions, there was an increase in the amino nitrogen content of the autolysate. Furthermore, the changes in amino acids and tryptic peptides of Antarctic krill were analyzed before and after 3 h of autolysis at the optimum temperature and pH. The results showed that glycine and proline were the dominant amino acids of Antarctic krill, followed by glutamic acid and alanine. The contents of umami amino acids such as glutamic acid, glycine and alanine decreased, while the contents of bitter amino acids such as leucine, isoleucine, tyrosine and phenylalanine increased after the autolysis. The molecular mass distribution of the autolysate was shifted to smaller molecular mass. In conclusion, this study provides a theoretical basis for further exploring the autolysis characteristics of Antarctic krill.

Key words: Antarctic krill, autolysis, amino acids, trypsin, peptide