Abstract:

Aspergillus oryzae can directly ferment swim bladder homogenate to produce protease that can hydrolyze swim bladder protein into peptides. Based on the principle, this study was designed to perpare peptides from variegated carp swim bladder. The polypeptide concentration in products was determined at intervals of 8 h during 64 h of fermentation. Apart from this, the antioxidant activities of products at different fermentation time and ultrafiltration fractions of 40 h fermentation product were tested by superoxide anion radical scavenging array, hydroxyl radical scavenging array and linoleix acid autooxidation assay. Results showed that 40 h fermentation product with (22±0.8)% degree of hydrolysis exhibited stronger antioxidant activiry than 24 h and 56h fermentation products and VE. The ultrafiltration fraction of 12 amino acid residues in average length with 1000 D molecular weight revealed the strongest antioxidant activity among all fractions. In addition, peptides obtained from variegated carp swim bladder by fermentation also had strong scavenging activity against superoxide anion and hydroxyl radical radicals and could significanty inhibit linoleic acid autooxidation

Key words: swim bladder, peptides, antioxidant activity, fermentation