Research on squid protein hydrolyzed by compound proteases and hydrolysate

Squid protein was hydrolyzed by compound proteases (Alcalase and Flavourzyme) and hydrolysate was also studied. The optimum hydrolysis conditions of Alcalase were obtained by orthogonal experiment design. The effect of factors on the degree of hydrolysis such as antiseptics and Flavourzyme were investigated. The molecular weight and amino acid composition of hydrolysate was determined by Sephadex G-75 size-exclusion chromatography and automatic amino acid analyzer, respectively. The results show that nisin has no negative effects on the degree of hydrolysis and Flavourzyme can increase the degree of hydrolysis, effectively. The degree of hydrolysis is up to 20.11% under optimum conditions. The average molecular weight of hydrolysate is 1180 u, which indicates that hydrolysate comprises 9.2 amino acids, averagely. The content of essential amino acids and palatable taste amino acids(such as aspartate and glutamic acid) is 38.4% and 26.3% of the total amino acids, respectively.