Optimization of Enzymatic Hydrolysis of Swimming Crab Waste for Preparing Protein Hydrolysate

This study investigated the optimization of the preparation of protein hydrolysate from swimming crab waste (SCW) via enzymatic hydrolysis using single-factor and orthogonal array design methods. Among 6 proteases tested, alkaline protease was found optimum for SCW hydrolysis. The optimum hydrolysis conditions for achieving a maximum degree of hydrolysis were determined as follows: reaction temperature 55 ℃, pH 8.5 and enzyme dosage 1000 U/g for a hydrolysis duration of 3.0 h. Under these conditions, the maximum degree of hydrolysis was up to 26.68%. Hydrolysis temperature had the most important effect on the degree of hydrolysis of SCW, followed by enzyme dosage. The hydrolysis product of SCW was smaller than 10 kD in molecular weight. The total amino acid content in the hydrolysate was 1046.7 mg/L, and the total essential amino acid content was 382.5 mg/L, accounting for 36.54% of the total amino acids, and the total content of 4 major taste amino acids was 412.6 mg/L, accounting for 39.42% of the total amino acids. The protein hydrolysate of SCW has high nutritional value and broad application prospect.