Abstract:In this study, trypsin was used for the enzymatic hydrolysis of proteins from Pacific saury. Based on the protein utilization ratio and oxidative free radical absorbance capacity (ORAC), the enzymatic hydrolysis technology was optimized for the preparation of antioxidant peptides from Pacific saury proteins by using a resonance surface analysis. The characteristics of the enzymatic hydrolysates were also examined. The optimal enzymatic hydrolysis conditions were as follows: enzyme dosage, 1,085 U/g; liquid-to-solid ratio, 3:1; and hydrolysis duration, 8 h. Under these conditions, the protein utilization ratio was 76.86%, and ORAC value was 883.40 μmol Trolox equivalent/g. The total amino acid content was 4,576.69 mg/100 mL in the enzymatic hydrolysates from Pacific saury, of which 34.28% were free amino acids and 65.31% were peptides. Among the total amino acids, essential amino acids accounted for 34.76% and antioxidant amino acids and branched-chain amino acids accounted for 26.25%. These results indicated that Pacific saury has high nutritional value. Hydrolysates with molecular weights of 1000~3000 Da were the most abundant and accounted for 44.18% of the enzymatic hydrolysates of Pacific saury. Moreover, the enzymatic hydrolysates showed DPPH radical scavenging activity (IC50 value, 3.32 mg/mL), O2- radical scavenging activity (IC50 value, 5.08 mg/mL), and light absorption power (0.67 at 10.0 mg/mL). Thus, enzymatic hydrolysates of Pacific saury have relatively high antioxidant activities.
