Influence of enzymatic hydrolysis conditions on biochemical and antioxidant properties of pacific thread herring <i>(Ophistonema libertate)</i> hydrolysates

Abstract

Pacific thread herring (Ophistonema libertate) muscle was hydrolyzed with Alcalase for the preparation of protein hydrolysates. The effect of enzyme concentration (EC; 1% and 3%), pH (8 and 9) and temperature (40°C and 50°C) on some biochemical properties and antioxidant activity (AOXA) was determined. The degree of hydrolysis (DH) ranged between 9.6% and 33.1%. The highest DH was obtained with the following conditons: EC of 3%, pH 9 and temperature of 50°C; however, the highest AOXA measured by DPPH (183.7 µmol TE/mg), FRAP (0.98 µmol TE/mg), and ABTS (144.9 µmol TE/mg) was obtained at EC of 3%, pH 8 and temperature of 50°C. These also exhibited a higher percentage of peptides of MW lower than 1.35 kDa and high concentrations of anionic and cationic amino acids. These results suggest that protein hydrolysates from Pacific thread herring muscle have a potential for application in the formulation of functional food.