Antioxidant Activities of Optimized Enzymatic Protein Hydrolysates from Hybrid Sturgeon (Huso dauricus × Acipenser schrenckii) Prepared Using Two Proteases

The objective of this work was to optimize the hydrolysis conditions of hybrid sturgeon (Huso dauricus × Acipenser schrenckii) protein using flavourzyme and compound proteinase, and to evaluate the antioxidant activity of hydrolysates. The lyophilized flavourzyme hydrolysate (FH) and compound proteinase hydrolysate (CPH) with degree of hydrolysis of 18.16% and 19.35% under optimal conditions had 85.36% and 87.24% protein content, 89.19 and 96.97 g/100 g protein total amino acid content, 92.86% and 95.12% protein solubility, and 902.47 nm and 1025.76 nm particle size, respectively. The CPH had the highest DPPH and ABTS radical scavenging activities, which were 71.04 and 66.84% with IC50 at 2.85 and 3.37 mg/mL, respectively; while the FH had higher metal-chelating activity, which was 58.37% with IC50 at 24.81 mg/mL. The obtained hydrolysates have excellent antioxidant properties and could be used as food additives and natural substitutes for synthetic antioxidants compounds, particularly in food and pharmaceuticals.