Preparation of Antioxidant Peptides Derived from Nacre of Nanzhu Shell and Their Inhibitory Activity against Tyrosinase

Abstract

The aim of this study was to prepare antioxidant peptides derived from nacre of Nanzhu shell, evaluate their antioxidant and tyrosinase inhibitory activities, and analyze their amino acid components. Using the protein from nacre of Nanzhu shell as raw material, DPPH free radical clearance rate as evaluation index, the optimal enzymatic hydrolysis process was obtained by sieve enzyme, single factor and response surface experiments. The amino acid composition, antioxidant and tyrosinase inhibitory activities of the enzymatic hydrolysis products were analyzed in vitro. The optimal enzymatic hydrolysis of the nacre of Nanzhu shell source antioxidant peptide was as follows: Using trypsin as hydrolase, hydrolysis temperature 37 ℃, pH7.0, enzymolysis time 3 h, enzymolysis ratio 0.32%, the DPPH free radical scavenging rate of the enzymolysis product was 76.34%±0.24%. The nacre antioxidant peptide prepared under these conditions had excellent ABTS+ free radical scavenging rate (IC50=0.1735 mg/mL), DPPH free radical scavenging rate (IC50=2.342 mg/mL) and oxygen free radical scavenging ability (ORAC value=1124.86 μmol TE/g lyophilized powder). In addition, nacre antioxidant peptides could also inhibit tyrosinase activity by mixed reversible inhibition, and had good tyrosinase inhibitory activity, the inhibitory rate of IC50 value was 12.38 mg/mL. The results of this study indicate that nacre antioxidant peptides have a good application prospect in the field of food and cosmetics, and provide a theoretical basis for the high-value utilization of shell nacre.

Keywords

• nacre
• peptides
• antioxidant activity
• tyrosinase inhibitory activity
• response surface analysis
• amino acid composition