A response surface approach on optimization of hydrolysis parameters for the production of egg white protein hydrolysates with antioxidant activities

Bioactive peptides can be defined as specific protein fractions with amino acid sequence that promotes a positive impact on several biologic activities. The hydrolysis of egg white protein might result in releasing or enhancing their biological activity. The aim of this study was to evaluate the effects of the enzymatic hydrolysis of egg white proteins on their antioxidant properties. The hydrolysates were prepared with protease from Aspergillus oryzae LBA 01 (AO) produced under solid-state fermentation and two commercial proteases: protease from A. oryzae (CAO), and Bacillus licheniformis (CBL). The enzymatic hydrolysis with microbial proteases increased the antioxidant properties of egg white proteins. The egg white protein hydrolysates prepared with commercial protease CAO, presented higher antioxidant activity than the hydrolysates obtained with the other proteases. According CCRD analysis, the hydrolysates prepared with 3.0% of egg white proteins and 20.0 U of protease per mL of reaction mixture, presented high radical-scavenging effect, with an ORAC value of 1193.12±84.62 and DPPH value of 19.05±0.81 Trolox EQ µmol g−1. In ORAC assay, the maximum antioxidant activities were observed in the hydrolysates presenting DH 50.0% obtained after 120 min of hydrolysis. In contrast, for DPPH assay the highest values of antioxidant activity were detected in the hydrolysates obtained in the first 30 min, where the degree of hydrolysis was greater than 60.0%.