Systematic Investigation of Antioxidant Activity of Egg White Protein Hydrolysates Obtained by Pepsin

Shuguo Sun,Tao Yang,Meihu Ma,Qinlu Lin,Huihui Niu

doi:10.19026/ajfst.5.3312

Abstract

Antioxidative activity of protein hydrolysates from egg white hydrolyzed by Pepsin with different Degrees of Hydrolysis (DHs) was investigated. As the DH increased from 6.47 to 18.22%, the antioxidative activity of Egg White Protein Hydrolysates (EWPHs) first increased and then decreased, except for the reducing power of EWPHs. The EWPHs with DH 16.93% showed higher DPPH radical scavenging activity (96.07±3.84%), hydroxyl radical scavenging activity (36.82±1.46%), superoxide anion scavenging activity (67.72±2.51%) and inhibitory activity of tea oil autoxidation (62.68±2.32%) compared to other EWPHs. At DH 18.22%, the EWPHs exhibited the strongest reducing power (0.34±0.014). The results revealed that antioxidative activity of protein hydrolysates from egg white was determined by the DH. According to the experimental results, the EWPHs have potential for use as a natural antioxidant for food preservation.

Highlights

It is well known that functional properties of protein can be improved by enzymatic hydrolysis under suitable conditions
The antioxidant activity of protein hydrolysates depends on the protein substrate used, proteolysis conditions, the specificity of the enzyme used for the proteolysis and the Degrees of Hydrolysis (DHs)
Protein hydrolysates with different DHs were obtained by treating egg white with pepsin

Summary

Introduction

It is well known that functional properties of protein can be improved by enzymatic hydrolysis under suitable conditions. Hydrolysis potentially affects the molecular size and hydrophobicity, as well as polar and ionisable groups of protein hydrolysates. Some protein hydrolysates have been reported to exhibit antioxidant activity (Sakanaka and Tachibana, 2006; Klompong et al, 2007; Sun et al, 2010). In the past several years, many researchers reported that both the type of protease and the degree of hydrolysis can affect the antioxidative activity of protein hydrolysate (Saiga et al, 2003; Hou and Zhao, 2011). You et al (2009) found that as DH increased from 18 to 33%, the hydroxyl radical scavenging activity of loach protein hydrolysates increased first and decreased. Different types of protease and different DHs contribute to the molecular weight and amino acid sequence of peptides, which may affect antioxidant activities of protein hydrolysates

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Conclusion