Optimization of the Preparation Process of Antioxidant Peptide from Preserved Egg White and Its in Vitro Antioxidant Activity

The mature preserved egg white pickled by the clearing method was utilized as the raw material. The solid to liquid ratio, hydrolysis time, and the addition of enzyme were set as the inspection factors, and the degree of hydrolysis and the DPPH free radical scavenging rate were set as response values. The optimal process parameters for the preparation of antioxidant peptides from preserved egg whites were derived using response surface testing optimization design as follows: Solid to liquid ratio was 1:10.4 g/mL, hydrolysis time was 4.1 h and the addition of enzyme was 0.57%. The degree of hydrolysis was 11.23% and scavenging capacity of DPPH free radical was 89.76% at this time. The hydrolysate under the optimal process possessed certain antioxidant capacity. And the reducing power, superoxide anion radical (O₂⁻·) scavenging rate and hydroxyl radical (·OH) scavenging rate were 0.599, 66.78% and 79.63%, respectively, when the enzyme digest concentration was 10.4 mg/mL.