Study on the Functional Properties and Antioxidant Activities of Different Enzymatic Hydrolysates of Ziziphi Spinosae Semen Protein

Using Ziziphi Spinosae semen as raw material, Ziziphi Spinosae semen protein was extracted by alkali extraction and acid precipitation method. The Ziziphi Spinosae semen protein was hydrolyzed by three different proteases (alkaline protease, neutral protease and papain). The functional properties and antioxidant activity of enzymatic hydrolysates from Ziziphi Spinosae semen protein were studied. The results showed that the solubility, oil holding capacity, foaming capacity and stability, emulsifying capacity and stability of protein hydrolysates from different Ziziphi Spinosae semen were improved in different degrees compared with protein hydrolysates from Ziziphi Spinosae semen, among them, papain hydrolysate had the strongest solubility, oil holding, foaming and emulsifying properties, and alkaline protease hydrolysate had the strongest foaming and emulsifying stability. In vitro antioxidant studies showed that compared with of Ziziphi Spinosae semen protein, the antioxidant activities of enzymatic hydrolysates obtained by different proteases were significantly improved, the alkaline protease DPPH scavenging ability, hydroxyl radical scavenging ability, super oxygen anion clearance and ABTS+ radical scavenging ability were higher than those of other enzymatic hydrolysates, when the mass concentration was 2.5 mg/mL, the highest DPPH radical scavenging rate was 95.83%, the superoxide anion radical scavenging rate was 44.77%, the ABTS radical scavenging rate was 90.84%, and the hydroxyl radical scavenging rate was 44.77%. Therefore, this study shows that the enzymatic hydrolysate of Ziziphi Spinosae semen protein has good food processing performance, and its antioxidant activity is significantly increased, protein sources can be used as a potential protein resource in food, and provides a theoretical basis for the application of Ziziphi Spinosae semen protease hydrolysate in food industry.