Preparation of antioxidative peptides from goose hemoglobin hydrolysates and optimization of enzymatic hydrolysis conditions

Hemoglobin was extracted from the fresh goose blood, and then goose hemoglobin was hydrolyzed with three different proteases ( alcalase, neutral protease and flavourzyme) to prepare antioxidant peptides. The degree of hydrolysis was measured using formaldehyde titration method.The antioxidant activity of hydrolysates was examined by DPPH radical scavenging ability. The influences of temperature, time, pH and enzyme / substrate ratio on the antioxidant activity of hydrolysates were also investigated. The results showed that the hydrolysates obtained through hydrolysis by neutral protease had the highest DPPH radical scavenging activity. The optimal hydrolysis condition of neutral protease was as follows:temperature 50℃, time 8h, pH7.0 and enzyme /substrate ratio 8000U /g.Under the optimal conditions, DPPH radical scavenging activity of hydrolysates was 89.6%.