Abstract: One-factor-at-a-time combined with orthogonal array design method was used to investigate the effects of the main process parameters for the hydrolysis of porcine skin by alcalase on degree of hydrolysis and superoxide anion radical scavenging activity of porcine skin hydrolysates. The optimal hydrolysis conditions for maximizing superoxide anion radical scavenging activity of porcine skin hydrolysates were 4 h hydrolysis at pH 7.5, 55 ℃, an enzyme/substrate ratio of 6000 U/g and a substrate concentration. Under these conditions, the degree of hydrolysis of collagen proteins in porcine skin was 9.55%, and the superoxide anion radical scavenging activity of the obtained hydrolysates 60.11%. At diluted concentrations between 10 mg/mL and 50 mg/mL, the maximum DPPH radical scavenging rate of the hydrolysates was 95.06% with an IC50 of 3.89 mg/mL, and the maximum superoxide radical scavenging rate 65.89% with an IC50 of 16.43 mg/mL. Therefore, the collagen hydrolysates have excellent free radical scavenging capacities.

Key words: pig skin, alcalase, collagen hydrolysis, hydrolysis degree, antioxidant activity