Optimization of Hydrolysis Conditions for Production of Gelatin Hydrolysates from Shark Skin Byproduct and Evaluation of Their Antioxidant Activities

The effect of Alcalase hydrolysis conditions on antioxidant activities of shark skin gelatin hydrolysate (SSGH) byproduct was studied. Optimal hydrolysis condition for SSGH at 60 degrees C, pH 7.5, and 2.70 AU kg(-1)gelatin protein was used for varied hydrolysis times (10-90 min). The IC(50)against DPPH radicals of SSGH hydrolyzed for 90 min (SSGH-90) was 27.39 mg ml(-1), which is greater than ascorbic acid. SSGH-90 was predominantly composed of 15-20 kDa protein fragments that regulated increases in peroxide value and thiobarbituric acid reactive substances values and suppressed decrease in DHA of a fish oil-in-water emulsion during storage at 30 degrees C for 7 days.