Radical-Scavenging Activity of Fish Gelatin Hydrolysates from Bone of Pangasius catfish (Pangasius sutchi) by Microbial Proteases Hydrolysis

The gelatin extracted from the bone of Indonesian Pangasius sutchi was hydrolyzed using two proteases, namely protease Lactobacillus plantarum S31, which isolating from bekasam (an Indonesian fermented fish product) and flavourzyme (a commercial enzyme from Aspergillus oryzase). The concentrations of enzymes for hydrolysis were 1% and 6% based on enzyme/substrate [E/S] ratio. The bioactivity of the hydrolysates as an antioxidant was measured based on their capacity to inhibit 1,1-diphenyl-2-picylhydrazyl (DPPH). The ascorbic acid or vitamin C in the range 50-150 ppm was used as positive controls. The result showed that the bioactivities of all hydrolysates were increased compared to gelatin before hydrolysis. The hydrolysates have a percent of inhibition range that higher than the ascorbic acid. The hydrolysates of gelatin derived from the bone of Pangasius sutchi would be a potential source as raw material for bioactive peptides production with antioxidant activity.