Comparative studies on the antioxidant potential of hydrolysates of <i>Mormyrus rume</i> muscle protein

Abstract

This study determined the degree of hydrolysis of Mormyrus rume muscle proteins by digestive proteases and the antioxidant potential of the hydrolysates produced was evaluated. The proteins were extracted with distilled water adjusted to neutral pH. The proteases used include trypsin, chymotrypsin and pepsin and the degree of hydrolysis was determined using trichloroacetic acid precipitation method. The antioxidative activities of the hydrolysates were evaluated using different in-vitro antioxidant assay methods such as 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging, hydrogen peroxide scavenging, metal chelating capacity and reductive potentials. Degree of hydrolysis was generally low and ranges between 17.68% and 32.20% with pepsin given the highest degree of hydrolysis. The protein hydrolysates obtained with trypsin exhibited the highest antioxidant activities when assessed with metal chelating activity assay with half maximal inhibitory concentration (IC ) of 0.32 ± 0.01 mg/ml; hydrogen peroxide scavenging assay with IC of 0.18 ± 0.01 mg/ml 50 50 and reductive potential of 0.41 ± 0.002 units at the highest concentration tested (1.0 mg/ml). Pepsin-produced hydrolysates showed the highest DPPH radical scavenging potential at all concentrations with IC of 0.35 ± 50 0.003mg/ml. The study concluded that the hydrolysates produced contain bioactive peptides which possessed significant amount of antioxidant activities, which may be a promising health promoting agent if isolated.

Keywords: Hydrolysates, Pepsin, Trypsin, Chymotrypsin, Antioxidant, Enzyme, Mormyrus rume.