Effect of Physicochemical Parameters On Antioxidant Activity of Hydrolysed Tilapia Protein

Abstract

-Marine-derived proteins and their hydrolysed peptide fractions exhibit high bioactivity due to their unique amino acid composition distinct from terrestrial protein sources. This study examined the effect of enzyme concentration, temperature, and hydrolysis time on the antioxidant activity of papain-hydrolysed tilapia protein. Protein hydrolysates were prepared by enzymatic hydrolysis using papain and purified by gel filtration chromatography, following standard analytical protocols. Response surface methodology (RSM) based on a Box-Behnken design was used to model the influence of enzyme concentration, temperature, and hydrolysis time on antioxidant activity (DPPH radical scavenging), across 15 experimental runs. DPPH scavenging activity ranged from 51.86% to 92.17% across the design space. Maximum antioxidant activity occurred at an enzyme concentration of 4%, temperature of 60 °C, and hydrolysis time of 5 h. The temperature × hydrolysis time interaction (AC) was non-significant (p > 0.05), indicating that the two variables exert independent main effects rather than acting synergistically. The model followed an additive response topology; whereby peak antioxidant activity is predicted when temperature and hydrolysis time are set concurrently at their individually optimal values. These findings demonstrate that enzyme concentration, temperature, and hydrolysis time independently govern the antioxidant activity of papain-hydrolysed tilapia protein, providing a basis for optimising hydrolysis conditions to maximise bioactive peptide yield.