antioxidant activity optimization of gold stripe sardine (sardinella gibossa) protein hydro-lysate by rsm

protein hydro-lysate was prepared from gold striped sardine (sardinella gibossa) by papain. hydrolysis conditions (time, temperature, and enzyme activity) were optimized by response surface methodology (rsm) using a factorial design and anti-oxidative activity was the dependent variable. results of the total determination coefficient, adjusted r2 and predicted r2 indicating the validity of prediction model and the experiment error was very small. an enzyme activity to substrate ratio (x1), 2%; time (x2), 30 minute, and temperature (x3), 45 °c were found to be the optimum conditions for a higher dpph free radical scavenging activity (64.5%), using papain. according to amino acid analysis results and chemical score, methionine and isoleucine were the limiting amino acids in the hydro-lysate. the protein hydro-lysate tends to be a functional additive in food industries.