Abstract: In this study, an acid hydrolysis procedure for preparing small peptides from Paphia undulate meat was proposed and optimized using response surface methodology (RSM). A quadratic regression model describing small peptide yield as a function of 3 variables was created based on a 5-level quadratic orthogonal rotation combination design, whose goodness of fit was 92.09%. The optimal hydrolysis conditions were found as follows: raw material-to-water ratio of 1:3, hydrochloric acid concentration of 6.4 mol/L, hydrolysis temperature of 92 ℃ and hydrolysis time of 5.3 h. Under the optimal conditions, the predicted and experimental recovery rates of small peptides were 84.04% and 82.21%, respectively. SDS-PAGE revealed that the smallest peptides in the resulting hydrolysate were less than 2 kD.

Key words: response surface methodology, Paphia undulata, acid hydrolysis, small peptide