and the optimum conditions of time, temperature and pH for obtaining maximum RPs yield were calculated as 69.48 min, 45.36 ◦ C and 4.58, respectively. Under these optimized conditions, maximum RPs yield was predicted to be 0.67% (w/w). The maximum RPs yield obtained experimentally using the optimized conditions was 0.66% (w/w), which was con- sistent with the predicted value obtained using a response surface methodology regression analysis.