Crude papain was extracted from papaya latex under various conditions. Extraction conditions of crude papain were optimized by the response surface methodology (RSM). Extraction yield of papain was affected by concentration of $NaHSO_3$, extraction time and pH. Three independent factors were chosen to determine their effects on the various responses and the function was expressed in terms of a quadratic polynomial equation, which measures the linear, quadratic and interaction effects. According to the results of RSM, the stationary point for quantitatively dependent variable was found to be the maximum point for extraction yield. Optimum conditions of papain extraction were 4% of $NaHSO_3$, 120 min of extraction time and pH 7.6. Under these conditions, 793.16 mg of papain per g latex was extracted from papaya latex.
papain;extraction;response surface methodology;optimization