S. aethiopicum is a cultivated plant, known over the West and Central Africa. Its seeds have proteinases which possesses activity (MCA). In this work, response surface methodology was used to optimize the extraction of milk-clotting enzyme (MCE) according to its adequacy to be employed as substitute of rennin. Box-Behnken design was applied to evaluate the effects of three independent variables, namely NaCl concentration, extraction duration and pH on extraction efficiency (EE) of MCE. Results indicated that the actual data were satisfactorily fitted into second-order polynomial model. The independent variables, the linearity and quadratics of NaCl concentration, extraction duration and pH as well as interactions between NaCl concentration and extraction duration had a significant effect on EE of MCE. The optimal conditions to obtain the highest extraction efficiency of MCE from S. aethiopicum seeds were 5.5 % (w/w) of NaCl concentration, 27 h of extraction time and pH 5.3. Under these conditions, the experimental values agreed with the predicted ones. The results in this work were helpful for preparation of crude enzymes from S. aethiopicum plant in view to use it in cheese technology.
