Optimization of oil extraction from olive pomace using response surface methodology.

A statistical methodology, combining Plackett-Burman design with Box-Behnken design, was applied to optimize the oil extraction process from olive pomace using hexane as solvent. Plackett-Burman design was used in the first step to evaluate the effects of five independent variables on the oil extraction yield. Temperature of extraction, time of contact, solvent-to-solids ratio and moisture content of the olive pomace were identified as significant independent variables and were further optimized by using response surface methodology based on Box-Behnken design. The optimized conditions to maximize the yield were as follows: extraction temperature at 33 , contact time at 10 min, solvent-to-solids ratio at 3.5 mL/g and moisture content at 13%. The experimental value of the yield (5.98%) at these optimum conditions was found in perfect agreement with the value predicted by model (5.80%).