Optimization of oil extraction from olive pomace using response surface methodology

Abstract

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%).