Optimization of enzymatic pretreatments for maximizing olive oil recovery

Abstract

Enzymatic pretreatments to enhance oil recovery in olive oil extraction process were investigated. The laboratory scale mechanical method consisting of crushing of olive fruits in fruit mill, malaxation in oil press for 60 min followed by pressing in hydraulic press at 15 ton/m² for 30 min and finally centrifugation of oil-water mixture (5000 rpm for 20 min) to separate oil was optimized. Combination of pectinase + cellulase (1:1) @ 0.05% resulted in maximum oil recovery and minimum loss of oil in cake compared to individual enzymes (pectinase, cellulase and pectinaseCCM) even at higher concentrations. The oils obtained with enzymatic treatments had relatively higher natural antioxidants (total phenols), slightly higher oil clarity, and lower free fatty acids and peroxides. All the quality parameters of olive oil extracted with or without enzymes were well within the specifications of Indian Food Laws and Codex Alimentarius. Enzymatic pretreatments significantly improved oil recovery and did not exert any adverse effect on the nutritional and pharmaceutical quality of the oil.