Ohmic heating effect on enzyme assisted aqueous extraction of rice bran oil

Abstract

This study explored the improvement of oil recovery from rice bran by pre-treatment of ohmic heating prior to enzyme assisted aqueous oil extraction process (EAEP). A full factorial design was utilized to investigate the effect of electric field strength (OH450V, OH550V and OH650V), end point temperature (75, 85 and 95°C) and holding time (0, 5 and 10 min.). Incremental oil recovery through combined EAEP and ohmic heating ranged from 3.5% to 15.5% over EAEP alone. The electric field strength of OH650V at 95°C for 10 min holding time yielded maximum oil recovery (82%) for combined ohmic and EAEP treatment. The extracted oil was comparatively darker in colour than examined market edible rice bran oil. Pre-treatment of ohmic heating with EAEP on rice bran slightly increased the FFA in oil (1.89–2.24%) compared to market edible rice bran oil.