Enzymatic deacidification of the rice bran oil and simultaneous preparation of phytosterol esters-enriched functional oil catalyzed by immobilized lipase arrays

Abstract

Rice bran oil (RBO) is a great and important vegetable oil resource, but usually contain high content of free fatty acids (FFAs). Phytosterol esters are functional lipids possessing hypocholesterolemic activity. In this study, Candida rugosa lipase (CRL) was immobilized on the octyl-functionalized ordered mesoporous silica (C8-OMMs) to obtain immobilized CRL arrays (CRL@C8-OMMs). The resulting CRL@C8-OMMs arrays showed much better thermal stability and reusability in comparison to free CRL. The deacidification and simultaneous preparation of functional oil rich in phytosterol esters (PEs) was successfully achieved by enzymatic esterification of high-acid RBO with phytosterol. The contents of FFAs and PEs were below 2.3% and above 84.7%, respectively. Repeated reaction tests indicated that CRL@C8-OMSs arrays could be used 11 times with 80.7% of its original catalytic activity still retained. The strategy could not only take advantage of the high-acid oils resources, but also product PEs-enriched functional oils.