Isolation of γ-oryzanol through calcium ion induced precipitation of anionic micellar aggregates

Abstract

A simple method for the isolation of γ-oryzanol from rice bran acid oil has been developed. The basis of the present isolation protocol is calcium ion induced precipitation of anionic micellar aggregates. Rice bran acid oil, a byproduct of rice bran oil processing industries, is subjected to conventional vacuum distillation to remove free fatty acids. Aqueous alkaline hydrolysis of the resultant residue, upon dilution with water, produces anionic micellar aggregates containing solubilized γ-oryzanol. Addition of calcium ions to this aqueous micellar aggregate induces instant coprecipitation of the calcium salts of the fatty acids and the aggregate-associated γ-oryzanol. The dried precipitate is extracted with ethyl acetate. Ethyl acetate is evaporated from the extract, and γ-oryzanol is purified from the residue by silica gel column chromatography. Experimental details for the isolation and characterization procedure are described. The present method will give ready access to the physiologically beneficial and value-added pharmaceutical product γ-oryzanol.