Supercritical carbon dioxide extraction of rice bran oil and column partition fractionation of 7-oryzanols

摘要

This work studies how pressure and temperature affect supercritical carbon dioxide extraction of rice bran oil from powdered rice bran,followed by the concentration and isolation of 7-oryzanols by column partition purification.The two purest 7-oryzanols(>98 wt.%)were isolated from reagent chemical 7-oryzanols by preparative reverse-phase high-pressure liquid chromatography.In searching for a suitable range of extraction conditions,supercritical extraction at 350 bar and 313 K yielded 17.5% oil and the extraction efficiency of 7-oryzanols was 84.9%,using 1200 g of carbon dioxide over 4 h.Finally,supercritical extractions at pressures from 250 to 350 bar and at temperatures from 313 to 333K were chosen based on the response surface methodology to determine their effects on concentration of 7-oryzanols in the extracted oil.Pressure proved more significant than temperature in increasing the concentration of 7-oryzanols.A significant amount of the purest oil that contained 37.0 wt.% 7-oryzanols was obtained following a normal-phase medium-pressure column partition fractionation of the extracted oil.