Thermal gradient deacidification of crude rice bran oil utilizing supercritical carbon dioxide

The effect of isothermal and temperature gradient operation of a supercritical fluid fractionation column on the composition of rice bran oil (RBO) fractions has been studied. Application of a temperature gradient along the column was found to be beneficial in reducing the triacylglycerol (TAG) lost in the extract fraction. Utilization of higher temperature in the stripping section improved free fatty acid (FFA) removal from crude RBO. FFA acid content of the extract increased, and TAG content decreased with respect to time during the fractionation runs. Increasing the CO2 flow rate from 1.2 to 2 L/min did not affect the extract composition significantly. By using the above approach, it is possible to obtain RBO fractions with similar total sterol ester content [similar to 23 high-performance liquid chromatographic area (HPLC) %, ferulic plus fatty acid esters] to that of the commercially available sterol ester-enriched (ca. 21 HPLC area % fatty acid esters) margarines/spreads.