Pilot Scale Extraction of Rice Bran Oil with Dense Carbon Dioxide

The purpose of this study was to measure the effects of temperature, pressure, and flow rate of dense CO 2 on its ability to extract, refine, and fractionate rice bran oil. Column beds (300 g) of rice bran were extracted with dense CO 2 at a flow rate of ∼2.5 kg/h, temperatures of 0−60 °C, and pressures of 17−31 MPa over a period of 6 h. The extracted total oil; the free fatty acid, α-tocopherol, sterols (campesterol, stigmasterol, β-sitosterol), and oryzanol components; together with moisture were measured at intervals. Extraction was almost complete in 6 h, and rates of extraction were consistent with saturation of the CO 2 with rice bran oil throughout most of the process. Extraction of the oil components was described by apparent partition coefficients between the oil and CO 2 phases. The observed differences in partition coefficients provide a basis for refining and fractionation of rice bran oil.