A process line for the production of raffinated rice oil from rice bran

Rice bran is a by-product of rice processing, obtained through the polishing of the rice grain. It presents a considerable high oil content (between 20 and 25%) and it is considered an excellent source of nutritionally beneficial compounds, such as tocotrienols, tocopherols and sterols. Batch supercritical fluid extraction (SFE) of rice bran with CO2 was performed at different operational conditions (from 100 to 400 bar, 50 and 60 °C) and the extract yields were in the range of 20%. The next step corresponded to the deacidification of the obtained oil in a countercurrent (CC) column, where the experiments were carried out at 250 bar and 67 °C. The results have shown that the free fatty acids (FFA) removal from the crude rice bran oil (RBO) was successfully achieved. Deacidified RBO with <1% FFA could be obtained by applying the described process. To conclude this work, an industrial process has been proposed which couples batch SFE of rice bran with CC-SFE of the extracted oil obtained, in order to isolate the undesired FFA fraction from the raffinated oil, composed mainly by triglycerides (TG).