Effect of Subcritical Carbon Dioxide Extraction and Bran Stabilization Methods on Rice Bran Oil

The extraction of rice bran oil using the conventional organic solvent-based Soxhlet method involves hazardous chemicals, whereas supercritical fluid extraction is a costly high-temperature operating system. The subcritical carbon dioxide Soxhlet (SCDS) system, which operates at a low temperature, was evaluated for the extraction of rice bran oil in this study. In addition, rice bran that had been subjected to steam or hot-air stabilization were compared with unstabilized rice bran (control). The yields; contents of tocopherols, tocotrienols and oryzanol; fatty acid profiles; and the oxidative stabilities of the extracted rice bran oils were analyzed. The yields using hexane and SCDS extraction were approximately 22 and 13-14.5 %, respectively. However, oil extracted using the SCDS system contained approximately 10 times more oryzanol and tocol compounds and had lower free fatty acid levels and peroxide values compared with hexane-extracted oil. Overall, SCDS extraction of steamed rice bran represents a promising method to produce premium-quality rice bran oil.