Supercritical carbon dioxide extraction and deacidification of rice bran oil

This study examined pilot-scale extraction and lab-scale deacidification of rice bran oil by using supercritical carbon dioxide (SC-CO2). Two purest gamma-oryzanols ( gamma-oryzanols) (>98 wt%) were initially obtained by preparative reverse-phase high-performance liquid chromatography. Supercritical carbon dioxide extraction at 300 bar and 313 K from 1.03 kg powdered rice bran indicated a total yield of oil of 15.7% with a free fatty acids content of 3.75%, obtained from 20.5 kg of carbon dioxide in 8 h. In the SC-CO2 deacidification, pressure ranged from 200 bar to 300 bar, temperature ranged from 343 K to 363 K and consumption of carbon dioxide ranged from 900 g to 2700 g: the efficiency of removal of free fatty acids from 13 g extracted oil in deacidification at 250 bar and 353 K reached 97.8% using 2700 g of carbon dioxide. Finally, three-factor center composite scheme of response surface methodology was employed in designing a SC-CO2 deacidification system, which demonstrated that the pressure and consumption of carbon dioxide are significant in retaining triglycerides and in removing free fatty acids from rice bran oil. (C) 2008 Elsevier B.V. All rights reserved.