Valorization of rice bran: modified supercritical CO2 extraction of bioactive compounds

Abstract

In this work, as a first step in a comprehensive strategy for the valorization of rice bran, the extraction of oil using supercritical CO2 and ethanol as cosolvent has been studied. The effect of extraction temperature (40 and 60 °C), pressure (30 and 40 MPa) and amount of ethanol used (0, 5 and 10%) has been considered. The quality extracted oil has been evaluated in terms of antioxidant activity, fatty acid profile and bioactive compounds such as phenolics, flavonoids, γ-oryzanols, and tocopherols content.

Results revealed that, using neat CO2, the best oil in terms of antioxidant activity was obtained at 40 °C and 30 MPa. However, the addition of ethanol as modifier significantly increased the amount of bioactive molecules extracted and hence the overall antioxidant activity of the oil, which was maximum at 40 MPa and 10% ethanol, regardless the temperature. The use of ethanol also affected the amount of fatty acids and γ-oryzanols extracted.