Extraction of γ-Oryzanol from defatted rice bran using supercritical carbon dioxide (SC-CO2): Process optimisation of extract yield, scale-up and economic analysis

Abstract

Sustainable agricultural practises ensure production of quality products having negligible environmental impacts replacing conventional techniques. Supercritical carbon dioxide (SC−CO2) extraction, a replacement to flammable, toxic, non-ecological solvent extraction was carried out in this study to extract γ-oryzanol, a potent bioactive ingredient, from defatted rice bran. The response surface methodology was applied to optimize the handling parameters such as temperature, pressure and CO2 flow rate . Extraction of γ-oryzanol is investigated at low pressures (such as 15, 20 and 25 MPa) compared to previous studies. The highest (optimum) yield of γ-oryzanol was 36,000 mg.kg−1 at 10 w/w% of ethanol as co-solvent and the corresponding temperature, pressure and CO2 flow rate were 48.9 °C, 23.9 MPa and 29.8 g.min−1, respectively. The techno-economic assessment using Aspen plus software evaluated the return of investment of the plant processing 3000 tonnes of rice bran per year accounts for a net present value almost double the investment cost having a payback period of around 5 years.