A simplified model to describe the kinetic behavior of supercritical fluid extraction from a rice bran oil byproduct.

The mathematical modeling of the overall extraction curve (OEC) was performed using experimental data of supercritical flu id extraction (SFE) fro m a byproduct of the rice bran oil (RBO) industry. The soapstock derived fro m the RBO deacidification process was used as raw material because it contains a significant amount of γ-ory zanol, wh ich is a valuable natural antio xidant. The main goal of this work was to describe the OEC by a simplified model using the kinetic data obtained for the SFE fro m rice bran oil soapstock (RBOS). The global y ield isotherms (GYI) were used to select the best operational conditions (temperature and pressure) based on the extract ion yield and the γ-oryzanol content of the obtained extract. The OEC was fitted to four simplified models and the kinetic parameters which characterize the constant extraction rate (CER) were estimated. The highest values for the extraction yield (12.5 %, w/w), the γ-oryzanol content (16 %, w/w), and the γ-ory zanol recovery rate (55 %, w/ w) were found at 30 M Pa/333K. The proposed spline model presented the best fit to experimental data and quantitatively described the OEC. The estimated time span of the CER period (tCER) was 70 min and the corresponding solvent to feed (S/F) ratio and extraction yield were 23 and 9.4 %, respectively.