Extraction kinetics modeling of wheat germ oil supercritical fluid extraction

Abstract

The aim of this study was the optimization of supercritical fluid extraction (SFE) of wheat germ oil obtained as by-product from industrial mill. Extraction kinetics modeling and response surface methodology (RSM) were used for that purpose. SFE was performed with broadening Box-Behnken experimental design, where pressure (250–350 bar), temperature (40–60°C), and CO2 flow rate (0.2–0.4 kg/hr) were used as independent variables. Five empirical kinetic equations were successfully utilized for modeling of SFE. Model IV (Kandiah and Spiro model) provided the best fit with experimental data, according to statistical parameters (R2, sum of squared errors and average absolute relative deviation). Furthermore, initial slope calculated from this model was used as a response variable for RSM optimization. It could be concluded that SFE should be performed at elevated pressure (350 bar) and CO2 flow rate (0.4 kg/hr), while temperature should be held at a lower level (40°C) in order to achieve a maximal initial slope. Practical applications Optimization and modeling of industrial processes are crucial factors that will determine its efficiency and profitability. This research provided information about modeling of green and environmentally friendly extraction technique, that is, SFE, which could be successfully utilized for recovery of valuable oil from food industry by-product, that is, wheat germ. Commonly used empirical models were successfully applied for modeling of extraction process and influence of SFE factors on model parameters was determined providing information about mass transfer phenomena during extraction. Further investigation provided determination of the highest initial extraction rate constant which could be applicable for optimization of industrial scale processes.