Optimization of Supercritical Carbon Dioxide Extraction of Flaxseed Oil Using Response Surface Methodology

The optimal conditions for the supercritical carbon dioxide (SC-CO2) extraction of flaxseed oil from flaxseed were determined using response surface methodology (RSM). A second-order regression for rotation-orthogonal composite design was used to study the effects of three independent variables: extraction pressure (MPa), extraction temperature (oC) and CO2 flow rate (L/h) on the yield of flaxseed oil. The independent variables were coded at five levels and their actual values selected on the basis of preliminary experiments. The results indicated that the yield of flaxseed oil was beyond 29% at a probability of 95% in the range of extraction pressure: 38.6-42.3 MPa, extraction temperature: 52.3-57.0 oC, and CO2 flow rate: 27.8-31.2 L/h. The optimal extraction conditions were extraction pressure of 41 MPa, extraction temperature of 56 oC and CO2 flow rate of 31 L/h according to the analysis of response surface. In this condition, the experimental yield of flaxseed oil was 29.96%, which was close to the predicted value of 30.52%.