Optimization of Supercritical CO2 Extraction of Safflower Seed Oil Using Response Surface Methodology

Abstract

The present study examined extraction of safflower seed oil by using supercritical carbon dioxide. Response surface methodology was used to evaluate the effects of the process parameters, namely pressure, temperature and extraction time on the yield of safflower seed oil. The quadratic terms of time (p < 0.01), temperature (p < 0.001) and pressure (p < 0.001), interaction between time and pressure (p < 0.001), as well as time and pressure (p < 0.001) showed significant effect on the safflower oil yield in the present model. Optimum yield of safflower seed oil was predicted as 26.47 % at pressure of 450 bars, temperature 68.49 °C and extraction time of 30 min. Colour, acid value, saponification value and induction time of safflower seed oil extracted using supercritical CO2 were compared with that obtained by solvent extraction. Minor differences were found in all the studied parameters of the oils extracted by the two methods. Acid value of oil extracted using supercritical CO2 was approximately five times lower than the value obtained for the oil from solvent extraction. However, a slightly shorter induction period was recorded for the supercritical CO2 extracted safflower seed oil as compared to the solvent extracted oil at all the studied temperatures i.e., 120, 140, 160 and 180 °C. Minor differences were observed in the fatty acid composition of the oils extracted using two methods.