Supercritical extraction of sunflower oil: A central composite design for extraction variables.

Supercritical carbon dioxide (SC-CO2) extraction of sunflower seed for the production of vegetable oil is investigated and compared to conventional methods. The effects of extracting variables, namely pressure, temperatures, particle size, SC-CO2 flow rate and co-solvent, on SC-CO2 extraction are investigated. The maximum yield for sunflower oil is found to be about 54.37 wt%, and is obtained when SC-CO2 extraction is carried out at 80 °C, 400 bar, 0.75 mm particle and 10 g/min solvent flow with 5% co-solvent. A central composite design is used to develop the model and also to predict the optimum conditions. At optimum conditions obtained based on desirability function, 80.54 °C, 345 bar, 1.00 mm, 10.50 g/min and 7.58% ethanol, SC-CO2 extraction has performed and found that extraction yield dropped by 2.88% from the predicted value. Fatty acid composition of SC-CO2 and hexane extracted oil shows negligible difference and found high source of linoleic acid.