Extraction from oleaginous seeds using supercritical CO2: Experimental design and products quality

An experimental design has been built in order to study the influence of different parameters on the oil extraction yield for two types of seeds (rape and sunflower) using supercritical CO2: pressure (15–45 MPa), temperature (35–75 °C), CO2 flow rate (8–19 kg h−1) and extraction duration (20–120 min). Extraction yields are between 0.3% and 89.8%, indicating that the experimental design covers a large range of results. Acidic and phosphorus contents in the oil and protein content in the residual cake have been done. The results indicate that pressure and extraction duration are the most influencing parameters together with temperature in the case of rape seeds. Thermodynamic effects (solubility) and kinetic effects (mass transfer depending on the seeds) have been evidenced. The selectivity of pure supercritical CO2 has been shown: any phospholipid is extracted. In addition to selectivity, another interest of the process is the purity of the products recovered, totally free from organic solvent.