sible oil losses in the Illes’s extraction process at higher CO2flowrate (1–1.5 L/min). Because they collected the better oil recovery ofextracted oil at the lower CO2flow rate (2–4 mL/min) in the collec-tion vessel. The cross–over phenomenon is due to the competingeffects of reduction in the scCO2density and enhancement in thefatty acids volatility, which accompany the temperature rise. Thisphenomenon is traditionally observed in the high compressibilityregion of supercritical solvents. The density of scCO2is increasedwith decreasing temperature at a constant pressure, and hence theoil solubility increases with the density effects. However, the scCO2density alone does not give the complete explanation of solubilityenhancement. Another factor, the volatility of oils is also respon-sible for contributing to the oil solubility behaviors. As a matter offact, the crossover phenomenon is explained by the relative influ-ence of the density effect and the volatility effect. The extractionyield was determined as 16.5 g oil/100 g dry solid in the separationprocess made with Soxhlet extraction. This specified yield can bereached at 150 min during the supercritical CO2extraction madeunder the conditions of 30 MPa, 40◦C, 0.75 mL/min and at 90 minin the cases where 5%vol. ethanol is used as the entrainer. No sig-nificant change is determined in the profile of fatty acids in thespecified extraction processes. As a result of nonlinear regressionanalyses, it is seen that the apparent solubility values of rose hipseed oil in supercritical CO2show a strong consistency (r2≥ 0.990)with Chrastil, del Valle–Aguilera, Adachi–Lu and Sparks solubilitymodels.