Density and volumetric expansion of carbon dioxide-expanded canola oil and its blend with fully-hydrogenated canola oil

Physical properties of lipids in equilibrium with high pressure carbon dioxide are influenced by CO2 solubility in the liquid lipid phase, which is a strong function of temperature and pressure. The experimental data of CO2 solubility in canola oil at 40 and 70 °C and its blend with fully-hydrogenated canola oil (FHCO) (30 wt%) at 70 °C up to 25 MPa were correlated using Peng–Robinson and modified Soave–Redlich–Kwong equations of state with quadratic and Panagiotopoulos–Reid mixing rules. The relative volumetric expansion of canola oil at 40 °C up to 20 MPa and 70 °C up to 25 MPa and its blend with FHCO (30 wt%) at 70 °C up to 25 MPa in equilibrium with CO2 was 41, 46, and 43%, respectively. The densities of canola oil at 40, 55, and 70 °C and its blend with FHCO at 70 °C in equilibrium with CO2 were measured up to 30 MPa and increased by 4.7, 4.3, 3.5, and 3.6% of its value at atmospheric pressure, respectively. The density of CO2-expanded lipids increased with pressure and decreased with temperature. Physical properties of CO2-saturated lipids are important for designing high pressure processes and especially here for better understanding of enzymatic interesterification of canola oil and FHCO using supercritical CO2, since these physical properties influence the reaction rates due to changes in mass transfer.

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► CO2 solubility in canola oil and its blend with fully-hydrogenated canola oil (FHCO) was successfully correlated using equations of state.
► Volumetric expansion of CO2-saturated canola oil at 40 °C increased with pressure up to 10 MPa and then reached a plateau at about 41%.
► Volumetric expansion of canola oil and its blend with FHCO at 70 °C increased up to 15 MPa and above that more slowly reaching 46 and 43%, respectively.
► Density of CO2-saturated canola oil increased with pressure and decreased with temperature.