The phase behavior of systems of supercritical CO2 or propane with edible fats and a wax

The phase behavior of the systems CO2/Rp70 (hardened rapeseed oil), CO2/tripalmitin, CO2/hydrogenated castor oil (HCO) and propane/Rp70 was studied experimentally according to the synthetic method using a Cailletet apparatus.For the CO2/Rp70 system bubble-point curves and solid–liquid curves were determined for CO2 concentrations from 5 up to 30 wt%. A comparison was made between the phase behavior of these systems and the phase behavior of the systems propane/tripalmitin. The solubility of propane in tripalmitin is markedly higher as compared to the one of CO2 and tripalmitin.For the propane/Rp70 system liquid–vapor curves, solid–liquid curves and liquid–liquid lower solution temperature curves were measured at propane concentrations from 10 up to 70 wt%. An increase in pressure or a decrease in temperature results in a higher solubility of carbon dioxide or propane in the fat melt. The measurements made it possible to predict qualitatively the phase behavior of the CO2/Rp70, CO2/tripalmitin, CO2/HCO and propane/Rp70 systems. For CO2/Rp70, CO2/tripalmitin, CO2/HCO systems a type III system was observed according to the classification of Van Konynenburg and Scott [7] and [8]. For propane/Rp70 a type IV phase diagram was observed.