Phase Equilibria and Distribution Coefficients of δ-Lactones in Supercritical Carbon Dioxide

A static method was used to measure the solubilities and distribution coefficients of δ-lactones (pure), inherent (natural levels) δ-lactones of anhydrous milk fat (AMF) and fortified (added) δ-lactones in AMF in supercritical carbon dioxide (SC-CO₂) at 40°C with pressures of 5–30 MPa. At 40°C distribution coefficients of δ-lactones increased with pressure and exhibited molecular weight-dependency. Using experimental data, a mathematical model based on thermodynamic equilibria and material balance was developed and used to predict the distribution of inherent δ-lactones of AMF in a continuous SC-CO₂ extraction system. At 24.1 MPa/40°C column conditions, AMF was separated into a raffinate and 5 fractions. Predicted δ-lactones distribution coefficients in the raffinate and extract were in good agreement with experimental data.