EXTRACTION OF MILK-FAT IN HIGH-PRESSURE SOLVENTS

Extraction of milk fat in several high pressure solvents was compared. Solubility of milk fat in supercritical (SC) ethylene and liquid prop ane was compared to previous results in SC CO2. At the same operating conditions (temperature and pressure), solubility of milk fat was high er in SC ethylene than in CO2, although levels generally remained belo w 5% (w/w), This resulted in significantly higher solubility in SC eth ylene when compared at equivalent solvent density, Very little fractio nation of milk fat occurred in liquid propane over the range of pressu res (3.45 to 5.52 MPa) and temperatures (30 to 90C) studied. Below 77. 5C and 2.76 MPa, liquid propane and milkfat were miscible, while a sli ght fractionation was observed above these conditions. A high pressure sight-gage apparatus was used to visually confirm these conditions fo r separation.