Selective extraction of phospholipid mixtures by supercritical carbon dioxide and cosolvents

To optimize and enhance the value of a previously developed supercritical fluids (SF) process for removing oil from soybean flakes, we devised a two-step, sequential scheme for extraction of oil and phospholipid-containing fractions using SC-CO2 alone or with ethanol. PLs were selectively removed from the flakes using the SC-CO2/ethanol mixture. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were more readily solubilized in the SC-CO2/cosolvent mixtures than were phosphatidylinositol and phosphatidic acid. The extent of recovery of PC and PE was a function of the molar fraction of cosolvent. Some fractionation of constituent phospholipids could be achieved by varying the molar fraction of ethanol. The extracts from the SF process were characterized by inductively coupled plasma spectroscopy (ICP) and HPLC with evaporative light scattering detection.