Selective extraction of phosphatidylcholine from lecithin by supercritical carbon dioxide/ethanol mixture

Selective extraction of phosphatidylcholine (PC) from deoiled soybean lecithin using supercritical fluid (SCF) mixtures of carbon dioxide (CO2) and ethanol was studied at moderate pressures. Temperature was varied between 60 and 80 degreesC at pressures of 17.2 and 20.7 MPa. Ethanol was added as co-solvent to supercritical CO2 at the levels of 10 and 12.5 wt%. Constant rate of extraction of the individual phospholipids (PL) was observed for 150 min during which the extractions were carried out. Pressure and ethanol fraction had a positive effect on the selective extraction of PC, whereas temperature had a negative effect. Under all the conditions studied, the extracts were mainly composed of PC while the extraction of the other PL was very low. Extraction at 60 degreesC and 20.7 MPa with 10 wt% ethanol/90 wt% CO2 SCF mixture resulted in 95% selectivity to PC.