Characterisation and Process Development of Supercritical Fluid Extraction of Soybean Oil

This work describes and analyses the extraction of soybean oil using supercritical carbon dioxide as a solvent from the point of view of both operative method and pre-treatment of the raw material. The best conditions for soybean oil extraction were obtained at a pressure of 300 bar, a temperature of 40 � C and a solvent flow rate of 1.8 L/min at STP. The yields obtained using the supercritical fluid under the best operating conditions were similar to those obtained byconventional extraction methods using hexane as the solvent (19.9 %w/w.); furthermore, the qualityof oil extracted bythe supercritical fluid was higher (acidity, 0.8). The fatty acid composition of the soybean seed oil extracted by supercritical fluid was particularlyrich in unsaturated fattyacids, particularlylinoleic acid (51.8%). For these reasons, the soy bean seed oil extracted using supercritical carbon dioxide could compete with that obtained bythe conventional process, since the oil refinement stages are simplified significantlyand the solvent distillation stage is completelyremoved, which are the two most costlyprocessing stages in terms of energyconsumption.