Surfactant-Assisted Aqueous Extraction of Soybean Oil From Soybean and Recovery of Oil From Skim

Aqueous extraction processing (AEP) is a safer and more environmentally friendly oil extraction method than conventional solvent extraction. SDS and phospholipid were added as emulsifiers to the extraction mixture to test their effect on extraction yield of protein and oil during AEP. It was found that the addition of SDS to the extraction increased the amount of oil released from the insoluble fraction of the soybean; however, this was not true for phospholipid. A protein-rich skim fraction resulting from AEP was isolated and analyzed by differential scanning calorimetry to determine the effect of the emulsifiers on the native protein conformation. The addition of phospholipid did not affect the native conformation of either glycinin or β-conglycinin; however, SDS-assisted extraction resulted in the denaturation of β-conglycinin. Efforts to break the skim emulsion and induce aggregation of oil droplets to form a cream via electrostatic shielding with electrolyte, exclusion aggregation with a polyelectrolyte, a secondary extraction performed on the skim fraction were unsuccessful.