Membrane degumming of crude soybean and rapeseed oils

Membrane separation in edible oil processing is a potential area for energy savings. However, technical and operating-cost-related barriers have impeded the successful application of membrane separation in food processing. Studies were undertaken with soybean and rapeseed oils in a magnetically stirred flat-membrane batch cell with two types oi composite polymeric membranes at 3 MPa pressure and at a constant temperature of 40 degrees C, The membranes were NTGS-1100 and NTGS-2100, and used silicon as the active layer and polysulfone and polyimide as support layers, respectively. The membrane selectively rejected phospholipids, the content being less than 240 mg/kg in the permeate without any pretreatment or dilution of crude ail with organic solvent. Long-term studies up to 97 days with soybean oil at two different pressures, 2 and 3 MPa, showed that the rejection of phosphatides was above 96% in most permeates. The permeate flux remained nearly constant but must be improved.