PROBLEM TO BE SOLVED: To make a membrane degumming process industrial by adding a lecithin enriched with phosphatidyl choline, and water to a vegetable oil before degumming through a membrane to enhance its phosphatide rejection and permeation flux without adding an electrolyte.
SOLUTION: As a natural vegetable oil, a soy bean oil, a rapeseed oil, a palm oil and a sunflower oil can be mentioned for example. A suitable membrane is a hydrophobic polyethylene or polytetrafluoroethylene membrane having a pore size of 30-1,000 nm. A lecithin enriched with phosphatidyl choline is obtained by evaporating ethanol from the ethanol-solved fraction of the acetone-unsolved fraction of a soy bean oil lecithin. For a batch process, this is added to a natural vegetable oil. For a continuous process in which a condensed oil is circulating, the lecithin is added to a natural vegetable oil or the condensed oil before re-separation.