Commercial lecithin is made by degu

Commercial lecithin is made by degumming crude vegetable oilwith water, separating the aqueous gum phase from the oil andthen drying this phase. It has been known for a long time thatwater degumming does not remove all phospholipids from theoil. However, discovering why some phospholipids are hydra-table whereas others are not turned out to be difficult. After all,the same phospholipids that are present in water degummed oilalso occur in lecithin.In the 60s it was found that for some phospholipids, thehydratability depends on their counter cation. Accordingly, thecalcium and magnesium salts of phosphatidic acid (PA) are non-hydratable whereas its potassium salt is fully hydratable. Conse-quently, removing the non-hydratable phospholipids (NHP)from oil amounts to converting the alkaline earth salts to alkalisalts and various processes have been developed to do just that.Most of these processes start by treating the oil to be degummedwith an acid that is stronger than PA and can therefore dislodgePA from its salts with formation of free, non-dissociated PA.Because this PA has no charge, it is hardly hydrophilic. The bestway to make it hydrophilic and cause it to move into the aque-ous phase is by raising the pH which causes the acid to dissociateand obtain a negative charge. This is the principle of the acidrefining process [1].However, to prevent the alkaline earth salt of PA from reform-ing the alkaline earth ions liberated by the degumming acidhave to be captured. The most effective reagent in this context isEDTA. It is so effective that it reacts directly with the NHP.Degumming acids like phosphoric acid and citric acid also cap-ture the alkaline earth ions they liberate