A kinetic study of phospholipid extraction by degumming process in sunflower seed oil

During the refining process of vegetable oils (degumming), phospholipids ar e eliminated by thermal treatment with water (hydratable phospholipids, HP) and other degumming agents such as phosphoric acid, citric acid, or acid m ixtures (nonhydratable phospholipids, NHP). Samples of pressed crude sunflo wer oils were degummed with water and acids, and the corresponding pellets (gums) and supernatant oils were obtained by centrifugation. During the wat er degumming process, a decrease of more than 98% in the phosphatidylcholin e (PC) content was achieved in 5 min; phosphatidylethanolamine (PE) was the most difficult compound to be removed. Phosphatidylserine, phosphatidic ac id, and phosphatidylinositol (PI) presented an intermediate behavior. The o ptimal contact time for quantitative extraction of the most important HP (P C, PI, and PE) in crude sunflower oils was 35 min. For acid treatments, a r apid elimination of the residual levels of PC was registered (5 min); the o ptimal contact times for the quantitative removal of the NHP were 35 min fo r phosphoric acid and acid mixture, and 25 min for citric acid. Taking into . account that PE was the most difficult component to be removed, its level could be used as a monitor to evaluate the efficiency of the degumming pro cess.