Effect of soybean pretreatment on the phospholipid content in crude and degummed oils

The influence of heating temperature, initial moisture and grinding or flaking of soybeans on the phospholipid extraction with chloroform/ethanol mixture (volume ratio 2:1) and hexane, as well as the effect of soybean pretreatment on water degumming of crude oil were investigated. The content of phospholipids in oil decreased with increased heating temperature and with decreased initial soybean moisture. The steam treatment of soybean (ground and flaked) prior to extraction increased the content of phospholipids in oil. Extraction with chloroform/methanol mixture yielded 2-3 times more phospholipids than extraction with hexane. Soybean pretreatment elevated or lowered the phospholipid level in extracted oil, similarly to hexane extraction. Under the same processing conditions, the oil obtained from soybean flakes had a higher phosphorus content than the oil from ground soybeans. The results of laboratory water degumming show that the phosphorus content of the degummed oil from unpretreated soybean is higher than that from pretreated seed. A higher content of hydratable phospholipids was retained in the degummed oil obtained from unpretreated soybeans.