Phospholipids occur naturally throughout the plant and animal world, but in much smaller amount than triglycerides.
They are most abundant in egg yolks, liver, soybeans, wheat germs and peanuts.
Phospholipids may be removed by separation of two phases; from example, if butter is melted and filters, the pure oil thus obtained is free from phospholipids.
After refining of oils, neutralization, bleaching, and deodorization, the phospholipids content is reduced to vitally zero.
The amount of phospholipids associated with the glycerides of seeds is usually small, and expression, purification and refining of the oil remove most of this amount.
The phospholipids removed from soybean oil are used as emulsifiers in certain foods, such as chocolate.
Other favorable functions of phospholipids including ingredients for food, cosmetics, agriculture and pharmaceuticals.
Soybean phospholipids contain about 35 percent lecithin and 65 percent cephalin.
The fatty acids composition of phospholipids is usually different from what that of the oil in which they are present. The fatty acids make the phospholipids soluble in fat; the phosphate group enables them to dissolve in water.
The acyl groups are usually more saturated than those of the triglycerides.
Phospholipids of many vegetables oils contain two oleic acid residues.
The phospholipids of milk do not contain the short chain fatty acids found in milk fat triglycerides and they contain more long chain polyunsaturated fatty acids than the triglycerides.
The fat globules of milk are each surrounded by a thin protective layer, usually called a milk fat globule membrane.
This membrane is comprised of three major phospholipids species – sphingomyelin. phosphatidyl choline and phosphatidyl ethanolamine.
Phospholipids in food
