Lecithin is mostly a mixture of glycolipids, triglycerides, andphospholipids (e.g., phosphatidylcholine, phosphatidylethanolamine, andphosphatidylinositol). However, in biochemistry, lecithin is usuallyused as a synonym for pure phosphatidylcholine, a phospholipid that isthe major component of a phosphatide fraction, which may be isolatedfrom either egg yolk or soy beans from which it is mechanically orchemically extracted using hexane.

 

Lecithin is commercially available in high purity as a foodsupplement and for medical uses. It is especially used by vegetariansas a meat supplement.