Lecithin
From Wikipedia, the free encyclopedia
Lecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids (e.g., phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol).
Lecithin was first isolated in 1846 by the French chemist and pharmacist Theodore Gobley.[1] In 1850, he named the phosphatidylcholine léchithine.[2] Gobley originally isolated lecithin from egg yolk—λέκιθος (lekithos) is 'egg yolk' in ancient Greek—and established the complete chemical formula of phosphatidylcholine in 1874;[3]
in between, he had demonstrated the presence of lecithin in a variety
of biological matters, including venous blood, bile, human brain tissue,
fish eggs, fish roe, and chicken and sheep brain.
Lecithin can easily be extracted chemically (using hexane, ethanol, acetone, petroleum ether, benzene, etc.) or mechanically. It is usually available from sources such as soybeans, eggs, milk, marine sources, rapeseed, cottonseed, and sunflower. It has low solubility in water, but is an excellent emulsifier. In aqueous solution, its phospholipids can form either liposomes, bilayer sheets, micelles, or lamellar structures, depending on hydration and temperature. This results in a type of surfactant that usually is classified as amphipathic.
Lecithin is sold as a food supplement and for medical uses. In cooking,
it is sometimes used as an emulsifier and to prevent sticking, for
example in nonstick cooking spray.
Dietary supplement
Because it contains phosphatidylcholines, lecithin is a source of choline, an essential nutrient.[13][14]
Clinical studies have shown benefit in acne, in improving liver
function, and in lowering cholesterol. 17] La Leche League recommends its use to prevent blocked or plugged milk ducts which can lead to mastitis in breastfeeding women.[18]
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