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. Lecithin can easily be extracted chemically (using hexane, ethanol, acetone, petroleum ether, benzene etc.) or mechanically. The lecithin can be obtained by degumming the extracted oil of seeds. It is a mixture of various phospholipids, and the composition depends on the origin of the lecithin. A major source of lecithin is soybean oil, with rapeseed, cottonseed, and sunflower oils rounding out the majority of commercial sources of lecithin. Lecithin has emulsification and lubricant properties, and is a surfactant. Applications include:
In the pharmaceutical industry, it acts as a wetting, stabilizing agent and a choline enrichment carrier, helps in emulsifications and encapsulation, and is a good dispersing agent. It can be used in manufacture of intravenous fat infusions and for therapeutic use.
In animal feed, it enriches fat and protein and improves pelletization.
In the paint industry, it forms protective coatings for surfaces with painting and printing ink, has antioxidant properties, helps as a rust inhibitor, is a colour-intensifying agent, catalyst, conditioning aid modifier, and dispersing aid; it is a good stabilizing and suspending agent, emulsifier, and wetting agent, helps in maintaining uniform mixture of several pigments, helps in grinding of metal oxide pigments, is a spreading and mixing aid, prevents hard settling of pigments, eliminates foam in water-based paints, and helps in fast dispersion of latex-based paints.
Lecithin can also be used as a release agent for plastics, an antisludge additive in motor lubricants, an antigumming agent in gasoline, and an emulsifier, spreading agent, and antioxidant in textile, rubber and other industries.
he nontoxicity of lecithin leads to its use with food, as an additive or in food preparation. It is used commercially in foods requiring a natural emulsifier or lubricant.
In confectionery, it reduces viscosity, replaces more expensive ingredients, controls sugar crystallization and the flow properties of chocolate, helps in the homogeneous mixing of ingredients, improves shelf life for some products, and can be used as a coating. In emulsions and fat spreads it stabilizes emulsions, reduces spattering during frying, improves texture of spreads and flavour release. In doughs and bakery it reduces fat and egg requirements, helps even distribution of ingredients in dough, stabilizes fermentation, increases volume, protects yeast cells in dough when frozen, and acts as a releasing agent to prevent sticking and simplify cleaning. It improves wetting properties of hydrophilic powders (e.g., low-fat proteins) and lipophilic powders (e.g., cocoa powder), controls dust, and helps complete dispersion in water.[4] Lecithin is the emulsifier that keeps cocoa and cocoa butter in a candy bar from separating. It can be used as a component of cooking sprays to prevent sticking and as a releasing agent. In margarines, especially those containing high levels of fat (>75%), lecithin is added as an 'antispattering' agent for shallow frying.