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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 can easily be extracted chemically (using hexane, ethanol, acetone, petroleum ether, benzene, etc.) or mechanically. It is usually available from sources such as soy beans, 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. Lecithin is a multi-purpose food ingredient that primarily functions as an emulsifier and dispersing agent. Lecithin’s surface-active property can be attributed to its chemical composition: a complex mixture of phospholipids, glycolipids, carbohydrates and triglycerides. As such, lecithin interacts well with other substances, such as proteins, lipids and carbohydrates. Lecithins, the Natural Choice of Emulsifier! Lecithins offer mankind unlimited applications in not only food but also animal feed as well as many industrial applications. In order to appreciate what lecithins can do in practice it facilitates the understanding by first reviewing the chemical nature of lecithins, they way they are extracted,refined and processed from nature and the basic properties that are generated by these process steps.The lecithin molecule has a unique structure that allows formation of rigid multilayer membrane structures, often referred to as “liquid crystal mesophases”. Nature use this property for the membrane structure of all living cells and thus lecithin occur in plants and animals. Very few other food emulsifiers occur in nature, but lecithin is the one-and-only emulsifier that is used directly as a dietary supplement and eaten by the spoonfuls, sprinkled on foods or enjoyed as health beverages !The most economic source for commercial production of lecithin are the seeds from soya beans,sunflower- and rape seeds.
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