The definition of Fatty acids
Fatty acids are molecules that are long chains of lipid-carboxylic acid found in fats and oils and in cell membranes as a component of phospholipids and glycolipids. (Carboxylic acid is an organic acid containing the functional group -COOH.)
Fatty acids come from animal and vegetable fats and oils. Fatty acids play roles outside the body; they are used as lubricants, in cooking and food engineering, and in the production of soaps, detergents, and cosmetics.
Related terms about Fatty acids
Essential fatty acid: An essential fatty acid is a polyunsaturated fatty acid needed by the body that is synthesized by plants but not by the human body and is therefore a dietary requirement.
Free fatty acids: By-products of the metabolism of fat in adipose tissues.
Omega-3 fatty acids: Omega-3 fatty acids are a class of fatty acids found in fish oils, especially in salmon and other cold-water fish, that lowers the levels of cholesterol and LDL (low-density lipoproteins) in the blood. (LDL cholesterol is the “bad” cholesterol.)
Trans fatty acid: Trans fatty acids (trans fats) are made through hydrogenation to solidify liquid oils. They increase the shelf life of oils and are found in vegetable shortenings and in some margarines, crackers, cookies, and snack foods. Intake of trans fatty acids increases blood LDL-cholesterol (“bad” cholesterol) levels and raises the risk of coronary heart disease.
Analysis ofFatty acids
The chemical analysis of fatty acids in lipids typically begins with an interesterification step that breaks down their original esters (triglycerides, waxes, phospholipids etc.) and converts them to methyl esters, which are then separated by gas chromatography or analyzed by gas chromatography and mid-infrared spectroscopy.
Separation of unsaturated isomers is possible by silver ion (argentation) thin-layer chromatography. Other separation techniques include high-performance liquid chromatography (with short columns packed with silica gel with bonded phenylsulfonic acid groups whose hydrogen atoms have been exchanged for silver ions). The role of silver lies in its ability to form complexes with unsaturated compounds.
Industrial uses of Fatty acids
Fatty acids are mainly used in the production of soap, both for cosmetic purposes and, in the case of metallic soaps, as lubricants. Fatty acids are also converted, via their methyl esters, to fatty alcohols and fatty amines, which are precursors to surfactants, detergents, and lubricants. Other applications include their use as emulsifiers, texturizing agents, wetting agents, anti-foam agents, or stabilizing agents.
Esters of fatty acids with simpler alcohols (such as methyl-, ethyl-, n-propyl-, isopropyl- and butyl esters) are used as emollients in cosmetics and other personal care products and as synthetic lubricants. Esters of fatty acids with more complex alcohols, such as sorbitol, ethylene glycol, diethylene glycol, and polyethylene glycol are consumed in food, or used for personal care and water treatment, or used as synthetic lubricants or fluids for metal working.