MOLECULE

Stearic acid

Stearic acid, also known as stearate or octadecanoic acid, belongs to the class of organic compounds known as long-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 13 and 21 carbon atoms. Stearic acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. It is a waxy solid and is one of the most common saturated fatty acids found in nature (being a close second to palmitic acid). The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid is obtained from fats and oils by the saponification of the triglycerides, like stearin, using hot water. Stearic acid exists in all living organisms, ranging from bacteria to humans. Stearic acid has been detected, but not quantified in, several different foods, such as sweet bay, rose hips, muscadine grapes, pummelo, and garland chrysanthemums. Fats and oils rich in stearic acid are more abundant in animal fat (up to 30%) than in vegetable fat (typically <5%). The important exceptions are the foods cocoa butter and shea butter, where the stearic acid content (as a triglyceride) is 28–45%. In terms of its biosynthesis, stearic acid is produced from carbohydrates via the fatty acid synthesis machinery wherein acetyl-CoA contributes two-carbon building blocks. Stearic acid is mainly used in the production of detergents, soaps, and cosmetics such as shampoos and shaving cream products. Fatty acids are classic components of candle-making. Stearic acid is used along with simple sugar or corn syrup as a hardener in candies. In epidemiologic and clinical studies, stearic acid was found to be associated with lowered LDL cholesterol in comparison with other saturated fatty acids (PMID:19939984). Stearic acid is also a constituent of cannabis plant and cannabis smoke. It is volatilized during the combustion of cannabis (https://doi.org/10.1007/978-1-59259-947-9_2).