Palmitic acid (hexadecanoic acid inIUPAC nomenclature) is afatty acid with a 16-carbon chain. It is the most commonsaturated fatty acid found in animals, plants and microorganisms.[9][10] Itschemical formula isCH3(CH2)14COOH, and its C:D ratio (the total number of carbon atoms to the number of carbon-carbon double bonds) is 16:0. It is a major component ofpalm oil from the fruit ofElaeis guineensis (oil palms), making up to 44% of total fats. Meats, cheeses, butter, and other dairy products also contain palmitic acid, amounting to 50–60% of total fats.[11]
Palmitates are thesalts andesters of palmitic acid. The palmitate anion is the observed form of palmitic acid at physiologic pH (7.4). Major sources of C16:0 are palm oil, palm kernel oil, coconut oil, and milk fat.[12]
Dietary palmitic acid intake is associated with an increased cardiovascular disease risk through raisinglow-density lipoprotein.[13]
Palmitic acid is the first fatty acid produced duringfatty acid synthesis and is the precursor to longer fatty acids. As a consequence, palmitic acid is a major body component of animals. In humans, one analysis found it to make up 21–30% (molar) of humandepot fat,[19] and it is a major, but highly variable, lipid component ofhuman breast milk.[20] Palmitic acid comprises nearly half of total human brain saturated fatty acids.[21]
Palmitate negatively feeds back onacetyl-CoA carboxylase (ACC), which is responsible for convertingacetyl-CoA tomalonyl-CoA, which in turn is used to add to the growingacyl chain, thus preventing further palmitate generation.[22] Some proteins are modified by the addition of a palmitoyl group in a process known aspalmitoylation. Palmitoylation is important for localisation of manymembrane proteins.
Palmitic acid is used to producesoaps,cosmetics, and industrial moldrelease agents. These applications usesodium palmitate, which is commonly obtained bysaponification of palm oil. To this end, palm oil, rendered from palm trees (speciesElaeis guineensis), is treated withsodium hydroxide (in the form of caustic soda or lye), which causeshydrolysis of theester groups, yieldingglycerol and sodium palmitate.
Because it is inexpensive and adds texture and "mouthfeel" to processed foods (convenience food), palmitic acid and its sodium salt find wide use in foodstuffs. Sodium palmitate is permitted as a natural additive inorganic products.[23]
Aluminiumsalts of palmitic acid andnaphthenic acid were thegelling agents used with volatile petrochemicals duringWorld War II to producenapalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.[24]
^abcdn-Hexadecanoic acid in Linstrom, Peter J.; Mallard, William G. (eds.);NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-05-11)
