Palmitic acid ( hexadecanoic acid in IUPAC nomenclature) is a
/ref> Its chemical formula is , 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 of palm oil from the fruit of Elaeis guineensis (), 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.
Palmitates are the salts and 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.
Dietary palmitic acid intake is associated with an increased cardiovascular disease risk through raising low-density lipoprotein.
Occurrence and production
Palmitic acid was discovered by
saponification of palm oil, which process remains today the primary industrial route for producing the acid.
(fats) in
palm oil are
hydrolysed by high-temperature water and the resulting mixture is fractionally distilled.
Dietary sources
Palmitic acid is produced by a wide range of plants and organisms, typically at low levels. Among common foods it is present in
milk,
butter,
cheese, and some
, as well as
cocoa butter,
olive oil,
soybean oil, and
sunflower oil, (see table).
contain 44.90% palmitic acid.
The
cetyl alcohol ester of palmitic acid,
cetyl palmitate, occurs in
spermaceti.
Biochemistry
Palmitic acid is the first fatty acid produced during fatty 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 human
Adipose tissue,
and it is a major, but highly variable, lipid component of
Breast milk.
Palmitic acid comprises nearly half of total human brain saturated fatty acids.
Palmitate negatively feeds back on acetyl-CoA carboxylase (ACC), which is responsible for converting acetyl-CoA to malonyl-CoA, which in turn is used to add to the growing Acyl group, thus preventing further palmitate generation.[ Pathway Map 00061] Some proteins are modified by the addition of a palmitoyl group in a process known as palmitoylation. Palmitoylation is important for localisation of many .
Applications
Surfactant
Palmitic acid is used to produce
,
cosmetics, and industrial mold
. These applications use
sodium palmitate, which is commonly obtained by
saponification of palm oil. To this end, palm oil, rendered from palm trees (species
Elaeis guineensis), is treated with
sodium hydroxide (in the form of caustic soda or lye), which causes
hydrolysis of the
ester groups, yielding
glycerol and sodium palmitate.
Foods
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 in organic products.
[US Soil Association standard 50.5.3]
Military
Aluminium salts of palmitic acid and
naphthenic acid were the
used with volatile petrochemicals during World War II to produce
napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
Research
It is well accepted in the medical community that palmitic acid from dietary sources raises low-density lipoprotein (LDL) and total cholesterol.
[Mensink, Ronald P. (2016). "Effects of saturated fatty acids on serum lipids and lipoproteins: a systematic review and regression analysis". World Health Organization. Retrieved 14 March 2023.][Rao, Gundu HR. (2020). Clinical Handbook of Coronary Artery Disease. Jaypee Brothers Medical Publishers. pp. 186-187. ] The World Health Organization have stated there is convincing evidence that palmitic acid increases cardiovascular disease risk.
[
target="_blank" rel="nofollow"> "Diet, Nutrition and the Prevention of Chronic Diseases". World Health Organization. p. 82. Retrieved 16 March 2023.] Palmitic acid intake is associated with an increased cancer risk, including
prostate cancer.
A 2021 review indicated that replacing dietary palmitic acid and other saturated fatty acids with unsaturated fatty acids, such as oleic acid, could reduce several of cardiovascular and metabolic diseases.
See also
-
Retinyl palmitate
-
Ascorbyl palmitate
-
SN2 Palmitate
-
Juniperic acid (16-hydroxypalmitic acid)
External links
