- Chemical formula and structure
- Chemical properties
- Foods that contain it
- Palm oil
- Applications
- References
The palmitic acid, or n- hexadecanoic acid in IUPAC nomenclature, is a linear long chain saturated fatty acid found mainly in palm oil (Elaeis guineensis). It is usually present in almost all animal or vegetable fats and is also obtained by chemical synthesis.
Palmitic acid is one of the main fatty acids in cow's milk, which is why it is in cheeses, butter, and dairy products. It is also part of the lipids of human breast milk. It is a main component of the body of animals, so it is contained in meat.
In humans it constitutes between 21 and 30% molar of the fat. It is the first fatty acid produced during lipogenesis (fatty acid synthesis) and from this, longer fatty acids can be produced.
Palmitate is the salt of palmitic acid and cetyl or palmityl alcohol is another chemical derivative; both are used in the cosmetic industry.
Chemical formula and structure
It contains 16 carbon atoms and no unsaturation, so it is represented as 16: 0. Its chemical formula is CH 3 (CH 2) 14 COOH. It can also be indicated as C 16 H 32 O 2.
Saponification is the chemical reaction that occurs when a fatty acid reacts with an alkali. The product of this reaction is glycerol, which is an alcohol and the salt of fatty acid.
Palmitic acid is saponified with sodium hydroxide (caustic soda or lye), to form sodium palmitate, a salt. The chemical formula for sodium palmitate is C 16 H 31 NaO 2.
Cetyl or palmityl alcohol is also derived from palmitic acid. It is a fatty alcohol of the formula CH 3 (CH 2) 15 OH. Vitamin A Palmitate is an antioxidant. Chemically it is the retinol ester (vitamin A) and palmitic acid, with the formula C 36 H 60 O 2.
Chemical properties
Palmitic acid occurs as white, solid, odorless crystals at room temperature. Leaves a grease stain on the paper that does not disappear.
It can only be distilled under vacuum or with superheated steam. It is insoluble in water and soluble in amyl acetate, alcohol, ether, carbon tetrachloride (CCl 4), benzene (C 6 H 6) and very soluble in chloroform (CHCl 3). When heated, it ignites.
Palmitic and stearic acids are almost always found together and both are obtained in a similar way. After being solubilized in boiling alcohol, palmitic acid crystallizes out on cooling to 62.6 ˚C.
The pure acid crystallizes in small crystals, in the form of greasy luster flakes and has a molecular weight of 256.4 g / mol. At 25 ° C its density is 0.852 g / cm 3; its boiling point is 351–352 ° C.
Foods that contain it
Because it is inexpensive and adds texture and contributes to the palatability ("mouthfeel") of processed foods, palmitic acid and its sodium salt are widely used in foods.
Vitamin A Palmitate is added to low-fat or fat-free milk to replace the content of this vitamin that is lost from skimming the milk.
Fat rich in palmitic and stearic acid are cocoa, shea (Vitellaria paradox) and Borneo or illipe (Shorea stenoptera) butter.
Among the oils rich in palmitic acid are that of cotton, which has 22%; and those made from the germ of cereals, such as corn. This contains 13.4% palmitic acid.
Pork butter has 25.4% palmitic acid, beef tallow has 26.5%, goose butter has 21%, butter has 20.6% and cocoa butter has 25%.
Olive oil contains 11.5% and other vegetable oils (soybean, rapeseed, sunflower, sesame, peanut) have palmitic acid content of less than 10%.
Palm oil
The main sources of palmitic acid are palm oil and the by-products of its refining. Crude palm oil is semi-solid at room temperature. It is obtained from the mesocarp of the oil palm fruit, either by pressure or by extraction with solvents.
Its color is yellowish red due to the presence of carotenoid and xanthophyll pigments. That is, it has a high content of provitamin A, as well as vitamin E (tocopherols).
It is characterized by having a practically 1: 1 ratio of palmitic acid and oleic acid (palmitic acid represents 44% and oleic 39%). This composition makes it show high stability against oxidation.
Its consistency means that it does not require hydrogenation, so it is practically free of trans fats. Palm olein, which is the room temperature liquid fraction of palm oil, has 40% palmitic acid.
It is used as edible liquid oil both in pure form and mixed with other liquid oils. It is a very stable oil at high temperatures.
Palm stearin contains 52% palmitic acid, corresponding to the solid fraction at room temperature of palm oil.
The ingestion of palmitic acid contributes to the increase in the consumption of saturated fats and, therefore, to the possible increase in the risk of cardiovascular diseases.
Applications
- Palm stearin is used for the formulation of margarines, solid fats for bakeries, shortenings and in the manufacture of soaps.
- Palm olein is used in industrial frying, and preparation of frozen and dehydrated dishes. Likewise, the mixture of palm olein with other oils and fats is used as a milk substitute and in the formulation of baby food.
- Sodium palmitate is one of the salts that is used to make the base of soaps and some cosmetics. It has surfactant and emulsifying properties, and is also allowed as a natural additive in organic products.
- Cetyl alcohol or palmityl alcohol is produced by chemical reduction of palmitic acid, obtained from palm oil. Cetyl alcohol is used in the cosmetic industry in the manufacture of shampoos, or as an emulsifier in the manufacture of skin creams and lotions.
- It is also used as a lubricant for nuts and bolts, and is the active ingredient in some "liquid pool covers" (forming a surface layer to reduce evaporation and retain heat).
- Palmitic acid and its sodium salt are generally accepted as safe for use in cosmetics. However, as it often contains salts and traces of oleic acid and lauric acids, these can be irritating to some people.
- Aluminum salts of palmitic acid and naphthenic acid were the raw materials used during World War II for the production of napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid.
References
- Astiasarán Anchía, I., Martínez Hernández, A. (2015). Foods. Madrid: McGraw-Hill.
- Cetyl alcohol (2018). Retrieved on April 14, 2018, in Wikipedia.com
- Dubois S. (2017). Palmitic acid health benefits. Retrieved on April 15, 2018 at livestrong.com
- Foods High in Palmitic acid (sf). Retrieved on April 13, 2018 at wholefoodcatalog.info
- Gunstone, F. (1987). Palm oil. Chichester etc: Wiley.
- Norris, F., Gunstone, F. (1983). Lipids in foods. Oxford: Pergamon Press
- Palmitic acid (2018). Retrieved on April 14, 2018, in Wikipedia.com Retinyl palmitate (2018). Retrieved on April 14, 2018, in Wikipedia.com
- Thompson C. (2017). What Is Vitamin A Palmitate? Retrieved on April 15, 2018 at livestrong.com
- Tremblay S. (2017). Sources of Palmitic Acid. Retrieved on April 15, 2018 at livestrong.com