Palmitic acid

Last updated
Palmitic acid [1]
Palmitic acid.svg
Palmitic-acid-3D-balls.png
Kyselina palmitova.jpg
Names
Preferred IUPAC name
Hexadecanoic acid
Other names
Palmitic acid
C16:0 (Lipid numbers)
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.000.284 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C16H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16(17)18/h2-15H2,1H3,(H,17,18) X mark.svgN
    Key: IPCSVZSSVZVIGE-UHFFFAOYSA-N X mark.svgN
  • InChI=1/C16H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16(17)18/h2-15H2,1H3,(H,17,18)
    Key: IPCSVZSSVZVIGE-UHFFFAOYAJ
  • CCCCCCCCCCCCCCCC(=O)O
Properties
C16H32O2
Molar mass 256.430 g/mol
AppearanceWhite crystals
Density 0.852 g/cm3 (25 °C) [2]
0.8527 g/cm3 (62 °C) [3]
Melting point 62.9 °C (145.2 °F; 336.0 K) [4]
Boiling point 351–352 °C (664–666 °F; 624–625 K) [5]
271.5 °C (520.7 °F; 544.6 K), 100 mmHg [2]
215 °C (419 °F; 488 K), 15 mmHg
4.6 mg/L (0 °C)
7.2 mg/L (20 °C)
8.3 mg/L (30 °C)
10 mg/L (45 °C)
12 mg/L (60 °C) [6]
Solubility Soluble in amyl acetate, alcohol, CCl4, [6] C6H6
Very soluble in CHCl3 [3]
Solubility in ethanol 2 g/100 mL (0 °C)
2.8 g/100 mL (10 °C)
9.2 g/100 mL (20 °C)
31.9 g/100 mL (40 °C) [7]
Solubility in methyl acetate 7.81 g/100 g [6]
Solubility in ethyl acetate 10.7 g/100 g [6]
Vapor pressure 0.051 mPa (25 °C) [3]
1.08 kPa (200 °C)
28.06 kPa (300 °C) [8]
Acidity (pKa)4.75 [3]
−198.6·10−6 cm3/mol
1.43 (70 °C) [3]
Viscosity 7.8 cP (70 °C) [3]
Thermochemistry
463.36 J/(mol·K) [8]
Std molar
entropy (S⦵298)
452.37 J/(mol·K) [8]
−892 kJ/mol [8]
10030.6 kJ/mol [3]
Hazards
GHS labelling:
GHS-pictogram-exclam.svg [2]
Warning
H319 [2]
P305+P351+P338 [2]
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
1
0
Flash point 206 °C (403 °F; 479 K) [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Palmitic acid (hexadecanoic acid in IUPAC nomenclature) is a fatty acid with a 16-carbon chain. It is the most common saturated fatty acid found in animals, plants and microorganisms. [9] [10] Its chemical formula is CH3(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 of palm oil from the fruit of Elaeis 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]

Contents

Palmitates are the salts and esters 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]

Occurrence and production

Palmitic acid was discovered by Edmond Frémy (in 1840) in the saponification of palm oil, which process remains today the primary industrial route for producing the acid. [13] Triglycerides (fats) in palm oil are hydrolysed by high-temperature water and the resulting mixture is fractionally distilled. [14]

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 meats, as well as cocoa butter, olive oil, soybean oil, and sunflower oil, (see table). [15] Karukas contain 44.90% palmitic acid. [16] The cetyl ester of palmitic acid, cetyl palmitate, occurs in spermaceti.

Palmitic acid content of common foods
Food % of total calories
Palm oil 45.1%
Beef tallow 26.5%
Butter fat 26.2%
Cocoa butter 25.8%
Lard 24.8%
Cottonseed oil 24.7%
Chicken 23.2%
Corn oil 12.2%
Peanut oil 11.6%
Soybean oil 11%
Coconut oil 8.4%
Palm kernel oil 8%
Rapeseed oil 3.6%
Source: [17]

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 depot fat, [18] and it is a major, but highly variable, lipid component of human breast milk. [19] 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 chain, thus preventing further palmitate generation. [20]

Some proteins are modified by the addition of a palmitoyl group in a process known as palmitoylation. Palmitoylation is important for localisation of many membrane proteins.

Applications

Surfactant

Palmitic acid is used to produce soaps, cosmetics, and industrial mold release agents. 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. [21]

Military

Aluminium salts of palmitic acid and naphthenic acid were the gelling agents used with volatile petrochemicals during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid. [22]

Research

It is well accepted in the medical community that palmitic acid from dietary sources raises low-density lipoprotein (LDL) and total cholesterol. [17] [23] [24] [25] The World Health Organization have stated there is convincing evidence that palmitic acid increases cardiovascular disease risk. [26]

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 biomarkers of cardiovascular and metabolic diseases. [27]

See also

Related Research Articles

<span class="mw-page-title-main">Fat</span> Esters of fatty acid or triglycerides

In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.

Omega−3 fatty acids, also called Omega−3 oils, ω−3 fatty acids or n−3 fatty acids, are polyunsaturated fatty acids (PUFAs) characterized by the presence of a double bond, three atoms away from the terminal methyl group in their chemical structure. They are widely distributed in nature, being important constituents of animal lipid metabolism, and they play an important role in the human diet and in human physiology. The three types of omega−3 fatty acids involved in human physiology are α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA can be found in plants, while DHA and EPA are found in algae and fish. Marine algae and phytoplankton are primary sources of omega−3 fatty acids. DHA and EPA accumulate in fish that eat these algae. Common sources of plant oils containing ALA include walnuts, edible seeds, and flaxseeds as well as hempseed oil, while sources of EPA and DHA include fish and fish oils, and algae oil.

<span class="mw-page-title-main">Triglyceride</span> Any ester of glycerol having all three hydroxyl groups esterified with fatty acids

A triglyceride is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils.

Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health, but cannot synthesize them.

<span class="mw-page-title-main">Coconut oil</span> Edible oil derived from coconut

Coconut oil is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around 25 °C (77 °F), and a clear thin liquid oil in warmer climates. Unrefined varieties have a distinct coconut aroma. Coconut oil is used as a food oil, and in industrial applications for cosmetics and detergent production. The oil is rich in medium-chain fatty acids.

A saturated fat is a type of fat in which the fatty acid chains have all single bonds. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched chain of carbon (C) atoms. Along the chain, some carbon atoms are linked by single bonds (-C-C-) and others are linked by double bonds (-C=C-). A double bond along the carbon chain can react with a pair of hydrogen atoms to change into a single -C-C- bond, with each H atom now bonded to one of the two C atoms. Glyceride fats without any carbon chain double bonds are called saturated because they are "saturated with" hydrogen atoms, having no double bonds available to react with more hydrogen.

An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.

<span class="mw-page-title-main">Stearic acid</span> Eighteen-carbon straight-chain fatty acid

Stearic acid is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a soft waxy solid with the formula CH3(CH2)16CO2H. The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid is a prevalent fatty-acid in nature, found in many animal and vegetable fats, but is usually higher in animal fat than vegetable fat. It has a melting point of 69.4 °C and a pKa of 4.50.

In biochemistry and nutrition, a monounsaturated fat is a fat that contains a monounsaturated fatty acid (MUFA), a subclass of fatty acid characterized by having a double bond in the fatty acid chain with all of the remaining carbon atoms being single-bonded. By contrast, polyunsaturated fatty acids (PUFAs) have more than one double bond.

Lauric acid, systematically dodecanoic acid, is a saturated fatty acid with a 12-carbon atom chain, thus having many properties of medium-chain fatty acids. It is a bright white, powdery solid with a faint odor of bay oil or soap. The salts and esters of lauric acid are known as laurates.

Palm kernel oil is an edible plant oil derived from the kernel of the oil palm tree Elaeis guineensis. It is related to other two edible oils: palm oil, extracted from the fruit pulp of the oil palm, and coconut oil, extracted from the kernel of the coconut.

<span class="mw-page-title-main">Retinyl palmitate</span> Vitamin A chemical compound

Retinyl palmitate, or vitamin A palmitate, is the ester of retinol (vitamin A) and palmitic acid, with formula C36H60O2. It is the most abundant form of vitamin A storage in animals.

<span class="mw-page-title-main">Palmitoleic acid</span> Chemical compound

Palmitoleic acid, or (9Z)-hexadec-9-enoic acid, is an omega-7 monounsaturated fatty acid (16:1n-7) with the formula CH3(CH2)5CH=CH(CH2)7COOH. It is a rare component of fats. It is a common constituent of the glycerides of human adipose tissue. It is present in all tissues but, in general, found in higher concentrations in the liver.

<span class="mw-page-title-main">Medium-chain triglyceride</span> Medium-chain fatty acids

Medium-chain triglycerides (MCTs) are triglycerides with two or three fatty acids having an aliphatic tail of 6–12 carbon atoms, i.e. medium-chain fatty acids (MCFAs). Rich food sources for commercial extraction of MCTs include palm kernel oil and coconut oil.

<span class="mw-page-title-main">Palmitoylation</span>

Palmitoylation is the covalent attachment of fatty acids, such as palmitic acid, to cysteine (S-palmitoylation) and less frequently to serine and threonine (O-palmitoylation) residues of proteins, which are typically membrane proteins. The precise function of palmitoylation depends on the particular protein being considered. Palmitoylation enhances the hydrophobicity of proteins and contributes to their membrane association. Palmitoylation also appears to play a significant role in subcellular trafficking of proteins between membrane compartments, as well as in modulating protein–protein interactions. In contrast to prenylation and myristoylation, palmitoylation is usually reversible (because the bond between palmitic acid and protein is often a thioester bond). The reverse reaction in mammalian cells is catalyzed by acyl-protein thioesterases (APTs) in the cytosol and palmitoyl protein thioesterases in lysosomes. Because palmitoylation is a dynamic, post-translational process, it is believed to be employed by the cell to alter the subcellular localization, protein–protein interactions, or binding capacities of a protein.

Vaccenic acid is a naturally occurring trans fatty acid and an omega-7 fatty acid. It is the predominant kind of trans-fatty acid found in human milk, in the fat of ruminants, and in dairy products such as milk, butter, and yogurt. Trans fat in human milk may depend on trans fat content in food.

Oleochemistry is the study of vegetable oils and animal oils and fats, and oleochemicals derived from these fats and oils. The resulting product can be called oleochemicals (from Latin: oleum "olive oil"). The major product of this industry is soap, approximately 8.9×106 tons of which were produced in 1990. Other major oleochemicals include fatty acids, fatty acid methyl esters, fatty alcohols and fatty amines. Glycerol is a side product of all of these processes. Intermediate chemical substances produced from these basic oleochemical substances include alcohol ethoxylates, alcohol sulfates, alcohol ether sulfates, quaternary ammonium salts, monoacylglycerols (MAG), diacylglycerols (DAG), structured triacylglycerols (TAG), sugar esters, and other oleochemical products.

SN2 Palmitate is a structured triglyceride where palmitic acid is bonded to the middle position (sn-2) of the glycerol backbone. Structured triglycerides are achieved through an enzymatic process using vegetable oils. Current usage of structured triglycerides is mainly for infant formula providing a human milk fat substitute.

<span class="mw-page-title-main">Cooking oil</span> Oil consumed by humans, of vegetable or animal origin

Cooking oil is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.

<span class="mw-page-title-main">Trans fat</span> Type of unsaturated fat

Trans fat, also called trans-unsaturated fatty acids, or trans fatty acids, is a type of unsaturated fat that occurs in foods. Trace concentrations of trans fats occur naturally, but large amounts are found in some processed foods. Since consumption of trans fats is unhealthy, artificial trans fats are highly regulated or banned in many nations. However, they are still widely consumed in developing nations, resulting in hundreds of thousands of deaths each year. The World Health Organization (WHO) had set a goal to make the world free from industrially produced trans fat by the end of 2023.

References

  1. ↑ Merck Index , 12th Edition, 7128.
  2. 1 2 3 4 5 6 Sigma-Aldrich Co., Palmitic acid. Retrieved on 2014-06-02.
  3. 1 2 3 4 5 6 7 CID 985 from PubChem
  4. ↑ Beare-Rogers, J.; Dieffenbacher, A.; Holm, J.V. (2001). "Lexicon of lipid nutrition (IUPAC Technical Report)". Pure and Applied Chemistry. 73 (4): 685–744. doi: 10.1351/pac200173040685 . S2CID   84492006.
  5. ↑ Palmitic acid at Inchem.org
  6. 1 2 3 4 "Palmitic acid".
  7. ↑ Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand. Retrieved 2014-06-02.
  8. 1 2 3 4 n-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)
  9. ↑ Gunstone, F. D., John L. Harwood, and Albert J. Dijkstra. The Lipid Handbook, 3rd ed. Boca Raton: CRC Press, 2007. ISBN   0849396883 | ISBN   978-0849396885
  10. ↑ The most common fatty acid is the monounsaturated oleic acid. See: https://pubchem.ncbi.nlm.nih.gov/compound/965#section=Top
  11. ↑ Gianfranca Carta; Elisabetta Murru; Sebastiano Banni; Claudia Manca (8 November 2017). "Palmitic Acid: Physiological Role, Metabolism and Nutritional Implications". Frontiers in Physiology. 8: 902. doi: 10.3389/FPHYS.2017.00902 . ISSN   1664-042X. PMC   5682332 . PMID   29167646. Wikidata   Q46799280.
  12. ↑ Loften, J.R.; Linn, J.G.; Drackley, J.K.; Jenkins, T.C.; Soderholm, C.G.; Kertz, A.F. (August 2014). "Invited review: Palmitic and stearic acid metabolism in lactating dairy cows". Journal of Dairy Science. 97 (8): 4661–4674. doi: 10.3168/jds.2014-7919 . ISSN   0022-0302. PMID   24913651.
  13. ↑ Frémy, E. (1842). "Memoire sur les produits de la saponification de l'huile de palme". Journal de Pharmacie et de Chimie. XII: 757.
  14. ↑ Anneken, David J.; Both, Sabine; Christoph, Ralf; Fieg, Georg; Steinberner, Udo; Westfechtel, Alfred (2006). "Fatty Acids". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a10_245.pub2. ISBN   978-3527306732.
  15. ↑ "Chemical Characteristics". Olive Oil Source. Retrieved November 11, 2021.[ dead link ]
  16. ↑ Purwanto, Y.; Munawaroh, Esti (2010). "Etnobotani Jenis-Jenis Pandanaceae Sebagai Bahan Pangan di Indonesia" [Ethnobotany Types of Pandanaceae as Foodstuffs in Indonesia](PDF). Berkala Penelitian Hayati (in Indonesian). 5A: 97–108. ISSN   2337-389X. OCLC   981032990 . Retrieved 10 November 2021.
  17. 1 2 Nelson, Gary J. (1991). Health Effects of Dietary Fatty Acids. American Oil Chemists' Society. pp. 84-86. ISBN   978-0935315318
  18. ↑ Kingsbury, K. J.; Paul, S.; Crossley, A.; Morgan, D. M. (1961). "The fatty acid composition of human depot fat". Biochemical Journal . 78 (3): 541–550. doi:10.1042/bj0780541. PMC   1205373 . PMID   13756126.
  19. ↑ Jensen, RG; Hagerty, MM; McMahon, KE (June 1978). "Lipids of human milk and infant formulas: a review". Am. J. Clin. Nutr. 31 (6): 990–1016. doi: 10.1093/ajcn/31.6.990 . PMID   352132.
  20. ↑ "Fatty acid biosynthesis - Reference pathway". KEGG . Pathway Map 00061
  21. ↑ US Soil Association standard 50.5.3
  22. ↑ Mysels, Karol J. (1949). "Napalm. Mixture of Aluminum Disoaps". Industrial & Engineering Chemistry. 41 (7): 1435–1438. doi:10.1021/ie50475a033.
  23. ↑ Mensink RP, Zock PL, Kester AD, Katan MB (2003). "Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials". Am J Clin Nutr. 77 (5): 1146–1155. doi: 10.1093/ajcn/77.5.1146 . PMID   12716665.
  24. ↑ 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.
  25. ↑ Rao, Gundu HR. (2020). Clinical Handbook of Coronary Artery Disease. Jaypee Brothers Medical Publishers. pp. 186-187. ISBN   978-9389188301
  26. ↑ "Diet, Nutrition and the Prevention of Chronic Diseases". World Health Organization. p. 82. Retrieved 16 March 2023.
  27. ↑ Sellem, Laury; Flourakis, Matthieu; Jackson, Kim G; Joris, Peter J; Lumley, James; Lohner, Szimonetta; Mensink, Ronald P; Soedamah-Muthu, Sabita S; Lovegrove, Julie A (2021-11-25). "Impact of Replacement of Individual Dietary SFAs on Circulating Lipids and Other Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Humans". Advances in Nutrition. 13 (4): 1200–1225. doi: 10.1093/advances/nmab143 . ISSN   2161-8313. PMC   9340975 . PMID   34849532.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.