![Monoacylglyceryl2](https://upload.wikimedia.org/wikipedia/commons/b/bd/Monoacylglyceryl2.jpg)
Monoglycerides (also: acylglycerols or monoacylglycerols) are a class of
glyceride
Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids, and are generally very hydrophobic.
Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids ...
s which are composed of a molecule of
glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
linked to a
fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...
via an
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...
bond. As glycerol contains both primary and secondary alcohol groups two different types of monoglycerides may be formed; 1-monoacylglycerols where the fatty acid is attached to a primary alcohol, or a 2-monoacylglycerols where the fatty acid is attached to the secondary alcohol.
Synthesis
Monoglycerides are produced both biologically and industrially. They are naturally present at very low levels (0.1-0.2%) in some
seed oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fa ...
s such as
olive oil,
rapeseed oil and
cottonseed oil
Cottonseed oil is cooking oil from the seeds of cotton plants of various species, mainly '' Gossypium hirsutum'' and ''Gossypium herbaceum'', that are grown for cotton fiber, animal feed, and oil.
Cotton seed has a similar structure to other oi ...
. They are biosynthesized by the enzymatic
hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolys ...
of
triglyceride
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''wikt:tri-#Prefix, tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other ...
s by
lipoprotein lipase
Lipoprotein lipase (LPL) (EC 3.1.1.34, systematic name triacylglycerol acylhydrolase (lipoprotein-dependent)) is a member of the lipase gene family, which includes pancreatic lipase, hepatic lipase, and endothelial lipase. It is a water-solubl ...
and the enzymatic hydrolysis of
diglyceride
A diglyceride, or diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. DAGs can act as su ...
s by
diacylglycerol lipase
Diacylglycerol lipase, also known as DAG lipase, DAGL or DGL, is a key enzyme in the biosynthesis of the endocannabinoid 2-arachidonoylglycerol. It catalyzes the hydrolysis of diacylglycerol, releasing a free fatty acid
In chemistry, particu ...
; or as an intermediate in the
alkanoylation of glycerol to form
fat
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.
The term often refers specifically to triglycerides (triple est ...
s. Several monoglycerides are pharmacologically active (e.g.
2-oleoylglycerol
2-Oleoylglycerol (2OG) is a monoacylglycerol that is found in biologic tissues. Its synthesis is derived from diacylglycerol precursors. It is metabolized to oleic acid and glycerol primarily by the enzyme monoacylglycerol lipase (MAGL). In 2011, ...
,
2-arachidonoylglycerol
2-Arachidonoylglycerol (2-AG) is an endocannabinoid, an endogenous agonist of the CB1 receptor and the primary endogenous ligand for the CB2 receptor. It is an ester formed from the omega-6 fatty acid arachidonic acid and glycerol. It is present ...
).
Industrial production is primarily achieved by a
glycerolysis
In organic chemistry glycerolysis refers to any process in which chemical bonds are broken via a reaction with glycerol. The term refers almost exclusively to the transesterification reaction of glycerol with triglycerides (fats/oils) to form mi ...
reaction between
triglycerides
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...
and glycerol.
The commercial raw materials for the production of monoacylglycerols may be either
vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...
s or
animal fats.
Uses
Monoglycerides are primarily used as
surfactants, usually in the form of
emulsifiers
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although ...
. Together with
diglycerides
A diglyceride, or diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. DAGs can act as s ...
, monoglycerides are commonly
added to commercial food products in small quantities as "E471" (s.a.
Mono- and diglycerides of fatty acids
Mono- and diglycerides of fatty acids ( E471) refers to a naturally occurring class of food additive composed of diglycerides and monoglycerides which is used as an emulsifier. It is also used as a fruit coating agent. This mixture is also so ...
), which helps to prevent mixtures of oils and water from separating. The values given in the nutritional labels for total fat, saturated fat, and ''trans'' fat do not include those present in mono- and diglycerides as fats are defined as being
triglycerides
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...
. They are also often found in bakery products, beverages,
ice cream
Ice cream is a sweetened frozen food typically eaten as a snack or dessert. It may be made from milk or cream and is flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit such as ...
,
chewing gum
Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its t ...
,
shortening
Shortening is any fat that is a solid at room temperature and used to make crumbly pastry and other food products. Although butter is solid at room temperature and is frequently used in making pastry, the term ''shortening'' seldom refers to b ...
,
whipped topping
Whipped cream is liquid heavy cream that is whipped by a whisk or mixer until it is light and fluffy and holds its shape, or by the expansion of dissolved gas, forming a firm colloid. It is often sweetened, typically with white sugar, and ...
s,
margarine, spreads and peanut butter, and
confection
Confectionery is the art of making confections, which are food items that are rich in sugar and carbohydrates. Exact definitions are difficult. In general, however, confectionery is divided into two broad and somewhat overlapping categorie ...
s.
In bakery products, monoglycerides are useful in improving loaf volume and texture, and as
antistaling agents.
Monoglycerides are used to enhance the physical stability towards creaming in milk beverages.
Examples
Glyceryl_laurate.png, Monolaurin
Monolaurin (abbreviated GML; also called glycerol monolaurate, glyceryl laurate, and 1-lauroyl-glycerol) is a monoglyceride. It is the mono-ester formed from glycerol and lauric acid. Its chemical formula is C15H30O4.
Uses
Monolaurin is most comm ...
, commonly used in cosmetics and as a food additive
GlycMonoStear-PlainSVG.svg, Glycerol monostearate
Glycerol monostearate, commonly known as GMS, is a monoglyceride commonly used as an emulsifier in foods. It takes the form of a white, odorless, and sweet-tasting flaky powder that is hygroscopic. Chemically it is the glycerol ester of stearic ...
, used in foods as a thickening, emulsifying, and preservative agent
File:1,3-Dihydroxy-2-propanyl_2-hydroxyoctadecanoate.svg, Glyceryl hydroxystearate
Glyceryl hydroxystearate, also known as glyceryl monohydroxystearate (GMHS), is an organic chemical compound with the molecular formula C21 H42 O5. It is a whitish- or pale yellow-colored powder found in a variety of cosmetics and skin-care produ ...
, found in a variety of cosmetic and skin care products.
See also
*
Diglyceride
A diglyceride, or diacylglycerol (DAG), is a glyceride consisting of two fatty acid chains covalently bonded to a glycerol molecule through ester linkages. Two possible forms exist, 1,2-diacylglycerols and 1,3-diacylglycerols. DAGs can act as su ...
*
Dietary sources of fatty acids, their digestion, absorption, transport in the blood and storage
*
Lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids includ ...
*
Triglyceride
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''wikt:tri-#Prefix, tri-'' and ''glyceride'').
Triglycerides are the main constituents of body fat in humans and other ...
References
{{Glycerides
Fatty acid esters
Lipids
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