Триглицериды: состав, свойства и применение

Any ester of glycerol having all three hydroxyl groups esterified with fatty acids

A triglyceride (from tri and glyceride; also TG, triacylglycerol, TAG, or triacylglyceride) 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. Many types of triglycerides exist. One specific classification focuses on saturated and unsaturated types. Saturated fats have no C=C groups; unsaturated fats feature one or more C=C groups. Unsaturated fats tend to have a lower melting point than saturated analogues; as a result, they are often liquid at room temperature.

The three fatty acids substituents can be the same, but they are usually different. Many triglycerides are known because many fatty acids are known. The chain lengths of the fatty acid groups vary in naturally occurring triglycerides, Those containing 16, 18, or 20 carbon atoms are defined as long chain triglycerides, while medium chain triglycerides contain shorter fatty acids. Animals synthesize even numbered fatty acids, but bacteria possess the ability to synthesise odd and branched chain fatty acids. As a result, ruminant animal fat contains odd numbered fatty acids, such as 15, due to the action of bacteria in the rumen. Many fatty acids are unsaturated; some are polyunsaturated (e. g., those derived from linoleic acid). A triglyceride containing different fatty acids is known as a mixed triglyceride. These are more common in nature. If the first and third fatty acids on the glycerol differ, then the mixed triglyceride is chiral.

Triglycerides are colorless, although degraded samples can appear yellowish. Stearin, a simple, saturated, symmetrical triglyceride, is a solid near room temperature, but most examples are oils. Their density is near 0. 0.9 g/cm3.

Linseed oil and related oils are important components of useful products used in oil paints and related coatings. Linseed oil is rich in di and tri unsaturated fatty acid components, which tend to harden in the presence of oxygen. This heat producing hardening process is peculiar to these so called drying oils. It is caused by a polymerization process that begins with oxygen molecules attacking the carbon backbone. Triglycerides are also split into their components via transesterification during the manufacture of biodiesel. The resulting fatty acid esters can be used as fuel in diesel engines. The glycerin has many uses, such as in the manufacture of food and in the production of pharmaceuticals.

Staining for fatty acids, triglycerides, lipoproteins, and other lipids is done through the use of lysochromes (fat soluble dyes). These dyes can allow the qualification of a certain fat of interest by staining the material a specific color. Some examples: Sudan IV, Oil Red O, and Sudan Black B.