Triglyceride (triacylglycerol)

Article By:

Parks, John S. Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina.

Last reviewed:July 2020

DOI:https://doi.org/10.1036/1097-8542.709700

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• Triglyceride (triacylglycerol), published June 2014:Download PDF Get Adobe Acrobat Reader

A simple fat or lipid consisting of three fatty acyl chains esterified to a glycerol backbone. A triglyceride (triacylglycerol) is a triester formed from glycerol (the simplest trihydric alcohol, with the formula CH₂OHCHOHCH₂OH) and three molecules of fatty acids (see illustration). The fatty acyl chains of triglycerides may be similar or different in carbon chain length and in the number of double bonds. The fatty acyl chains determine the physical properties of triglycerides. For example, triglyceride molecules that contain fatty acyl chains that are polyunsaturated (that is, with two or more double bonds) have a lower melting temperature than triglyceride molecules that have more saturated fatty acyl chains (for example, fatty acid chains with no double bonds). The number of double bonds, that is, the degree of polyunsaturation, of the fatty acyl chains determines whether triglycerides are liquids at room temperature [as is the case with vegetable oils (for example, corn, canola, and safflower oils)] or solids (for example, butter, lard, and beef tallow). See also: Carbon; Chemical bonding; Lipid

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