Types of Lipids
Triglycerides T riglycerides are the most common type of lipid found in foods and in the body. About 95% of the fats we eat and 95% of the fat stored in the body are in the form of triglycerides. Structure: Triglycerides are built from a glycerol backbone and 3 fatty acids. Glycerol has 3 carbons in its chain. A triglyceride forms when each hydroxyl group on the glycerol backbone bonds with the hydrogen atom from the acid (carboxyl) end of a fatty acid. The bond between a fatty acid and glycerol is called an ester bond. One molecule of water forms each time an ester bond forms (this is called esterification), Thus, when a diglyceride (2 fatty acids attached to a glycerol backbone) forms, 2 molecules of water form. Similarly, forming a triglyceride will generate 3 water molecules. Esterification is a condensation reaction. A molecule of water is used when a fatty acid breaks away from a glycerol backbone (this hydrolysis reaction can be thought of as "de-esterification"). R...