Triglyceride (TG)

Triglyceride is a glyceride in which the glycerol is esterified with three fatty acids. It is the main constituent of vegetable oil and animal fats.The chemical formula is RCOO-CH₂CH(-OOCR')CH₂-OOCR", where R, R', and R" are longer alkyl chains. The three fatty acids RCOOH, R'COOH and R"COOH can be all different, all the same, or only two the same.

Triglycerides are formed from a single molecule of glycerol, combined with three fatty acids on each of the OH groups, and make up most of fats digested by humans. Ester bonds form between each fatty acid and the glycerol molecule. This is where the enzyme pancreatic lipase acts, hydrolysing the bond and "releasing" the fatty acid. In triglyceride form, lipids cannot be absorbed by the duodenum. Fatty acids, monoglycerides (one glycerol, one fatty acid) and some diglycerides are absorbed by the duodenum, once the triglycerides have been broken down.