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. Easter bonds from between each fatty acid and the glycerol molecule.
General structure of a triglyceride Chemical formula:
RCOO-CH2 CH(-OOCR)CH2 -OOCR, where R, R’, and R” are longer alkyl chains.
The three fatty acids RCOOH, RCOOH and RCOOH can be all different, all the same, or only two the same. Chain lengths of the fatty acids in naturally occurring triglycerides can be of varying lengths, but 16, 18 and 20 carbons are the most common.
Natural fatty acids found in plants and animals are typically composed only of even numbers of carbon atoms due to the way they are biosynthesized from acetyl CoA. Bacteria, however, possess the ability to synthesis odd – and branched – chain fatty acids. Consequently, ruminant animal fat contains odd numbered fatty acids, such as 15, due to the action of bacteria in the rumen.