Analysis of Neutral Lipids: Triacylglycerols

Abstract

Triacylglycerols (TAGs) are complex molecules pre-sent in all oils and fats. They mainly serve as energy stores, but they are also employed as carriers of fatty acids within aqueous solutions such as blood. TAGs are made up of three fatty acids, attached to a glyc-erol backbone by an ester linkage. The wide variety of fatty acids that may attach to the glycerol back-bone generates the large diversity of TAGs that can be found. The fat stores of both plant and animal organisms are formed by mixtures of TAGs, the fatty acids containing from four to 36 carbon atoms, with up to six double bonds. Each of these fatty acids are combined in triplets to form TAGs that share very similar physicochemical properties, thus making their separation and analysis difficult. The length of the hydrocarbon chains of the fatty acids and the location of the double bonds within the TAG molecule is ordered and determines the spatial configuration, and therefore, the physical properties of the molecule. TAGs that contain a higher proportion of unsaturated fats and fewer carbon atoms are more polarized. Regardless of the saturated fatty acids (SFAs), most of the monounsaturated fatty acids (MUFAs) have the double bond situated between carbons C9 and C10 (9). With respect to the poly-unsaturated fatty acids (PUFAs), the double bond is often located between carbons C12 and C15. These double bonds are not naturally conjugated, but rather a methyl group normally remains between them.