ABSTRACT
Around 95 per cent of dietary fats and oils are in the form of triacylglycerol (note that the alternative term triglyceride is still widely used). Most of the storage fat in the body is also in the form of triacylglycerol. Triacylglycerols are composed of three fatty acids linked to the simple three-carbon molecule glycerol. Glycerol is a carbohydrate moiety which is called a tri-alcohol and has one hydroxyl (alcohol) group on each of its three carbons (propane n-1,2,3-triol in formal chemical nomenclature). Each of these alcohol groups in glycerol can form an ester linkage with the carboxyl (acid) group of a fatty acid. The three fatty acids in a triacylglycerol can be the same (simple triacylglycerol) or different (mixed triacylglycerol). A triacylglycerol molecule is represented diagrammatically in Figure 11.1a. Note that the term ‘fat’ is often used to imply a solid substance but oils and solid fats are collectively termed fats in this book.
