Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/4/2005
Publication Date: 4/4/2005
Citation: Moreau, R.A. Extraction and analysis of food lipids. Book Chapter. S. Otles (ed), in Methods of Analysis of Food Components and Additives, CRC Press/Taylor and Francis, Boca Raton, pp.97-110 2005.
Technical Abstract: Lipids are often defined as a group of biomolecules that are insoluble in water and soluble in organic solvents such as hexane, diethyl ether or chloroform. W.W. Christie, an international authority on lipids, defines them as follows, "Lipids are fatty acids and their derivatives, and substances related biosynthetically or functionally to these compounds". Because sterols, tocopherols, and carotenoids are common components of lipid extracts often encountered by this author, methods for the analysis of the latter two will be described in this chapter (carotenoid analysis is covered separately in chapter X). Triacylglycerols (Fig. 1a) are the main storage lipid (storing energy and carbon skeletons) in plants and animals. Triacylglycerols include fats (which are solid at 20° C) or oils (which are liquid at 20°C). In general, most fats are found in animal tissues and most oils are found in plant tissues. Since, fats and oils comprise about 40% of the dietary calories in Western Europe and North America, an understanding of their composition is essential to the field of nutrition. "Crude fat" is a compositional term that includes all of the nonpolar lipids that are extractable with diethyl ether (primarily triacylglycerol but also other nonpolar lipids such as waxes, sterols, free fatty acids, and Vitamin E).