Fat Characterization

The importance of fat characterization is evident in many facets of the food industry, including ingredient technology, product development, quality assurance, product shelf life, and regulatory aspects. Also, lipids are closely associated with health, requiring analysis for specific lipids of interest. The methods described in this chapter are used to characterize bulk oils and fats and the lipids in foods. Methods described for bulk oils and fats are used to determine physical characteristics such as melting point, smoke point, color, and consistency. Methods for chemical characteristics include degree of unsaturation, free fatty acids, and amount of polar compounds. The tests for conjugated dienes, peroxide value, and volatile organic compounds can be used to measure the status of a lipid with regard to oxidation, while accelerated shelf-life tests and oil stability index can be used to determine the stability of a lipid to oxidation and the effectiveness of antioxidants. Lipid fractions, including fatty acids, triacylglycerols, phospholipids, and cholesterol, are commonly analyzed by chromatographic techniques such as gas chromatography and thin layer chromatography.