Characterization of used frying oils. Part 2: Comparison of olestra and triglyceride

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Abstract
In this study, the analytical scheme presented in our previous paper [Gardner, D. R., R. A. Sanders, D. E. Henry, D. H. Tallmadge and H. W. Wharton,J. Am. Oil Chem. Soc. 69:499 (1992)] was used to provide a detailed qualitative comparison between a heated olestra and a heated triglyceride that had been used to fry potatoes. The purpose was to determine if unique components are created in olestra when it is exposed to typical frying conditions. Prior to their analysis, the heated and unheated olestra and triglyceride were converted to their corresponding fatty acid methyl esters (FAMEs) by transesterification. The FAMEs obtained were separated by degree of polarity by means of adsorption chromatography and solid‐phase extraction. High‐resolution capillary gas and liquid chromatography were used to profile isolated fractions, and detailed comparisons of these profiles were carried out in an effort to disclose components only present in the heated olestra. Spectroscopic data confirmed that by the methods employed, the only detectable qualitative differences between heated triglyceride and heated olestra were attributable to components also observed in unheated olestra. These species are generated during the manufacture of olestra and are not uniquely created by its use as a frying oil. In those chromatographic fractions containing altered fatty acids, no components were observed to be generated at levels ≥5 ppm upon heating olestra that were not also generated upon heating triglyceride.