Robert Alan Sanders

Isolation and characterization of polymers in heated Olestra and an Olestra/triglyceride blend.

High molecular weight components in thermally oxidized olestra (formerly called sucrose polyesters) and a mixture of olestra and soybean oil were characterized. The high molecular weight components of these oils were separated by preparative size exclusion chromatography and analyzed intact by mass spectrometry, infrared, and nuclear magnetic resonance spectroscopy. The materials isolated from the heated olestra were identified as olestra polymers. Materials isolated from the heated mixed oil (olestra and soybean oil) were identified as polymers of olestra and copolymers of olestra and triglycerides. Polymer linkages identified were identical to those resulting from thermal oxidation of natural vegetable oils of similar fatty acid composition.

Characterization of used frying oils. Part 1: Isolation and identification of compound classes

In this study, an analytical scheme is presented for detailed qualitative comparisons between heated and unheated oils. This scheme is less subject to loss or alteration of sample components when compared with methods that characterize the distillable non-urea adducting portion of heated oils. In this work, oils were first converted to their corresponding fatty acid methyl esters (FAMEs) by transesterification. These FAMEs were then 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. Mass spectrometric and infrared analyses of major chromatographic features were used to identify the presence of aldehydes, epoxides, ketones, alcohols, phytosterols and dimer methyl esters down to 5 ppm in the original sample.

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

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.

Desorption mass spectrometry of olestra

Field desorption (FD), fast atom bombardment (FAB) and plasma desorption (PD) mass spectrometry have been used for the characterization of olestra, a mixture of octa-, hepta- and hexaesters of sucrose formed by reaction of sucrose with long-chain fatty acids (C12–C18). Most previous applications of desorption ionization mass spectrometry have involved polar compounds; however, the relatively low-polarity olestra is also amenable to these techniques with proper sample preparation. Field desorption provides molecular weight information, but the transience of the signals limits the usefulness for observing fragmentation and measuring ester distributions. In addition, FD may not be sensitive enough to allow characterization of fractions isolated from analytical high-performance liquid chromatography (HPLC) columns. Fast atom bombardment produces longer-lasting signals, which permit characterization of components over a wide mass range. However, signal-to-noise fluctuates substantially, depending on analyte solubility in the matrix, making the characterization of partial esters collected from HPLC uncertain and difficult. Plasma desorption mass spectrometry is the easiest and most sensitive technique for olestra characterization but provides the lowest mass resolution. Because it requires no more than a few µg of material, it is effective for the characterization of HPLC fractions. Furthermore, it is the only method, of the three investigated, that allows detection of intact dimeric species having molecular masses in the 3,000 to 5,000 dalton range.