Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: April 25, 2000
Publication Date: N/A
Technical Abstract: Degradation products of various oils used for frying French fries, potato chips, or tortilla chips were evaluated. The investigated oils include sunflower, cottonseed, soybean, and blended. Polar fractions isolated from the frying oils were analyzed for nonvolatile components or decomposition products by high-performance size exclusion chromatrography (HPSEC) with viscometric (VIS)/refractometric (RI) detection. The polymeric products were separated on three polystyrene/divinylbenzene columns of variable porosity with tetrahydrofuran as the mobile phase eluent. Analyte molecular weights (MW) and concentrations were simultaneously determined by monitoring the column effluents in the dual VIS/RI detection mode. Computation of component MWs were performed with a universal calibration technique based on MW/viscosity data for polymer standards. HPSEC of oils derived from different oilseed lines yielded decomposition products apparently derived from triglycerides. MW and composition data for corresponding HPSEC peaks varied depending on the oil type and frying conditions. Elevated levels of high MW components were correlated with the extent of frying oil degradation to serve as potential markers for frying oil stability. Molecular-weight/concentration distribution profiles of various oils, as function of frying times, were delineated. The distribution patterns of degradation products were affected by frying conditions and oil varieties and aided in fingerprint characterization of specific oils. The products comprised mixtures of undefined species inexplicable in terms of a simple polymerization rationale.