Methods for surveying the quality of frying fats and oils

Palm, peanut and soy bean oils were exposed to high temperature with and wi thout food products, and the amounts of polar substances, a measure of heat abuse, were determined using the time consuming standard procedure (prepar ative column chromatography) and much faster alternative methods. High perf ormance liquid chromatography allows complete separation and quantification of the non-polar and the polar fractions. Low-resolution nuclear magnetic resonance and near infra-red spectroscopy can also be applied. A commercial food oil sensor based on dielectric measurements is also useful to investi gate heat abuse of frying fats and oils. The type of frying food influenced the rate of sensory deterioration in the oils.