DIELECTRIC-PROPERTIES FOR MONITORING THE QUALITY OF HEATED OILS

Dielectric properties (dielectric constant epsilon' and dielectric loss epsilon") were compared to conventional methods of analysis (viscosity, refractive index, iodine value, peroxide value and free fatty acids) for evaluating the frying quality of a blend of cottonseed and sunflower oils. The apparent relaxation time, tau, the activation energy H and the entropy change S for dielectric relaxation of the heated oil samples were calculated. Results indicate that dielectric constant and dielectric loss are useful tools for predicting deterioration occurring during heating of the oil.