Influences of Heating Methods of Fryer on the Deterioration of Frying Oil

Abstract

The influence of the heating method on the deterioration of frying oil was examined using three commercial fryers with different methods of heating : the electromagnetic heating system (M), electroric heating system (E), and a heating system with gas burner (G).
Soybean oil was heated at 180°C in the three fryers for 49 h (every day 7 h). The degree of oil deterioration was determined and expressed in terms of viscosity, carbonyl and acid content, and optical density. The rate of deterioration was found to increase in the order of M, E and G. The temperature of the surface of heating tube would thus appear to influence the rate of deterioration.
In the case of a small thermal load, the rate of oil deterioration was essentially the same for all three heating methods.