Improvement of temperature uniformity in microwave-reheated rice by optimizing heat/hold cycle

A mathematical model using a finite difference method was established to predict the temperature distribution of a microwave-heated food tray. The model was linked with an optimization algorithm to minimize temperature non-uniformity in the microwave-reheating of a cooked rice package. The mathematical model developed was validated by comparing the predicted and measured temperatures, and was used to obtain the optimum heat/hold cycle. Temperature non-uniformity was predicted to increase initially with time and then decrease after the surface corner temperature reached around 100 °C. Minimized temperature non-uniformity was thus attained with the longest heating time, satisfying the highest allowable average temperature under the appropriate number of heat/hold cycles. The control strategy may serve as a useful concept in food service, to improve the heating uniformity of microwaveable dishes.