EFFECT OF METAL SHIELDING ON MICROWAVE-HEATING UNIFORMITY OF A CYLINDRICAL FOOD MODEL

Cylindrical model samples containing 3% agar gel were shielded with metal bands during microwave heating. The metal bands were arranged in various patterns, with different spacing and orientation. The focus of this work was to study how these patterns could affect the heating uniformity and power absorption in the samples. The heating rates of the samples during microwaving were measured with fiberoptic temperature sensors. A two-factor central composite rotatable design and the corresponding response surface methodology were used to analyze the data. It was found that orientation was an important design parameter, and it was possible to design patterns that could greatly increase the heating uniformity without greatly reducing the power absorption.