Power control in microwave drying of green turnip

Abstract

In microwave (MW) drying, the adjustable incident MW power is preferred to improve the product quality and reduce energy consumption. However, the control of incident MW power during the drying process is still a challenging task. By comparing continuous and intermittent microwave drying with gradually reduced microwave power, a control strategy in microwave drying of the green turnip taproot was proposed, based on the experimentally determined dielectric properties and the variation of the electric field intensity with temporal moisture content. The experiments show that such a power control results in higher rehydration ratio of dried green turnip and reduction in energy consumption than these in the continuous and intermittent microwave drying. Moreover, such a power control strategy can maintain the material temperature within the set values with low fluctuations.