Intermittent Microwave Drying Characteristics and Quality Changes of Xilin Fire Ginger Slices

In order to improve the drying efficiency, microwave intermittent drying characteristics of Xilin fire ginger slices were studied and drying kinetics model was established. Using microwave power density, intermittent time, laying density and slice thickness as the factors, the moisture changes in the microwave intermittent drying process of Xilin fire ginger slices under various conditions were measured in real time. By fitting four common drying models, the suitable model for microwave intermittent drying of Xilin fire ginger slices was optimized and its parameters were solved. A model for real time microwave intermittent drying of Xilin fire ginger slices was obtained. The results showed that there were three stages in the microwave intermittent drying process: Acceleration, constant speed and deceleration. The higher the microwave power density, the shorter the batch time, the smaller the laying density and the smaller the thickness, the faster the drying rate, the shorter the drying time required. The optimum microwave power density was 0.9 W/g, the intermittent drying time was 1.0 min, the laying density was 0.6 g/cm², and the thickness of slices was 6 mm. The Page model was the most suitable for microwave intermittent drying (R²=0.977), and the effective water diffusion coefficient was (0.9727~7.7815)×10^-9 m²/s. The drying kinetics model established can objectively and effectively reflect the microwave intermittent drying process of Xilin fire ginger slices, and can provide theoretical reference for microwave drying process of Xilin fire ginger slices.