关键词: 黄姜片, 热泵干燥, 数学模型, 有效水分扩散系数, 干燥活化能

Abstract: In order to optimize the heat pump drying process of yellow ginger slices and explore the optimal drying parameters, the Box-Behnken orthogonal experimental design was used to determine the optimal process of heat pump drying of yellow ginger slices by taking drying temperature, thickness of yellow ginger slices, and air outlet speed as the three experimental factors, to calculate the moisture ratio of the yellow ginger slices in each group of experiments, and to determine the optimal mathematical model for heat pump drying of yellow ginger slices by using PyCharm software. The results showed that the drying temperature and the thickness of the slices had great influence on the drying rate, while the air outlet speed had little influence on the drying rate. Box-Behnken orthogonal test showed that the optimal drying process was 63 ℃, 2 mm thickness and 2 m/s air discharge speed. Five common mathematical models of thin layer drying were selected, including Lewis, Page, Modified Page, Henderson and Papis, and Tow-term. The determination coefficient, sum of squares of deviation, and root mean square error were compared. The Modified Page was determined to be the optimal model in the drying process. The effective moisture diffusion coefficient of turmeric slices had a positive correlation with drying temperature, thickness of turmeric slices, and air outlet speed, and its value varied in the range of 1.46×10-8~4.68×10-8, and the drying activation energy was 39.71 kJ/mol.

Key words: yellow ginger slices, heat pump drying, mathematical model, effective water diffusion coefficient, dry activation energy