关键词: 间歇微波干燥, 热风干燥, 活化能, 有效扩散系数, 颜色

Abstract: The effectiveness of various microwave-convective drying treatments (pulse ratio and air) on the drying characteristics and quality of white radish slices was studied. The moisture ratio, drying rate, effective diffusivity (Deff), and activation energy (Ea) were assessed, and the internal temperature of samples during the drying process and final product color were measured. The Deff increased gradually and then rapidly as moisture content decreased. The Ea of samples increased slightly and then increased rapidly as the moisture content decreased. A logistic model could describe the relationship between Ea and moisture content well. The Ea of samples without air was the highest. Among all the drying treatments, the samples dried with a high pulse ratio (on/off, 5 s/20 s) at a low hot air temperature (30 ℃) exhibited the lowest temperature and the lowest difference between the maximum and minimum temperature of samples and had the most desirable color.

Key words: intermittent microwave drying, air drying, activation energy, effective diffusivity, color