ABSTRACT
The thin‐layer drying behavior of water dropwort in a laboratory scale vacuum dryer was examined. Two pretreatments (blanching and 1% KMS dipping) were applied to the water dropwort, which were dried in the ranges of 50–70C of drying air temperature. The drying air temperature and pretreatment had significant effects on the moisture content of the water dropwort samples. In all the drying temperature selected, the blanched samples had shorter drying time than the control and 1% KMS treated samples. The drying rate decreases continuously with decreasing moisture content or increasing drying time. The models were compared based on the coefficient of determination, reduced chi‐square and root mean square error between the observed and predicted moisture ratios. The Page model has shown a better fit to the experimental drying data as compared to other models. The color characteristics of dried water dropwort were also significantly influenced by the pretreatments.
PRACTICAL APPLICATIONS
The information on the drying characteristics of water dropwort as influenced by pretreatments may provide a practical method for the preservation of water dropwort and improvement on the quality of dried products. The experimental data are necessary to design, optimize, and control the drying process in the production of dehydrated water dropwort products.