Accelerated Drying of Alfalfa (Medicago sativa L.) by Microwave Dryer

In this paper, a laboratory microwave oven was used to dry the alfalfa, applying microwave power in the five levels of 180, 360, 540, 720 and 900W. The drying rate curve of alfalfa contained no constant rate period, but showed a falling rate period. Drying processes were completed between 4 and 9 min depending on the microwave power level. The fitting of experimental data with three models (Lewis, Henderson - Pabis and Wang - Singh) showed that drying curves were best described by the Wang - Singh model. Effective moisture diffusivity was estimated using the analytical solution of Fickʹs law. The effective moisture diffusivity was found to be in the range of 2.01x10* 6m2/s to 4.344x10* 6m2/s for alfalfa. In conclusion, showed that higher microwave power cause shorter drying time.