Evaluation of microwave drying characteristics of Ficus deltoidea leaves by using thin layer drying models

Thin layer drying of Ficus deltoidea leaves by microwave dryer was conducted at five different microwave power densities, 40, 35, 30, 22.5, and 15 W g(-1). The results showed that the drying of the leaves occurred only in the falling rate- drying period. The experimental moisture ratios versus drying time were fitted to five selected widely used thin-layer mathematical models namely Lewis, Page, Modified Page, Midili et al. and Henderson & Pabis. The goodness of fit of the five models was compared in terms of the coefficients of determination (R-2), root mean square errors (RMSE), and reduced chi-squares (chi(2)). Among the five selected models, Midili et al. model best fitted to the experimental moisture ratio data with R-2, RMSE and chi(2) ranged from 0.9982 to 0.9999, 0.0147 to 0.0021 and 2.3137x10(-4) to 1.467x10(-5), respectively. Thus Midili et al. model can be used to describe the drying process of Ficus deltoidea leaves within the five microwave power density range.