The aims of this study were to determine the drying time and the shape of the drying curves of leaves of wolf apple (Solanum lycocarpum A. St.-Hil.) dried at temperatures of 40, 50 and 60ºC in a thin layer fixed-bed dryer at air velocity of 0.81 m s-1, and to estimate the effective diffusion coefficient and activation energy. Eight mathematical models were fit to the experimental data. The magnitude of the coefficient of determination (R²), the mean relative error (P) and the estimated standard error (SE) were used to verify the fitting degree of the models. It was concluded that: a) The drying time decreased with increasing temperatures; b) the drying models of Logarithm and of Midilli et al. best fit to the experimental data; c) The values of the diffusion coefficient increased with the rising temperature of the drying air; d) The value of activation energy for the leaf of Solanum lycocarpum A. St.-Hil. was 44.60 kJ mol-1.
medicinal plants; dehydration; effective diffusivity
