Effective Moisture Diffusivity and Activation Energy of Tomato in Thin Layer Dryer during Hot Air Drying

The aim of this paper is to report tomato slice moisture diffusivity data determined and activation energy from experimental drying kinetics. The thin-layer drying experiments were carried out under five air temperatures of 40, 50, 60, 70 and 80oC, two air velocity 1.5, and 2 m/s and three level of relative humidity 20, 40 and 60%. It was observed that drying took place in the falling rate period. Moisture transfer from tomato slice was described by applying the Fick’s diffusion model. The effective diffusivity values changed from 9.9119×10^-10 to 6.4037×10^-9 m^2/s for the range of temperatures considered. An Arrhenius relation with an activation energy value of 33.3299 to 43.2287 kJ/mol and the diffusivity constant value of 1.7695×10^-4 to 3.09156×10^-2 m^2/s were obtained which shows the effect of drying air temperature, air velocity and relative humidity on the diffusivity.