Effect of Slice Thickness on Drying Kinetics of Papaya using Food Dehydrator

In this study, the influence of drying air temperature and slice thickness on drying kinetics has been reported. Papaya was sliced into the different thickness of 3, 5 and 7 mm and drying experiments were performed in the food dehydrator (Ezidri Ultra Fd1000, Hydra flow Industries Limited, Newzealand) at temperatures of 45, 55 and 65°C. The experimental moisture loss data were fitted to the seven thin layer drying models. Three statistical parameters Coefficient of determination (R²), reduced-χ² and root mean square error (RMSE) was used to test the mathematical models. All the models gave the best fitting results, but the Page Model shows lower RMSE (0.006), reduced-χ² (0.314x10⁻⁴) and highest R² (1.000) value. The effective diffusivity of slices varied from 7.47751×10⁻⁰⁹ to 5.71×10⁻⁰⁸, effective diffusivity increased with increasing temperature and slice thickness. The activation energy of slices varied from 17.323 kJ/mol to 35.100 kJ/mol it is also increased with increasing thickness.