Study on effective moisture diffusivity, activation energy and mathematical modeling of thin layer drying kinetics of bell pepper

Thin-layer drying kinetics of bell pepper was experimentally investigated in a laboratory scale convective dryer. Experiments were performed at air temperatures of 40, 50, 60, 70, and 80 degrees C and constant air velocity of 2 m/s. In order to select a suitable form of the drying curve, 12 different thin layer drying models were fitted to experimental data. The high values of coefficient of determination and the low values of reduced chi-square and root mean square error indicated that the Logarithmic model could satisfactorily illustrate the drying curve of bell pepper. The Logarithmic model had the highest value of R(2) (0.9929), the lowest chi(2) (0.00003497) and RMSE (0.00481743). The Logarithmic model was found to satisfactorily describe the drying behavior of bell pepper. Fick's second law was used to calculate the Effective moisture diffusivity. The moisture diffusion coefficient varied between 1.7 x 10(-9) and 11.9 x 10(-9) m(2)/s for the given temperature range and corresponding activation energy was 44.49 kJ/mol.