Modelling of thin-layer drying characteristic of unripe Cardaba banana (Musa ABB) slices

In order to determine the behavior of Cardaba banana during drying, the thin layer drying kinetics were investigated using sun and hot air-drying at the temperature of 50, 60 and 70°C. The drying rate of the convective hot air oven was kept constant at 1.2 m2/s. The drying curves of the Cardaba banana slices contained no constant rate of drying but took place in the falling rate period. Twelve thin-layer drying model were used to fit the drying data and compared according to their coefficients of determination (R2), root mean square error (RMSE) and reduced χ2 to estimate drying curves. Among the thin-layer models, Wang and Singh model with R2 of 0.9953, RMSE of 0.0223 and χ2 of 4.94 × 10−4 was found to best explain the drying behavior of the Cardaba banana slices. Effective moisture diffusivity of Cardaba banana slices increased from 1.46 × 10−8 to 4.25 × 10−8 m2/s, resulting to activation energy of 38.46 kJ/mol. The results obtained proved that Wang model is an efficient thin-layer model that could be used in dryer designing of and processing of Cardaba banana.