Umudike Journal of Engineering and Technology

The drying kinetics of plantain slices was studied using the thin layer drying characteristics of plantain slices in a mixed mode convectional solar dryer. The diffusivity and drying models were obtained to describe the drying curve. The dryer used for the experiment had an average drying chamber temperature ranging from 34 - 50^oC, while eight commonly used thinlayer drying models were used for drying curve modeling.  The models performance was evaluated by comparing the coefficient of determination (R²) and Root Mean Square Error (RMSE). The drying curve showed a reduction of moisture content with increased drying time of plantain slices in the solar dryer. It was observed that the drying rate curve followed slightly the average daily temperature variation in the study. The variation of moisture ratio (MR) was found to exponentially decrease with increased drying time. The Midilli model showed the best fit to the experimental drying data as compared to other models tested in the R² and RMSE values obtained. Midilli model had the lowest values of R² and RMSE. The diffusion mechanism could be used to describe the drying of plantain slices which was found to be in the falling rate period. The diffusion coefficient (D_eff) obtained for plantain slices was 1.46x 10^-9 m²s^-1 was within the established standard for food products.