EVALUATION OF A SUITABLE THIN LAYER MODEL FOR DRYING OF PRETREATED COCOYAM SLICES USING A CONVECTIVE HOT AIR DRYER

Abstract

This work evaluated the thin layer drying kinetics of pretreated cocoyam slices (Xanthosoma sagittifolium) in a convective hot air dryer. Seven thin layer theoretical and empirical models widely used in describing the drying behaviour of agricultural products were fitted to the experimental data in order to select the appropriate model for predicting the drying kinetics of cocoyam (Xanthosoma sagittifolium). The Page model showed the best fit under certain drying conditions based on the coefficient of determination (R 2 ) and sum of squares error (SSE). Comparison was made between the experimental and model predicted moisture ratio by non-linear regression analysis. Furthermore, the effect of drying temperature and pretreatment on the best model constants was evaluated. Consequently, the page model showed an excellent fit with the experimental data (R 2 > 0.99 and SSE < 0.0010) for the drying temperatures of 50, 60 and 70 °C at different sample pretreatments; untreated (raw), water soaked and brine soaked respectively. Thus, page model can adequately predict the drying kinetics of cocoyam under pretreatment conditions.