Experimental investigation and thin-layer modelling of cassava slice drying

Abstract

This study investigated the effects of drying temperature, slice thickness and slice angle on cassava slice drying and determined suitable thin-layer model with an online weighing fixed bed (Macro-TGA). The experimental results showed that drying temperature and slice thickness were critical factors for cassava slice drying. Based on the experimental data, the activation energy for diffusion was calculated to be 39.37 kJ mol−1, characterizing the drying difficulty of the cassava slice drying. Ten thin-layer drying models, which were semi-theoretical models or empirical, were fitted to the drying data, and the correlation coefficient (R2), Chi-square (χ2), root mean square error and applicability were compared. It was concluded that two-term exponential model described the drying most satisfactorily, with good statistical analysis coefficients and simple functions of model parameters. The model parameters were determined as functions of temperature and slice thickness. Predictions of one case with two-term exponential model were compared with experimental data and the correlation coefficient was 0.99852, indicating good prediction.