Mathematical modelling of thin-layer drying in peanut fruit

ABSTRACT The aim of this study was to fit mathematical models to the experimental data from the thin-layer drying of peanut fruit subjected to different drying-air temperatures. Peanut fruit from the IAC 505 cultivar were used. The peanut fruit were subjected to drying in a forced ventilation oven at different temperature levels (40, 50, 60 and 70 ºC). Ten mathematical models, traditionally used to represent the kinetics of thin-layer drying, were fit to the experimental data. Based on the results, it can be concluded that among the models adjusted to the experimental data, the Page model was chosen to represent the phenomenon of thin-layer drying in peanut fruit. The effective diffusion coefficient increases with the rise in temperature, and its relation to the drying temperature can be described by the Arrhenius equation. The values for the thermodynamic properties, enthalpy and entropy, were reduced with the increasing temperature of the drying air, while the values for Gibbs free energy increased with the increase in temperature.