Drying kinetics and thermodynamic properties of Capsicum baccatum L. var. pendulum (Willd.) Eshbaugh

Abstract

The objective of this research was to evaluate the drying kinetics of Capsicum baccatum var. pendulum (Willd.) Eshbaugh seeds, as well as to determine their thermodynamic properties. The seeds were placed in polyethylene trays and subjected
to drying at temperatures of 30, 40, 50 and 60 °C. The seeds were periodically weighed, at 20-minute intervals,
until they reached an equilibrium moisture content between 0.4%, 21% and 42%. Mathematical models were fitted to the experimental data to describe the drying processes and the best model was chosen through statistical criteria. The midilli model presented the best fit to the experimental data. With this model, together with the Arrhenius equation,
the effective diffusion coefficient and the thermodynamic properties of the C. baccatum var. pendulum seeds were obtained. It was observed that the values of the effective diffusion coefficient increased with the elevation of the drying air temperature, which varied between 0.751 10-10 and 2.882 10-10 m2 s-1. The activation energy value was 39.02 KJ mol-1. The increase in drying temperature led to a decrease in enthalpy and entropy values, on the other hand, there was an increase in the values of Gibbs free energy.