CINÉTICA DE SECAGEM E PROPRIEDADES TERMODINÂMICAS DAS FOLHAS DO MELÃO-DE-SÃO-CAETANO (Momordica charantia L.)

Abstract

Momordica charantia L. is a revolutionary plant for its versatility as food and therapeutic applications. The study on the drying process is very important to keep the quality of its leaves during storage. The objective of this research was to evaluate the drying kinetics of the Momordica charantia leaves as well as to determine their thermodynamic properties. The leaves were placed in a gerbox tray and dried in kiln at temperatures of 20, 30, 40 and 50 °C until hygroscopic equilibrium was reached. Several mathematical models were fitted to the experimental data to characterize the drying process. From the Arrhenius model the diffusion coefficients and the activation energy for the calculation of the enthalpy, entropy and free energy of Gibbs were obtained. It is concluded that Midilli was the best model to represent the drying kinetics of the Momordica charantia leaves. Increasing the temperature of the drying air provides the increase of Gibbs free energy and the diffusivity of moisture inside the leaves. Enthalpy and entropy decrease when the temperature increases.