Cinética de secagem de folhas de guaçatonga (Casearia sylvestris swartz var. língua)

Abstract

The aim of this study was to analyze the drying kinetics of Guaçatonga leaves (Casearia sylvestris swartz var. língua) at different temperatures and drying air speeds. The study is being carried out at LAPREP - Laboratório de Pré-Processamento e Armazenamento de Produtos Agrícolas (FCA/UFGD). Guaçatonga leaves are used, randomly harvested from different plants in the early morning, always at the same time. A drying rate study is carried out in a test dryer using a combination of four temperatures (40, 50, 60, 70 °C) and two drying air speeds (0.4 and 0.8 m s-1). The product is dried to a moisture content of approximately 0.10 decimal b.s. A mathematical model traditionally used to describe the drying of agricultural products is fitted to the experimental moisture ratio data. In addition, the rate of water loss, the effective diffusion coefficient and activation energy determined. The results are subjected to linear and non-linear regression analysis to check which models provide a satisfactory statistical fit to the observed data. The model that best fitted the drying curve was the Midilli model and there was a decrease in the drying time and an increase in the effective diffusion values as the temperature and drying air velocity increased, as well as a reduction in the activation energy during drying as the drying air velocity increased.