Desorption isotherms of in natura leaves of Ziziphus joazeiro Mart. and Bauhinia cheilantha

The Brazilian culture has a great appreciation for the use of medicinal plants for curing diseases. The drying process is very important to assure the quality and stability of these species. This study aimed at obtaining the desorption isotherms of in natura leaves of Ziziphus joazeiro Mart. and Bauhinia cheilantha and adjust the experimental data to different mathematical models. The isotherms were obtained at three temperatures (20ºC, 30ºC and 40ºC), under desorption conditions, and the experimental data adjusted to three models (GAB, Oswin and Peleg) by non-linear regression. The coefficient of determination and the mean percentage deviation between the experimental and predicted values were calculated for each curve, in order to evaluate the best-fit model. According to the statistical parameters of analysis, the Peleg model was the one that better described the hygroscopicity of in natura leaves of Ziziphus joazeiro Mart. and Bauhinia cheilantha