Hysteresis of the sorption isotherms of mango pulp (Mangifera indica L.) manteiga variety

The sorption isotherms are of great importance for predicting drying and storage of a product. Hysteresis is a phenomenon that occurs due to the difference between the curves of adsorption and desorption. This study aimed to analyse the influence of temperature on sorption isotherms and hysteresis of mango pulp manteiga variety. The isotherms were determined by the static method with the use of different acid concentrations. The samples were submitted to temperatures of 20, 30, 40 and 50 degrees C and water activity ranging from 4.3 to 88.8% until the equilibrium moisture content. Six mathematical models for the sorption isotherms (GAB, BET, Halsey, Henderson-Thompson, Oswin and Luikov) were analysed and adjusted to the experimental data using nonlinear regression. The hysteresis was calculated as the area between the curves of adsorption and desorption. According to the obtained results, the GAB model was the one that favored the best fit to the equilibrium isotherms of mango. The area of the hysteresis decreased 51% between temperatures of 20 and 50 degrees C.