The Adsorption-Desorption Hysteresis Effect on Pistachio Nuts.

The equilibrium moisture content is an important parameter for several post-harvesting operations for pistachio nuts, such as drying processes and storage. In this research the adsorption and desorption equilibrium moisture content were determined for two major varieties of Iranian pistachios at 11 to 85 percent relative humidities and a constant temperature of 50°C. A significant hysteresis effect between the adsorption and desorption processes was observed statistically. For predicting the adsorption and desorption EMC, the Halsey model was found the most proper equation for adsorption processes for two varieties (Ohadi and Kalehghochi), whereas the Oswin and Smith models were most appropriate for Ohadi and Kalehghochi for desorption processes, respectively, at constant a temperature of 50°C.