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 re-search the adsorption and desorption equilibrium moisture content were determined for two major varieties of Iranian pistachios at ۱۱ to ۸۵ percent relative humidities and a con-stant temperature of ۵۰°C. A significant hysteresis effect between the adsorption and de-sorption processes was observed statistically. For predicting the adsorption and desorp-tion 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 ۵۰°C.