Mostafa Mahrouz

Moisture adsorption–desorption isotherms of prickly pear cladode (Opuntia ficus indica) at different temperatures

Abstract The equilibrium moisture contents of cladode of Opuntia ficus indica were determined using the gravimetric static method at 30, 40 and 50 °C over a range of relative humidity (Rh) from 0.05 to 0.9. The sorption capacity of cladode decreased with increase in temperature at constant Rh. The experimental sorption curves are then described by the GAB, Henderson’s and BET models. The BET model was found to be the most suitable for describing the sorption curves. The monolayer moisture content values for the sorption at different temperatures are calculated.

Adsorption-desorption isotherms and heat of sorption of prickly pear fruit (Opuntia ficus indica)

Abstract The equilibrium moisture contents were determined for prickly pear fruit using the gravimetric static method at t=30, 40 and 50 °C over a range of relative humidities from 0.05 to 0.9. The sorption curves of prickly pear fruit decreased with increase in temperature at constant relative humidity. The hysteresis effect was observed. The GAB, modified Halsey, modified Chung-Pfost, modified Oswin and modified Henderson models were tested to fit the experimental data. The GAB model was found to be the most suitable for describing the sorption curves. The monolayer moisture content values for the sorption at different temperatures are calculated using a modified BET equation. The isosteric heats of desorption and adsorption of water were determined from the equilibrium data at different temperatures.