Equilibrium moisture content and heat of sorption of Gelidium sesquipedale

Moisture equilibrium data for adsorption and desorption of water from Gelidium sesquipedale were investigated at temperatures in the range of 30-50°C and water activity ranging from 0.05 to 0.9. The experimental procedure used was based on the gravimetric static method. The sorption curves of Gelidium sesquipedale decreased with increase in temperature at constant relative humidity. The hysteresis effect was observed. The experimental data of sorption were described by six models. The GAB and modified BET models were found to be the most suitable for describing the sorption curves. The isosteric heats of desorption and adsorption of water were determined from the equilibrium data at different temperatures.