Sorption Properties of Cape Gooseberry (Physalis peruviana L.)

The sorption equilibrium of water for cape gooseberry at different temperatures (25, 35, 50 and 60 degrees C) over a range of relative humidity levels, from 0.10 to 0.90, were determined using a gravimetric static method. The isosteric heat and Gibbs free energy were calculated from the sorption equilibrium. GAB, BET, SMITH, modified de Halsey, modified de 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 were calculated using the BET model. The sorption curves show a Type III behavior. The isosteric heat decreased with increases in moisture content, while the Gibbs free energy increased.