摘要：Background: Water desorption isotherm of Glutinous Rice Flour (GFR) is necessary for processing and storage design for foods such as tangyuan (a traditional Chinese dessert). Methodology: The GRF was equilibrated under 10 water activity (aw) levels at 10, 20 and 30°C. Isotherm data was modeled with four theoretical isotherm equations (GAB, GDW, Aouaini and CMMS). Results: The values of monolayer water content obtained from the four models differed from each other due to their different assumption. All the four models predicted endothermic interaction of water with primary adsorption sites in GRF during desorption and weakly temperature-dependent water-water interaction, but gave much different adsorption enthalpy related to the primary adsorption. Within the assumption of the GDW model, not more than 20% strongly bound water molecules became secondary adsorption sites. In the scenario of the Aouaini model, the water molecules were adsorbed in a perpendicular position to the surface of GRF solids with decreased crowdedness as temperature increased and the number of layers beyond the first layer showed a very weakly temperature-dependent behavior. Conclusion: Although mechanism-based isotherm models can give more details on distribution of water molecules in adsorbed layers and water-water, water-sorbent interactions, additional technical observations are required to verify the predictions of a theoretical model.
