(492c) Modeling of Sorption Heat in Foods Using a Molecular Thermodynamics Approach

Moisture content in foods and similar biomass substrates affects many aspects of their processing and handling. Among them, drying is required for quality, conditioning, and transportation among others. The heat of vaporization of water in these substrates depends strongly on the water chemical activity, which is affected by many aspects such as adsorption, mixing, ionic strength, and several other variables that affect the water interactions in the matrix of the material. In this work, we use a molecular thermodynamics framework to estimate the heat of vaporization of water during desorption or drying processes. This is an extension of previous modeling work by the authors on modeling of equilibrium moisture in foods and similar materials. The advantage of this approach is that by taking into account other non-adsorption phenomena one can estimate separately the different contributions to the heat of vaporization during desorption processes gaining more fundamental insight in how changes in the water activity affects the energy requirements for drying and other operations. We modeled the heat of sorption for various foods. The results show that the modeling framework results are in line with experimental data and it provides more physical insight on the different interactions of water in the substrate towards the energy consumption during drying and similar operations.