A mathematical model for low-pressure superheated steam drying of a biomaterial

Low-pressure superheated steam drying (LPSSD) has recently received much attention as an alternative drying technique for heat-sensitive biomaterials. Although there are a number of works that report studies of this drying technique experimentally, there are a very limited number of works that report attempts to model this drying process. The aim of the present study was therefore to propose the use of a simple three-dimensional liquid diffusion based model to predict the evolutions of the moisture content and temperature of a product undergoing LPSSD. The effect of the product shrinkage was also included directly in the model and the effect of this inclusion on the predictability of the model is shown. The model was found to be able to predict the heat and mass transfer behavior as well as the change of a selected chemical quality, i.e., β-carotene, of a model biomaterial viz., carrot cube reasonably well over some range of moisture content if accurate values of the heat transfer coefficient were used.