Lumped-parameter approach for prediction of drying kinetics in foods

Drying kinetics of the product are the most important data required for the design and simulation of air dryers. This essential information can be obt ained through simple lab-scale experiments. Nevertheless, due to the uncert ainty of the process, specially when dealing with biological materials, all the necessary data at different operating conditions are not usually avail able. Olt the other hand, drying kinetic models are either too simple to ex pect reasonably good predictions, or too complicated to be applied easily. The key assumptions of a previously developed lumped-parameter model for ai r drying kinetics were revised to examine their application to biological m aterials. A short cut method has been developed to simulate kinetic curves from a minimum number of experimental data. A simple parameter study was ca rried our to detect the most important variables that affect the mass trans fer Blot number in order to predict kinetics data safely. Experimental (hot air) drying curves for bananas, grapes and mushrooms were obtained in a la b scale dryer, at different air temperatures (50 to 70C) and air velocities (1 to 3 m/s). A comparison between experimental and predicted data was don e for different operating conditions.