Analysis of mass transfer in air-drying of foods
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Marinos-Kouris, D
(EN)
Vagenas, GK
(EN)
Saravacos, GD
(EN)
A theoretical model for the convective drying of food materials was developed. These materials shrink considerably, as moisture content decreases; for this reason, the proposed model takes shrinkage into account as a fundamental part of the drying operation. This is accomplished by modeling the movement of dry solids and the consequent movement of bound substance during drying. The resulting system of three non-linear partial differential equations is solved numerically and the predicted values of moisture content and temperature are compared with experimental data for the drying of Sultana grapes. The effective moisture diffusivity in the mass of grapes was described by an Arrhenius-type equation. A sensitivity analysis showed that the activation energy for mass transfer was estimated with a high degree of precision. The agreement between the calculated results and the experimental measurements, using various criteria, was very satisfactory.
(EN)
