The effective moisture transfer diffusion coefficient (Deff) of ready-to-eat breakfast cereals (RTE) is determined either from an individual particle or a bulk of material in the literature. The Deff is assumed to be the same in both cases which can be dependent on the material thickness. In this study, the effect of bed depth of a bulk of two types of RTE cereal on Deff was investigated at several bed depths at 75% RH. Both linear and nonlinear solutions of Fick's 2nd Law were applied to determine Deff from the weight vs time data. The magnitude of Deff increased with an increase in bed depth. Since the captured air between the particles in the bulk volume contributed significantly to the moisture transfer in the system, the overall Deff of the system increased as the total volume of the captured air increased at higher bed depths. The relation was shown to have a square of the thickness dependence.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the financial support for M.A.T.‘s Ph. D. degree provided by Hacettepe University in Ankara, Turkey and the partial funding by The University of Minnesota Agricultural Experiment Station, Project no. 18-72.