Modeling of moisture diffusivities for components of yellow-dent corn kernels

The objective of this study was to develop a method to characterize the diffusivity of different components of yellow-dent corn kernels. The equation D = D-0 e(-C/T)M(n), was proposed to describe the moisture diffusivity of yellow-dent corn kernel components. In the equation D (m(2)/s), T (K), and M (dry basis) are moisture diffusivity, temperature, and moisture content, respectively; whereas D-0 (m(2)/S), C (K), and n are parameters for each component. In order to determine these parameters, each component was separated from the corn kernels and its drying curves were measured at controlled conditions using a Moisture Sorption Analyzer. The parameters were determined by an optimization algorithm that minimized the sum of squares of differences between the measured and calculated moisture contents. As moisture sorption data can provide typical drying curves obtained under well specified and controlled external conditions, the minimization algorithm involved the inversion of the typical drying equation governing the transfer of moisture through the corn kernel. Thus, Fick's second law of diffusion, solved using the COMSOL Multiphysics package, was used to describe moisture transfer in the drying samples. Information obtained in this study is needed to model moisture transfer within corn kernels during the drying process and minimize drying-induced stress cracks. (C) 2009 Elsevier Ltd. All rights reserved.