Article,
Moisture diffusion coefficients of single wheat kernels with assumed simplified geometries: Analytical approach
Transactions of the American Society of Agricultural Engineers, 43 (6): 1653--1659 (2000)
Abstract
Using a combination of soaking data and an analytical solution of
the diffusion equation, moisture diffusion coefficients of single
wheat kernels were determined for nine commercial varieties representing
Six market classes of U.S. wheat. Two geometric conditions, the whole
kernel as a prolate spheroid, and the endosperm (also modeled as
prolate spheroidal) and pericarp as separate components, were examined.
Values from the analytical solution for a sphere were adjusted by
a geometrical correction factor to more closely represent the response
of a prolate spheroid. The ranges in diffusion coefficients were
0.39 � 10-10 to 1.04 � 10-10 m2/s for endosperm and 0.04 � 10-10
to 0.28 � 10-10 m2/s for pericarp. Compared to the pericarp, moisture
diffused more rapidly in the endosperm. Soft wheats tended to have
a more permeable pericarp layer than hard wheats, which resulted
in a greater overall rate of diffusion, despite the endosperm of
these two groups being nearly equivalent in diffusion coefficient
value.
