Article,
A magnetic resonance study of water uptake in whole barley kernels
International Journal of Food Science and Technology, 36 (2): 161--168 (2001)
Abstract
The water uptake by barley kernels was followed by 1H NMR spectroscopy.
A model was used to explain the first 7 h of imbibition. Measurement
of the 1H spin-lattice relaxation rate, R1, showed that during the
first 7 h of imbibition, water uptake is dominated by a purely diffusive
process with a ?D - t dependence, where D is the diffusion constant
and t is time. While increasing during the first 7 h of imbibition,
R1 slowly but continuously decreased afterwards. The observed changes
in R1 with imbibition time allowed discrimination between the first
two phases in water uptake, as generally observed in germinating
seeds. The second phase was characterized by a slow but continuous
decrease in R1, indicating a redistribution of water within the kernel.
Observed spin-lattice relaxation rates, R1, were treated as a superposition
of rates from water molecules in two different physical phases; a
mobile and a less mobile phase. Using the Stokes-Einstein Debye theory
for viscosity, the overall water viscosity within the kernel was
determined using the two-phase model to describe water mobility.
