MR imaging and diffusion studies of soaked rice

The effects of lipid on magnetic resonance (MR) images and diffusion data in soaked rice were investigated using MR imaging and pulsed field gradient (PFG)-NMR spectroscopy, as well as water diffusion within rice. Lipid contributed to proton density-weighted MR image and found to be diffused by diffusion-ordered spectroscopy (DOSY). During diffusion experiments, two components for the self-diffusion coefficient (Ds1 and Ds2) of water and one component for lipid (Ds3) were observed in soaking rice. It suggests that Ds2 of water self-diffusion corresponds to water diffusion within starch granules of rice, resulting in a restricted diffusion. Based on the restricted diffusion, the average size (a) of the starch granules was estimated to be 4.6 μm. The permeability of water (P) of starch granule was increased from 1.77 × 10−5 m/s to 2.49 × 10−5 m/s as the soaking time increased from 3 to 6. This study demonstrates that lipids play a role in MR images contrast and diffusion data, and that physicochemical properties of the starch granule can be characterized in soaked seeds by PFG-NMR.