MICROSTRUCTURAL CHARACTERIZATION OF STARCH SYSTEMS BY NMR RELAXATION AND Q-SPACE MICROSCOPY

Nuclear magnetic resonance (NMR) relaxation and q-space diffusion meas urements have been used to probe the microscopic water distribution in a variety of starch-based systems, including packed beds of native st arch granules with varying water contents, starch gels, and freeze-dri ed starch gels. The q space data for the granular beds is compared wit h a variety of theoretical models and conforms best to unbounded diffu sion in a lower dimensional space. In contrast to some earlier reports , the data for the gelatinized samples are not anomalous and conform t o simple unrestricted diffusion in a three-dimensional space, The pape r concludes with a novel method for probing pore size distribution in freeze-dried starch gels by infusion of acetone. (C) 1998 Elsevier Sci ence Inc.