High Resolution CPMAS and Solution NMR Studies of Folysaccharides - Part 1: Starch

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Abstract Extensive high resolution NMR measurements, both in the solid-state and in solution, of starch are reported. Starch samples were in the form of wheat starch and soluble starch from potato. Both wheat starch and whole wheat grain samples were run in the CPMAS experiments. Apart from the normal 13C spectra, 50.29 MHz for the CPMAS and 67.89 MHz for the solution, we also measured proton T1 and T1p and 13C T1 in the CPMAS experiments. Slightly different chemical shifts are obtained in the solution work for different solvents - water, NaOH and LiBr, from those reported earlier. All the carbon resonances have been assigned. The most striking results we get in the CPMAS work are that the wheat starch samples, both powder and grain, show three well-resolved resonances almost of equal intensities for the C-1 carbon, around 100 ppm, as opposed to only one in the solution. These results exactly match X-ray data for starch A. The NMR results also indicate that there is a difference in the solid-state and sol...