Investigating the mechanisms of amylolysis of starch granules by solution-state NMR.

Baldwin A. J., Egan D. L., Warren F. J., Barker P. D., Dobson C. M., Butterworth P. J., Ellis P. R.. (2015)

Biomacromolecules, 16, 1614-21

Starch is a prominent component of the human diet and is hydrolyzed by a-amylase post-ingestion. Probing the mechanism of this process has proven challenging, due to the intrinsic heterogeneity of individual starch granules. By means of solution-state NMR, we demonstrate that flexible polysaccharide chains protruding from the solvent-exposed surfaces of waxy rice starch granules are highly mobile and that during hydrothermal treatment, when the granules swell, the number of flexible residues on the exposed surfaces increases by a factor of 15. Moreover, we show that these flexible chains are the primary substrates for a-amylase, being cleaved in the initial stages of hydrolysis. These findings allow us to conclude that the quantity of flexible a-glucan chains protruding from the granule surface will greatly influence the rate of energy acquisition from digestion of starch.

Biomacromolecules, 16, 1614-21

View Publication