The effect of acid hydrolysis on native starch granule structure

A study has been made of the effect of hydrolysis on the structure of three types of starch and their subsequent gelatinisation behaviour. The techniques utilised are simultaneous small and wide angle X-ray scattering (SAXS and WAXS respectively) using a synchrotron source, and differential scanning calorimetry. By fully fitting the small angle scattering curve to identify the behaviour of the different regions within the starch granule, it is possible to understand how the SAXS peak can get less pronounced upon hydrolysis, while the WAXS peaks get more intense. The breadth of the DSC gelatinisation endotherm also increases with extent of hydrolysis. All three findings can be related to the preferential destruction of the amorphous background region during the hydrolysis process.