Time-resolved monitoring of structural changes during in situ hydration of starch granules

The water content in starchy substrates impacts their formulation, properties, processing and aging. In particular, the structural characteristics of native starch granules at different lengthscales (lamellar repeat and degree of crystallinity) are generally determined after a several-day equilibration of starch powders (a few hundred milligrams) at controlled relative humidity. Our experiments aim at shedding light on the hydration dynamics by monitoring the structural changes over the course of a few hours, as a function of the amylose/amylopectin ratio and allomorphic type of the granules, to rationalize the equilibration process. Moreover, by simultaneously collecting time-resolved WAXS and SAXS data, we will assess the correlation between the long-range lamellar order and short-range crystal structure in the starch granules upon hydration.