TD-NMR studies of starches from different botanical origins: Hydrothermal and storage effects

The effects of starch origin on water migration and starch transformation were investigated using one- and two-dimensional Time-domain NMR (TD-NMR) methods. The quantification of T-1 and especially of T-2 relaxation times during thermal treatment enabled their interpretation relative to the sorption, gelatinization and retrogradation phenomena of starches in the presence of water, in a level close to that used for bread making (50%, wet basis). Comparison between native wheat, waxy corn and potato starches made possible to link relaxation variations to starch structure and properties as crystallinity, granule size, polymorphism, amylopectin content and water-binding capacity all along heating, cooling and storage processes.