Exploring the gelatinization behavior of wheat and tapioca starch at different hydration levels

Abstract The impacts of hydration (45 % of water as intermediate level, 80 % for excess water) and botanical origin of starch (wheat WS, tapioca TS) on swelling, leaching and crystallinity loss were studied. A novelty was the wide temperature range (30–90 °C including the reversible domain) and the use of imaging techniques (laser scattering, optical microscopy) for swelling, in addition to the conventional technique (weighting after centrifugation). Swelling before the gelatinization onset was better revealed by using imaging techniques, while swelling in excess water at high temperature (>60–75 °C) differed between the conventional and laser scanning techniques, suggesting overestimation of the former. Gelatinization of high water-demanding starch under intermediate to low hydrations has been poorly documented and little anticipated in breadmaking for which the selected intermediate hydration applies. The study showed that TS at 45 % hydration gelatinized to a lesser extent than WS, with lower increase in granule size (<60 °C) and more heterogeneous granule integrity (>60 °C).