Conventional hydrothermal methods are lengthy and require high energy consumption. In this study, a quick and energy-saving direct vapor-heat moisture treatment (DV-HMT) method was used to improve the pasting and gelling properties of potato starch under the condition of high temperature (130 °C) and short periods (1, 3, 5, and 7 min). X-ray diffraction analysis exhibited that the relative crystallinity of DV-HMT starches decreased with the extension of treatment time. Small angle X-ray scattering measurements showed that the average thickness of the crystalline lamellae decreased from 6.193 to 5.937 nm, while the average thickness of the amorphous lamellae increased from 3.160 to 3.395 nm. Rapid visco-analyzer measurements exhibited that the breakdown values decreased to 0 mPa s for DV-HMT starches, indicating that this hydrothermal treatment led to starches with high resistance to heating and shearing. The gel hardness of starch treated by DV-HMT for 3 min (266 g) was around 5.4-fold higher than for non-treated starch (41 g). Considering the simple operation of DV-HMT and the short treatment periods (≤ 7 min) used in this study, DV-HMT could be a superior option to enhance the physicochemical and functional properties of starch.
Keywords: hydrothermal treatment; physical modification; starch.
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