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Structural transformations at different organizational levels of ethanol-treated starch during heating

Sarifudin, Achmat, Soontaranon, Siriwat, Rugmai, Supagorn, Tongta, Sunanta
International journal of biological macromolecules 2019 v.132 pp. 1131-1139
Silene chalcedonica, corn, crystal structure, heat, light microscopy, models, potato starch, small-angle X-ray scattering, starch, temperature, water
Heating ethanol-treated starch (ETS) is the simplest method to produce granular cold-water swelling starch. Structural transformations of ethanol-treated maize and potato starch (ETMS and ETPS) at the crystalline, lamellae and granular structural levels during heating were investigated through in situ wide- and small-angle X-ray scattering (WAXS and SAXS) combined with light microscopy (LM). The result of in situ WAXS indicated that the native crystalline structure was slowly disrupted up to 82 and 60 °C for ETMS and ETPS, respectively. The initial temperature for the formation of a V-type crystalline structure of ETMS was observed to be 86 °C. The result of paracrystalline analysis suggested that the crystalline lamellae of ETS realigned toward a more ordered register when heated to 80 °C and 70 °C for ETMS and ETPS, respectively. The granular forms of ETMS and ETPS were still preserved at 100 °C, although the characteristic of Maltese cross was not observed. A model was proposed to elucidate transformations of ETS at the three structural levels of starch during heating.