Insight into multi-scale structural evolution during gelatinization process of normal and waxy maize starch.

By using a mimicked heating with ex-situ liquid nitrogen flash freezing method, multi-scale structural evolution behaviors of normal maize starch (NMS) and waxy maize starch (WMS) during gelatinization process were studied. The results from SEM, X-ray diffraction (XRD), FTIR/solid state NMR spectroscopy and small angle X-ray scattering (SAXS) showed that NMS and WMS exhibited differently structural evolution behavior during gelatinization process. As the temperature increase, the proportion of the NMS granules with cavity gradually increased, while after heating beyond (peak gelatinization temperature (Tp) + conclusion gelatinization temperature (Tc))/2 the disappearance of starch granule integrity occurred for WMS. The relative crystallinity of NMS declined from 32.8 to 15.26% gradually, as that of WMS declined from 42.43 to 13.09% with a sharply descent when heated beyond (Tp + Tc)/2. The loss of short-range order structure of NMS and WMS showed same trends according to FTIR and NMR. Semicrystalline lamellae of NMS became thinner gradually while that of WMS showed an apparently narrowing after heating beyond (Tp + Tc)/2. These results suggest that the destruction of double helix in amylopectin structure had greatly influence on the larger scale structure of starch samples. This strategy is important for thorough understanding and profiting starch-based food processing. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05520-2. © Association of Food Scientists & Technologists (India) 2022.