Abstract Freeze-drying treatment results in a marked disordering of starch structures because of the freezing of water and the sublimation of ice crystals. The objective of this work is to evaluate how the freeze-drying affects short-range ordered and crystalline structure, the structural compactness, size of reassemblied aggregates, and mesh size of starch gel network, by use of fourier transform infrared spectroscopy, small angle X-ray scattering and X-ray diffraction. Gels prepared from normal (NMS gel) and high-amylose maize starch (G50 gel) were selected as the model materials. After freeze-drying treatment, the short-range ordered and crystalline structures, the structural compactness, and the mesh size of starch gel network reduced for both starch gels. Long-range periodicity of reassemblied aggregates decreased via thinned amorphous region but unchanged ordered region. Impressively, G50 gel which had more ordered structures and a stronger gel network exhibited a higher resistant ability to the destruction of freeze-drying, and then showed little changes in microstructures after being freeze-dried in comparison with NMS gel. The ordered structures, compact reassemblied aggregates, and high-density mesh size-containing gel network may show a higher resistance to the destruction effect of freeze-drying treatment. This work systematically reveals the structural changes of starch gels subjected to freeze-drying treatment, which provides an in-depth understanding of gels structural changes during processing.

中文翻译：

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了解冷冻干燥对淀粉水凝胶微结构的影响

摘要 冻干处理由于水的冻结和冰晶的升华导致淀粉结构显着紊乱。这项工作的目的是通过使用傅立叶变换红外光谱、小角 X 评估冷冻干燥如何影响短程有序和晶体结构、结构致密性、重组装聚集体的大小和淀粉凝胶网络的网孔大小。射线散射和 X 射线衍射。选择由普通（NMS 凝胶）和高直链玉米淀粉（G50 凝胶）制备的凝胶作为模型材料。冷冻干燥后，两种淀粉凝胶的短程有序结构和结晶结构、结构致密性和淀粉凝胶网络的网孔尺寸均减小。重组装聚集体的长程周期性通过变薄的无定形区域而降低，但有序区域不变。令人印象深刻的是，具有更有序结构和更强凝胶网络的G50凝胶表现出更高的抗冻干破坏能力，与NMS凝胶相比，冻干后微观结构几乎没有变化。有序的结构、紧密的重组装聚集体和含有高密度网格尺寸的凝胶网络可能对冷冻干燥处理的破坏作用表现出更高的抵抗力。这项工作系统地揭示了冷冻干燥处理后淀粉凝胶的结构变化，为深入了解加工过程中的凝胶结构变化提供了依据。结构更有序、凝胶网络更强的G50凝胶表现出更高的抗冻干破坏能力，与NMS凝胶相比，冻干后微观结构几乎没有变化。有序的结构、紧密的重组装聚集体和含有高密度网格尺寸的凝胶网络可能对冷冻干燥处理的破坏作用表现出更高的抵抗力。这项工作系统地揭示了冷冻干燥处理后淀粉凝胶的结构变化，为深入了解加工过程中的凝胶结构变化提供了依据。结构更有序、凝胶网络更强的G50凝胶表现出更高的抗冻干破坏能力，与NMS凝胶相比，冻干后微观结构几乎没有变化。有序的结构、紧密的重组装聚集体和含有高密度网格尺寸的凝胶网络可能对冷冻干燥处理的破坏作用表现出更高的抵抗力。这项工作系统地揭示了冷冻干燥处理后淀粉凝胶的结构变化，为深入了解加工过程中的凝胶结构变化提供了依据。致密的重组装聚集体和含有高密度网格尺寸的凝胶网络可能对冷冻干燥处理的破坏作用表现出更高的抵抗力。这项工作系统地揭示了冷冻干燥处理后淀粉凝胶的结构变化，为深入了解加工过程中的凝胶结构变化提供了依据。致密的重组装聚集体和含有高密度网格尺寸的凝胶网络可能对冷冻干燥处理的破坏作用表现出更高的抵抗力。这项工作系统地揭示了冷冻干燥处理后淀粉凝胶的结构变化，为深入了解加工过程中的凝胶结构变化提供了依据。