The effect of degree of esterification (DE) on the cryoprotective function of pectin against the frozen deterioration of gluten protein is still unclear. Here, NMR, HPSEC-MALLS, HPGPC and optical microscrope were applied to determine the structure and ice recrystallization inhibition (IRI) activity of pectin with varying DE. The effect on structure, physicochemical properties and molecular interaction of gluten supplemented with pectin were investigated. Results suggested that low-ester pectin (LEP) exhibited higher IRI activity than that of high-ester pectin (HEP), and reduced the damage of gluten during freezing storage. Moreover, SEM and low field-NMR revealed that LEP effectively helped to maintain the network structure and inhibited the water migration of gluten. Besides, molecular docking results suggested higher affinity between LEP and gluten protein than that of HEP. These results illustrated better cryoprotective effects of LEP than that of HEP through pathways including IRI activity, water migration, and possible molecular interaction.

中文翻译：

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不同酯化度果胶对面筋蛋白冻融稳定性的影响：结构、功能特性及冷冻保护机制


酯化度 （DE） 对果胶对面筋蛋白冷冻变质的冷冻保护功能的影响尚不清楚。在这里，应用 NMR、HPSEC-MALLS、HPGPC 和光学显微镜来确定不同 DE 的果胶的结构和冰再结晶抑制 （IRI） 活性。研究了添加果胶的面筋对结构、理化性质和分子相互作用的影响。结果表明，低酯果胶 （LEP） 表现出比高酯果胶 （HEP） 更高的 IRI 活性，并减少了冷冻贮藏过程中面筋的损害。此外，SEM 和低场 NMR 表明 LEP 有效地帮助维持网络结构并抑制面筋的水迁移。此外，分子对接结果表明 LEP 与面筋蛋白之间的亲和力高于 HEP。这些结果表明，LEP 的冷冻保护作用优于 HEP，其途径包括 IRI 活性、水迁移和可能的分子相互作用。