Abstract Protein-protein crosslinks, especially disulfide bonds, widely exist and influence the quality of cereal-based food. In order to investigate the effect of disulfide bonds on pasting properties of foxtail millet, ten typical varieties were selected and separated into three groups according to their eating quality, and then reducing agent dithiothreitol (DTT) was used to disrupt disulfide bonds. Disulfide and sulfhydryl groups’ variations, pasting, and hydration properties were determined. Scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) were also used to analyze the microstructure of foxtail millet paste. Results showed that foxtail millet with poor eating quality was more prone to form disulfide bond linkage at a higher rate and degree during cooking. Disrupting disulfide bonds increased peak viscosity, breakdown, water absorption, and swelling power of granules. Meanwhile, pasting temperature, setback, and final viscosity decreased significantly. The larger size of swollen starch granules and breakage of protein networks were found under CLSM, and firmer lamellar structures with less connections and pores were illustrated under SEM in DTT-treated paste. After DTT-treatment, disulfide bonds were believed to restrict hydration and pasting properties of foxtail millet, and strengthen the swollen granules and paste rigidity as well as a high level of starch reassociation.

中文翻译：

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还原剂DTT对谷子糊化、水化及微观结构特性的影响

摘要 蛋白质-蛋白质交联，尤其是二硫键，广泛存在并影响着谷类食品的品质。为研究二硫键对谷子糊化特性的影响，选取十个典型品种，按其食用品质分为三组，然后使用还原剂二硫苏糖醇（DTT）破坏二硫键。测定了二硫化物和巯基的变化、糊化和水合特性。扫描电子显微镜（SEM）和共聚焦激光扫描显微镜（CLSM）也被用来分析谷子糊的微观结构。结果表明，食用品质较差的谷子在蒸煮过程中更容易以较高的速率和程度形成二硫键。破坏二硫键会增加峰值粘度，颗粒的分解、吸水和溶胀能力。同时，糊化温度、回缩和最终粘度显着降低。在 CLSM 下发现了更大尺寸的膨胀淀粉颗粒和蛋白质网络的断裂，并且在 DTT 处理的糊状物中在 SEM 下显示了更坚固的层状结构，连接和孔隙更少。在 DTT 处理后，二硫键被认为会限制谷子的水化和糊化特性，并增强膨胀的颗粒和糊状物的刚性以及高水平的淀粉再结合。在 DTT 处理的糊状物中，在 SEM 下显示了具有较少连接和孔隙的更坚固的层状结构。在 DTT 处理后，二硫键被认为会限制谷子的水化和糊化特性，并增强膨胀的颗粒和糊状物的刚性以及高水平的淀粉再结合。在 SEM 下，在 DTT 处理的糊状物中显示了具有较少连接和孔隙的更坚固的层状结构。在 DTT 处理后，二硫键被认为会限制谷子的水化和糊化特性，并增强膨胀的颗粒和糊状物的刚性以及高水平的淀粉再结合。