没食子酸与大米淀粉的相互作用

该研究探讨了没食子酸对大米淀粉溶解度、膨胀度、糊化特性及流变学特性的影响，并对淀粉-没食子酸复合物的分子结构及晶体结构进行表征。结果表明：没食子酸显著增加了大米淀粉的溶解度，降低了大米淀粉的膨胀度，糊化温度和糊化焓值（p<0.05），表明没食子酸能抑制淀粉的糊化膨胀并降低其热稳定性。没食子酸降低了大米淀粉的糊化粘度值和回生值，说明没食子酸能减少淀粉分子链间的相互交联，并抑制大米淀粉的老化。没食子酸与大米淀粉的混合体系呈现典型的假塑性流体，具有剪切变稀性；没食子酸显著降低了淀粉的储存模量和损耗模量值，没食子酸-淀粉凝胶体系的粘弹性降低，说明没食子酸对淀粉凝胶结构具有破坏作用。红外光谱表明，没食子酸-淀粉复合物在1045/1022 cm-1峰强度比值减小，说明没食子酸可降低大米淀粉的有序性，二者的相互作用以氢键为主。X-衍射图谱表明，复合物在12.7 °处出现新的衍射峰，表明没食子酸能与大米淀粉发生相互作用形成了特殊的晶体结构。该研究可为没食子酸在淀粉基功能性食品中的应用提供理论指导。

Interactions between Gallic Acid and Rice Starch

The effects of gallic acid on the solubility, swelling, gelatinization, and rheological properties of rice starch, and the characteristics of the molecular and crystal structures of gallic acid-starch complexes were investigated. The results demonstrate that gallic acid significantly increased the solubility and reduced the swelling, gelatinization temperature, and gelatinization enthalpy of rice starch (p<0.05). This suggests that gallic acid could inhibit the gelatinization of starch and reduce its thermal stability. Gallic acid decreased the gelatinized viscosity and setback values of the treated rice starch, indicating that gallic acid reduced the cross-linking between the starch chains and inhibited the retrogradation of the rice starch. These gallic acid and rice starch mixtures represent a typical pseudoplastic fluid, and demonstrated the associated shear-thinning characteristics. The addition of gallic acid significantly reduced the storage modulus and loss modulus of starch gels, and the viscoelasticity of gallic acid-starch gel systems. This indicates that gallic acid has a destructive effect on starch gel structure. Infrared spectroscopy showed that the peak intensity ratio of the gallic acid-starch complex, at 1045/1022 cm-1, decreased, suggesting that the addition of gallic acid reduces the order structure of rice starch. In addition, the data suggests that these two products primarily interact via the production of hydrogen bonds. X-ray diffraction demonstrated that these complexes formed a new diffraction peak at 12.7 °, indicating that gallic acid interacts with rice starch to form a unique crystal structure. This study provides theoretical guidance for the application of gallic acid in the improvement of starch-based functional foods.