Rheological study of gum arabic solutions: interpretation based on molecular self-association.
Rheological study of gum arabic solutions: interpretation based on molecular self-association.
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DOI：
10.1016/j.foodhyd.2009.06.018
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发表时间：
2009-12
影响因子：
10.7
通讯作者：
Xiaobei Li;Yapeng Fang;S. Al-Assaf;G. Phillips;K. Nishinari;Hongbin Zhang
中科院分区：
文献类型：
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作者：
Xiaobei Li;Yapeng Fang;S. Al-Assaf;G. Phillips;K. Nishinari;Hongbin Zhang
本研究涉及阿拉伯胶水溶液的流变特性，阿拉伯胶是一种复杂的阿拉伯半乳聚糖多糖，含有约 2% 的蛋白质。通过流变学和动态光散射方法研究了具有不同分子缔合的对照胶和熟化胶（EM2）在不同浓度的水中和添加尿素（6M）时的流动行为。研究了分子缔合对阿拉伯树胶溶液流变行为的影响。研究发现，尽管在大范围的浓度和高剪切速率下观察到牛顿行为，但阿拉伯树胶溶液在低剪切速率范围内表现出明显的剪切稀化。对于水中的对照胶和 EM2，观察到剪切速率增加和降低过程之间的最大粘度差异为 6%；在尿素溶液中，对照胶为 3%，EM2 为 9%。结果表明，溶液中存在阿拉伯树胶的大分子缔合，观察到的随时间变化的流动行为反映了系统中微观结构的破坏和重建。这种现象是根据流变特性和微观结构特征之间的关系来理解的。提出了一个模型来解释流变行为，该行为归因于剪切诱导的阿拉伯树胶聚集体的破裂和重新形成的发生。
This study deals with the rheological properties of aqueous solutions of gum arabic, the complex arabinogalactan polysaccharide containing about 2% protein. The flow behavior of control gum and a matured gum (EM2), which have different molecular associations, was investigated at different concentrations in water and added urea (6M) by rheological and dynamic light scattering methods. The influence of molecular association on rheological behavior of gum arabic solutions was studied. It was found that though Newtonian behavior was observed across a wide range of concentrations and at high shear rates, gum arabic solutions showed a pronounced shear thinning in low shear rate ranges. The maximum difference in viscosity between shear rate increasing and decreasing processes was observed at 6% for both control gum and EM2 in water, and at 3% for control gum and 9% for EM2 in urea solutions. The results demonstrated macromolecular association of gum arabic occurring in the solutions, and the observed time-dependent flow behavior reflected microstructural breakdown and re-building in the systems. This phenomenon was understood in view of the relationship between rheological properties and microstructural characteristics. A model was presented to interpret the rheological behavior, which is attributed to the occurrence of shear-induced breakdown and re-formation of gum arabic aggregates.