Department of Mechanical Engineering, Thuyloi University, Dong Da, Ha Noi, Vietnam.
Biorheology. 2023;59(1-2):29-42. doi: 10.3233/BIR-220006.
Okra is a vegetable that is widely grown around the world. Okra mucilage contains a high mucus concentration that can be useful for supporting the swallowing process. Although the extensional rheology of okra mucilage is essential to its flow, its extensional viscosity has not received much attention.
Using a filament stretching rheometer, the extensional viscosity of the mucilage in okra was examined. The Giesekus model was used to predict this parameter.
The okra mucilage with different concentrations was extracted from fresh okra. The extensional viscosity was measured using a filament breakup apparatus. The diameter of the liquid bridge was measured by a laser micrometer and it was also observed by a high-speed camera. A rotational rheometer was used to measure the shear viscosity. In addition, the master curves for the shear viscosity were plotted to eliminate the influence of solvent and shear rate and evaluate the influence of concentration on the elasticity of okra mucilage. The okra mucilage shear and extensional viscosity were predicted using the Giesekus model.
Every sample of okra mucilage exhibited shear thinning behavior. In addition to having a high extensional viscosity that is hundreds of times higher than its shear viscosity, okra mucilage also exhibited stretching phenomena. The master curves demonstrated that the pseudoplasticity of the okra mucilage increased along with the concentration. The rheological behavior of the mucilage in okra can be explained by the Giesekus model.
Okra mucilage's shear viscosity exhibited shear thinning behavior and a strong extensional viscosity that was significantly higher than its shear viscosity. The shear and extensional viscosity of okra mucilage can be described and predicted using the Giesekus model.
秋葵是一种在世界各地广泛种植的蔬菜。秋葵黏液含有高浓度的黏液，可用于支持吞咽过程。尽管秋葵黏液的拉伸流变学对其流动很重要，但它的拉伸黏度并没有得到太多关注。
使用细丝拉伸流变仪研究了秋葵黏液的拉伸黏度。使用 Giesekus 模型来预测该参数。
从新鲜的秋葵中提取不同浓度的秋葵黏液。使用细丝断裂装置测量拉伸黏度。通过激光测微计测量液桥直径，并通过高速摄像机观察。使用旋转流变仪测量剪切黏度。此外，绘制剪切黏度主曲线以消除溶剂和剪切速率的影响，并评估浓度对秋葵黏液弹性的影响。使用 Giesekus 模型预测秋葵黏液的剪切和拉伸黏度。
每个秋葵黏液样品均表现出剪切稀化行为。除了具有比剪切黏度高数百倍的高拉伸黏度外，秋葵黏液还表现出拉伸现象。主曲线表明，秋葵黏液的假塑性随浓度的增加而增加。秋葵黏液的流变行为可以用 Giesekus 模型来解释。
秋葵黏液的剪切黏度表现出剪切稀化行为和显著高于其剪切黏度的强拉伸黏度。可以使用 Giesekus 模型来描述和预测秋葵黏液的剪切和拉伸黏度。
