Rheological properties of yam mucilage

Yam is a vegetable that is widely grown around the world. Yam mucilage contains a high mucin concentration that can be useful for supporting the swallowing process. Although the shear and extensional rheology of yam mucilage is essential to its flow, they have not received much attention. Using a commercial rheometer and a filament stretching rheometer, the rheological properties of the mucilage in yam were examined. Yam mucilage exhibits shear-thinning behavior and viscoelastic behavior. In addition, yam mucilage also exhibits stretching phenomena and shows high extensional viscosity. However, the elasticity of yam mucilage decreased when the shear increased. The extensional rheological behavior of the yam mucilage can be predicted by two models, including the Giesekus model and global function. However, the agreement between the model and the experimental data decreases gradually when the Hencky strain increases, even though the model can predict the shear viscosity data well.