The rheological characteristics of polysaccharides which were extracted and separated from Ulva fasciata (UFP) were investigated in aqueous solutions under conditions of concentration, temperature, solution pH and salt concentrations. It was described by the power-law model with a consistency index (k) and a flow behavior index (n). The rheology results showed UFP exhibited as a shear-thickening fluid and a possible mechanism was proposed to explain this phenomenon that might be the collapse of UFP necklace-type structures. UFP characteristics were evaluated by determining the chemical analysis and zeta potential. The findings indicated UFP may consist of partially ulvan, as the results were in accordance with the ulvan structure. Additionally, a rod-climbing effect and cold-set gelation were observed in the UFP semidilute solution. Therefore, the cold-set gelling properties and unique shear-thickening fluid properties in this work could be valuable for the exploration of U. fasciata as a new source of water-soluble gelling polysaccharides.
Keywords: Necklace-type structures; Rheological characteristics; Shear-thickening fluid; Ulva fasciata.
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