Abstract Rheological characteristics of a sodium alginate and a fucoidan extracted from the brown seaweed Cystoseira compressa harvested from Kerkennah island (Sfax, Tunisia) were investigated. Steady-shear flow and dynamical viscoelasticity were evaluated to describe physicochemical properties of the GulA-rich alginate (ManA/GulA, M/G = 0.77) and highly-ramified fucoidan in semi-diluted media depending on polymer concentration, shear rate, temperature, added mono- (KCl and NaCl) and divalent (CaCl2) salts. Alginate solutions exhibited shear-thinning behavior, with a temperature-dependent behavior highly correlated to the power-law model and the Arrhenius relationship. The results showed strong thixotropic and polyelectrolyte properties, influenced by addition of monovalent and divalent cations. The dynamic rheological characteristics showed a fluid-like viscoelastic behavior (tan δ > 1) whereas the critical overlap concentration C* and specific polymer constant ks were respectively 11 g.L−1 and 4.4 using Williamson model. Fucoidan solutions displayed a shear-thinning behavior with a low viscoelasticity character influenced by temperature and monovalent salts. The flow and viscoelastic characteristics of polysaccharides were described by the Ostwald model.

中文翻译：

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突尼斯褐海藻 Cystoseira compressa 水溶性多糖的流变学研究

摘要 研究了从 Kerkennah 岛（斯法克斯，突尼斯）收获的棕色海藻 Cystoseira compressa 中提取的海藻酸钠和岩藻依聚糖的流变学特性。稳定剪切流和动态粘弹性被评估以描述富含 GulA 的海藻酸盐（ManA/GulA，M/G = 0.77）和高度分枝的岩藻依聚糖在半稀释介质中的物理化学性质，具体取决于聚合物浓度、剪切速率、温度、添加一价（KCl 和 NaCl）和二价（CaCl2）盐。藻酸盐溶液表现出剪切稀化行为，温度依赖行为与幂律模型和阿伦尼乌斯关系高度相关。结果显示出强烈的触变性和聚电解质性质，受添加一价和二价阳离子的影响。动态流变特性显示出类似流体的粘弹性行为（tan δ > 1），而使用威廉姆森模型的临界重叠浓度 C* 和特定聚合物常数 ks 分别为 11 gL-1 和 4.4。褐藻糖胶溶液显示剪切稀化行为，具有受温度和一价盐影响的低粘弹性特征。Ostwald 模型描述了多糖的流动和粘弹性特性。