Rheological characterization of schizophyllan aqueous solutions after denaturation-renaturation treatment
Rheological characterization of schizophyllan aqueous solutions after denaturation-renaturation treatment
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DOI：
10.1002/bip.20081
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发表时间：
2004-07-01
期刊：
影响因子：
2.9
通讯作者：
Nishinari, K
中科院分区：
文献类型：
--
作者：
Fang, YP;Takahashi, R;Nishinari, K
将分子量为2.6 × 10（6）的裂褶多糖（SPG）（命名为SPG-1）变性，然后通过碱化-中和以1.8重量%的浓度复性。将制备的变性-复性样品（DRSPG-1）稀释至各种浓度并平衡10天，然后测量流变学和特性粘度。当浓度（C-p）大于0.75wt%时，DRSPG-1水体系具有弱凝胶型流变性质。然而，对于小于或等于0.28wt%、小于或等于0.65wt%和小于或等于0.19wt%的C-p，DRSPG-1水体系分别表现为幂律流体和牛顿流体，这归因于DRSPG-1链的中等各向同性程度。此外，确定了DRSPG-1在水溶液中的临界重叠参数c*[eta] = 1.2，其接近于完整SPG在水中的I，而远小于SPG在DMSO中的4.3。这被认为是由于DRSPG-1链在水中的强相互作用，通过特性粘度测量进一步证实，其中DRSPG-1水溶液显示出异常大的Huggins常数值。关于DRSPG-1弱凝胶的结构，多轮动态应变扫描测量表明，主要结构是由DRSPG-1链的氢键缔合而不是永久的三维网络形成的聚集体。此外，还进行了阶跃剪切速率实验，研究了DRSPG-1水溶液体系的触变性能。（D 2004 Wiley Periodicals，Inc.
Schizophyllan (SPG) with a molecular weight of 2.6 x 10(6), designated SPG-1, is denatured and then renatured at a concentration of 1.8 wt % by alkalization-neutralization. The prepared denatured-renatured samples (DRSPG-1) are diluted to various concentrations and equilibrated for 10 days before rheological and intrinsic viscosity measurements. When concentration (C-p) is above 0.75 wt %, DRSPG-1 aqueous systems have weak gel-type rheological properties. However, for 0.28 wt % less than or equal to C-p less than or equal to 0.65 wt % and C-p less than or equal to 0.19 wt %, DRSPG-1 aqueous systems behave as power law fluids and Newtonian fluids, respectively, which are attributed to the moderate isotropy degree of DRSPG-1 chains. Furthermore, a critical overlap parameter of c*[eta] = 1.2 is determined for DRSPG-1 in aqueous solutions, which is close to that of I for intact SPG in water while far smaller than that of 4.3 for SPG in DMSO. This is considered to be due to the strong interactions of DRSPG-1 chains in water, further confirmed by the intrinsic viscosity measurements in which the DRSPG-1 aqueous solution shows an abnormally large value of Huggins constant. Regarding the structure of DRSPG-1 weak gels, multiruns of dynamic strain sweep measurements suggest that the dominant structures are aggregates formed by hydrogen-bonding associations of DRSPG-1 chains rather than the permanent three-dimensional network. In addition, the step-shear rate tests are performed to study the thixotropic properties of DRSPG-1 aqueous systems. (D 2004 Wiley Periodicals, Inc.