Microstructure and rheological properties of psyllium polysaccharide gel
Microstructure and rheological properties of psyllium polysaccharide gel
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DOI：
10.1016/j.foodhyd.2008.10.012
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发表时间：
2009-08-01
影响因子：
10.7
通讯作者：
Smith, Alexandra
中科院分区：
文献类型：
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作者：
Guo, Qian;Cui, Steve W.;Smith, Alexandra
木耳多糖的强凝胶特性与其保健作用和应用密切相关，如在园林行业中用作粘合剂。然而，关于木耳多糖的凝胶性质的信息非常有限。为探讨木耳的凝胶性质，对木耳多糖的碱提凝胶分数(AEG)进行了研究。采用低温扫描电子显微镜(Cryo-SEM)和冷冻替代电子显微镜(TEM)等流变学和低温电子显微镜方法研究了钙离子对AEG凝胶性能的影响。AEG形成了一种纤维状的弱凝胶。AEG在加热和冷却过程中没有明显的熔点，也没有热滞现象。这种凝胶行为的起源是由于木耳多糖的纤维状凝胶结构。结果表明，Ca(2+)对凝胶性能和微观结构有显著影响。凝胶的弹性模量G‘随Ca(2+)浓度的增加而增大。临界应变S随Ca(2+)浓度的增加先增大后减小。加入Ca(2+)后，AEG凝胶对温度变化的抵抗力增强。添加Ca(2+)后，木耳凝胶转变为聚集凝胶。扫描电子显微镜和透射电子显微镜显示，随着Ca(2+)浓度的增加，凝胶条带变粗，结合区密度增大。添加Ca(2+)改变木耳多糖的整体凝胶性质是由于凝胶结构的改变。(C)2008年，爱思唯尔有限公司出版。
The strong gelling property of psyllium polysaccharides is closely related to its health benefits and applications, such as use as a binding agent in the landscape industry. However, information about gelling properties Of psyllium polysaccharides is very limited. To explore the gel properties of psyllium, the alkaline extracted gel fraction (AEG) of psyllium polysaccharides was studied in this investigation. The rheological and low-temperature electron microscopy methods including cryo-scanning electron microscopy (Cryo-SEM) and freeze-substitution for transmission electron microscopy (TEM) were used to investigate Ca(2+) influence on the gel properties of AEG. AEG formed a weak gel with a fibrous appearance. AEG did not have a sharp melting point and exhibited no thermal hysteresis during heating and cooling procedure. The origin of this gelling behaviour was due to the fibrillar gel structure of psyllium polysaccharide. It was found that Ca(2+) had a significant influence on the gel properties and microstructure. Elastic modulus G' of gel increased as Ca(2+) concentration increased. Critical strain S at first increased and then decreased as Ca(2+) concentration increased. AEG gel became more resistant to temperature change on addition of Ca(2+). Psyllium gel changed to aggregated gel with added Ca(2+). The strands of gel appeared thicker and the density of the junction zone increased with increasing Ca(2+) concentration as revealed by SEM and TEM. The changing bulk gelling properties of psyllium polysaccharide by adding Ca(2+) was attributed to the change in gel structure. (C) 2008 Published by Elsevier Ltd.