Department of Nutrition, Faculty of Health Sciences, Aomori University of Health and Welfare, 58-1 Mase, Hamadate, Aomori, 030-8505, Japan.
Lignocell Research Ltd, 391-5 Ofunato, Tsukuba, 300-1267, Japan.
Anal Sci. 2021 Jan 10;37(1):211-219. doi: 10.2116/analsci.20SAR10. Epub 2020 Dec 4.
Various kinds of polysaccharides found in a wide variety of plants, bacteria, crustaceans and insects form hydrogels via physical aggregation in aqueous media. The major mass of hydrogels is water filled, ca. 95 - 99.5%, in a network structure, although the solid shape of the gel is maintained. In this paper, firstly the wide range of gelation mechanisms are briefly described, and then the thermal analysis of representative gel-forming polysaccharides, such as carrageenan, alginate, galactomannan, and pectin, is introduced. By differential scanning calorimetry (DSC), gel-sol and the sol-gel transition temperature of thermoreversible hydrogels are measured and phase diagram is established. It is suggested that binary systems showing sinusoidal gel-sol-gel transition are capable of being assembled. By thermomechanical analysis (TMA), the dynamic modulus (E') at around 1 × 10 Pa of thermo-irreversible hydrogels was obtained using a sample holder designed to measure the viscoelastic properties in water. Reliable coordination is shown between the results obtained by DSC and TMA. In this review, the current research and several topics on concerning the thermal properties of polysaccharide physical hydrogels are introduced.
在各种植物、细菌、甲壳类动物和昆虫中发现的各种多糖通过在水介质中的物理聚集形成水凝胶。水凝胶的主要质量是水，填充约 95-99.5%，在网络结构中，尽管凝胶的固体形状得以保持。在本文中，首先简要描述了广泛的胶凝机制，然后介绍了代表性的形成凝胶多糖，如卡拉胶、藻酸盐、半乳甘露聚糖和果胶的热分析。通过差示扫描量热法（DSC），测量了热可逆水凝胶的胶-溶胶和溶胶-凝胶转变温度，并建立了相图。表明显示正弦凝胶-溶胶-凝胶转变的二元体系能够进行组装。通过热机械分析（TMA），使用设计用于测量水的粘弹性特性的样品架获得了热不可逆水凝胶的约 1×10 Pa 左右的动态模量（E'）。DSC 和 TMA 的结果之间显示出可靠的协调性。在这篇综述中，介绍了多糖物理水凝胶热性质的当前研究和几个相关主题。
