Abstract The interaction between macromolecular chains of gelatin and anionic polysaccharide sodium alginate during the formation of polyelectrolyte complexes was examined using UV and FTIR spectroscopy. It has been shown that in an aqueous phase, where the pH is slightly higher than the pI of gelatin, complexes are formed through hydrogen bonds as well as electrostatic interactions between two biopolymers. The complex formation is accompanied by a change in the secondary structure of gelatin. At a low weight (w/w) ratio of polysaccharide to gelatin (up to 0.2) a decrease in the share of collagen-like helices and an increase in the share of the random coil conformation of gelatin chains were reported. SEM was used to identify a fundamental distinction between the morphologies of the gelatin hydrogel and the mixed alginate–gelatin hydrogel with a low mass ratio of biopolymers. Spherical formations were found in the structure of the latter that were interpreted as aggregations of complexes. Graphical Abstract

中文翻译：

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明胶和海藻酸钠之间的相互作用：UV 和 FTIR 研究

摘要 使用紫外和红外光谱研究了在聚电解质复合物形成过程中明胶大分子链与阴离子多糖海藻酸钠之间的相互作用。已经表明，在 pH 略高于明胶 pI 的水相中，复合物是通过氢键以及两种生物聚合物之间的静电相互作用形成的。复合物的形成伴随着明胶二级结构的变化。据报道，在多糖与明胶的低重量 (w/w) 比（高达 0.2）下，胶原样螺旋的份额减少，而明胶链的无规卷曲构象的份额增加。SEM 用于确定明胶水凝胶和具有低生物聚合物质量比的混合藻酸盐-明胶水凝胶的形态之间的基本区别。在后者的结构中发现了球形结构，被解释为复合物的聚集体。图形概要