Abstract In this paper, Na+-induced gelation of a low-methoxyl pectin extracted from Premna microphylla Turcz were studied by rheological analysis, texture test, microstructure observation, thermodynamics study and gelling forces analysis. The results showed that Na+ could induce the gelation of ammonium oxalate extraction pectin from Premna microphylla Turcz (AOP) at room temperature. Besides, The Na+ concentration had a significant effect on the generation of AOP gel. There was an optimal Na+ concentration (0.6 M) for AOP to form a gel with the highest solid-like properties, water holding capacity (WHC) and crystallinity. With the further increase of Na+ concentration from 0.6 M to 0.7 M, the gel properties of the pectin gel would be weakened. Gelling forces analysis revealed that Na+-induced gelation of AOP was mainly caused by electrostatic shielding and hydrogen bonds. When sufficient content of Na+ was added to AOP, the electrostatic shielding effect of Na+ would reduce the expansion degree of AOP chains and make the pectin molecules get close to each other. Subsequently, hydrogen bonds in and between the pectin chains would be formed, thus building up the gel. The results of this study can provide references and methods for the mechanism study of monovalent cation-induced gelation of pectin.

中文翻译：

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Na + 诱导从 Premna microphylla Turcz 中提取的低甲氧基果胶的凝胶化

摘要 本文通过流变学分析、质构测试、微观结构观察、热力学研究和胶凝力分析，研究了Na+诱导的小叶Premna microphylla Turcz提取的低甲氧基果胶的凝胶化作用。结果表明，Na+在常温下可诱导小叶草(Premna microphylla Turcz)草酸铵提取果胶(AOP)凝胶化。此外，Na+浓度对AOP凝胶的生成有显着影响。AOP 的最佳 Na+ 浓度 (0.6 M) 可以形成具有最高固体状特性、持水能力 (WHC) 和结晶度的凝胶。随着 Na+ 浓度从 0.6 M 进一步增加到 0.7 M，果胶凝胶的凝胶特性会减弱。凝胶力分析表明，Na+诱导的AOP凝胶化主要是由静电屏蔽和氢键引起的。当AOP中加入足够量的Na+时，Na+的静电屏蔽作用会降低AOP链的膨胀程度，使果胶分子相互靠近。随后，果胶链中和之间的氢键将形成，从而形成凝胶。本研究结果可为单价阳离子诱导果胶凝胶化的机理研究提供参考和方法。果胶链内部和之间会形成氢键，从而形成凝胶。本研究结果可为单价阳离子诱导果胶凝胶化的机理研究提供参考和方法。果胶链内部和之间会形成氢键，从而形成凝胶。本研究结果可为单价阳离子诱导果胶凝胶化的机理研究提供参考和方法。