用热水从假酸浆籽中提取胶质多糖(NPG)，对其结构和成胶特性进行研究。采用高效液相色谱、高效凝胶渗透色谱、红外光谱、核磁共振碳谱对其化学结构特征进行解析。通过原子力学显微镜观察和透射电镜对假酸浆胶质多糖的成胶特性进行研究。结果表明假酸浆胶质多糖分子量为1.6×106 u，主要由半乳糖醛酸、葡萄糖、半乳糖和鼠李糖这四种单糖构成，其摩尔比为12:4:1:1。该胶质多糖的主链是由半乳糖糖醛酸通过1→4糖苷键连接而成。假酸浆胶质多糖分子的空间结构为球形结构，在钙离子存在下，多糖分子首尾相连，成带分支状结点的链状结构，分支相互交联形成具有空间的网状结构。随着钙离子浓度的升高，交联进一步加深，多糖纤维状结构加厚聚集，形成凝胶。

A pectic polysaccharide (named NPG) was isolated from the seed of Nicandra physaloides (L.) Gaertn by hot water extraction. Its structural characteristics were investigated and elucidated by HPLC, HPGPC, IR, and 1D 13C-NMR, while gelatinization properties were studied by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The results indicated that NPG had a molecular weight of 1.6×106 u and was mainly composed of galacturonic acid, glucose, galactose, and rhamnose at a molar ratio of 12:4:1:1. 13C-NMR spectrum analysis showed that NPG had a backbone composed of 1→4 linked galacturonic acid. NPG presented a regular spherical structure. In the presence of calcium ions, the spherical molecules of NPG linked end-to-end, forming a chain structure with branching nodes. The chain structure cross-linked further with an increase in calcium ions and integrated to form a network of fibrous structures. Subsequently, the fibrous structures were accumulated and dehydrated, thereby forming the gel.

浙江省自然科学基金（Q14H300001）；国家自然科学基金项目（41406142）