茶多糖结构特征研究进展

茶多糖是一类复合型多糖,结构十分复杂,本文介绍了影响茶多糖含量的因素以及茶多糖结构的解析方法和特征。茶多糖含量在茶树品种、成熟度、茶树器官、茶叶加工方法和茶树生长环境等多种因素影响下存在差异;其结构组成单元包括8 种中性单糖、2 种糖醛酸、1.87%～38.00%蛋白质、18 种氨基酸和少量无机元素等,分子质量为2.56～3 900.00 kDa;糖链由单糖通过(1→2)、(1→3)、(1→4)、(1→2,4)等多种方式通过O原子连接而成,且存在分支;有些茶多糖分子存在三股螺旋结构;茶多糖分子会缠绕结合在一起形成形状各异、大小不一的聚集体;结构解析方法包括色谱、光谱、核磁共振、原子力显微镜、扫描电子显微镜等。此外,本文还简要归纳了茶多糖的构效关系,以期为后续茶多糖的结构特征和生物活性研究提供参考。

Progress in Research on the Structural Characteristics of Tea Polysaccharides

Tea polysaccharides are a class of compound polysaccharides with very complex structures. This article reviews the factors that influence the polysaccharide content in tea, the analytical methods to determine the structure of tea polysaccharides and their characteristics. The content of polysaccharides in tea varies depending on various factors such as tea plant varieties, maturity, tea plant organs, tea processing methods and the tea plant growth environment. The structural unit of tea polysaccharides consists of eight neutral monosaccharides, two alduronic acids, 1.87%–38.00% protein, 18 amino acids and a small amount of inorganic elements. Their molecular masses are in the range of 2.56–3 900.00 kDa. Their sugar chains are composed of monosaccharides linked through the oxygen atoms by glycosidic bonds such as (1→2), (1→3), (1→4), (1→2,4), and contain branches. Some tea polysaccharide molecules have a triple helix structure, which can intertwine and bind together to form aggregates of various shapes and sizes. The structure of tea polysaccharides is usually analyzed by chromatography, spectroscopy, nuclear magnetic resonance, atomic force microscopy, and scanning electron microscopy. In addition, this article also briefly summarizes the structure-activity relationship of tea polysaccharides, in order to provide a basis for further research on the structure characteristics and biological activities of tea polysaccharides.