关键词: 茶叶；茶多糖；结构特征

Abstract: 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.

Key words: tea; tea polysaccharides; structural characteristics