中国茶叶中的氟近十年来的研究进展

主要对茶叶中氟的来源,氟含量,氟浸出率以及茶叶降氟措施研究作了详细的综述。大量的研究资料表明,土壤中的氟直接影响到茶叶中氟的含量,茶树吸收氟与土壤的pH值、有机质含量、粘粒含量、成土母质及土壤中的阳离子有关。大气污染影响茶叶氟含量主要是氟通过叶片气孔进入细胞,进而在茶树体内积累。水环境中氟的含量主要受土壤与大气环境的影响。茶叶中的氟含量随着叶片成熟度的增加而增加;茶叶等级越差,氟含量越高;原料粗老的茶类氟含量要比原料较嫩的茶类氟含量高;不同季节、茶树品种对氟吸收也存在差异性;茶树各部位氟累积强度依次为:叶>花蕾>籽>皮>细枝>骨干枝>细根>茎(主轴)>茎(主干)>主根>侧根;茶叶中氟浸出率与冲泡水温、冲泡时间、冲泡次数等有关。在茶叶加工过程中可以通过热水处理,添加化学试剂,改进生产工艺等措施来降低茶叶中的氟含量。此外,尚可以培育含氟量低的茶树品种。

Review of the study on fluorine status in teas from China in the past decade

the F quarry, F content, F extracting ratio and the fluorine-decreasing measures in teas were summarized. The result showed that the F content in soils directly affected its content in teas, which correlated to the pH, organic matter, soil granule, parent materials and positive ion content and so on. When the atmosphere was polluted, F could enter leaves cells via spiracles in the air. The F content in the water was affected by the soil and atmosphere environments. The older the leaves were, the higher F content was. Likewise F content was also high in the high grade teas and tough raw material teas. The order of F accumulation amounts in the tea plant organs was expressed as leaf>bud>seed>skin>with>skeleton branch>radicel>stem>taproot>side root. The F extracting ratio was very closely correlated with infusing temperature, time and times. In order to decrease the fluorine content in teas, many methods were used by boiling water infusion, adding chemical medicine or improving processing and so on, even cultivating the low-fluorine tea plant breed.