做青对青叶水分状态与乌龙茶品质的影响

Influence of Fine Manipulation of Green Tea Leaves on Water Status and Quality of Oolong Tea

比较不同晒青程度、不同做青方法、不同温湿条件的叶水势和水分含量,结果表明,晒青叶水分状态因减重率和季节而变化,当晒青叶水势下降至—2.06 MPa时不能正常做青,做青方法主导水势变化趋势,闽南做青呈升降频次少而升降幅度大;闽北做青呈升降频次多而升降幅度小,湿度主要影响叶水势高低水平,温度对水势历程的变化幅度有影响。做青方法是品质风格形成的主导因素,温湿条件是品质高低变化的影响因素,在试验基础上提出不同工艺进程叶水势控制参考指标,以获取优良品质。

The water potential and water content of fresh tea leaves under different extent of drying outdoors, different methods of fine manipulation and different temperature and moisture were comparatively studied. The results showed that the water status of the leaves during drying outdoors varied in terms of the percentage of water loss and season. When the water potential decreased to-2.06 MPa, fine manipulation could not be performed properly. The fluctuation of water potential was mainly controlled by the methods of fine manipulation. When tea was finely manipulated with the methods in south Fujian, its water potential fluctuated less frequently with greater range. On the contrary, when the tea was finely manipulated with the methods in north Fujian, its water potential fluctuated more frequently with smaller range. Moisture influenced the level of water potential. Temperature affected the range of the change of water potential during fine manipulation process. Both the temperature and moisture had an effect on the tea quality. The method of fine manipulation was the leading factor for the formation of the quality and style of the tea. Some indices of water potential were proposed for controlling the fine manipulation process on the basis of the experiment, which would be favourable to achieving a good quality.