γ-氨基丁酸（GABA）具有显著的降血压功能，但在茶叶中的含量极低，仅为40~50 mg/100 g。为提高黄茶中GABA含量，该研究基于闷黄工序下的氧胁迫环境，从原料季节（春季、秋季）、闷黄方式（湿坯闷黄、干坯闷黄、复合闷黄）、闷黄设施（自然闷黄、机械闷黄、烘笼闷黄）和闷黄条件（温度及时间）等方面对黄茶中GABA的含量影响进行研究，综合感官审评及GABA含量测定结果，得出一套利于GABA含量提升的黄茶闷黄技术参数。结果表明：原料季节、闷黄工序能有效提升茶叶中的GABA含量。其中，春季原料优于秋季原料；湿坯闷黄优于干坯闷黄和复合闷黄；烘笼闷黄、机械闷黄优于自然闷黄；50 ℃、4 h的闷黄条件下有利于GABA的大量形成。综上，以春季鲜叶为原料，采用湿坯闷黄方式，在发酵机50 ℃下闷黄6 h的GABA含量提升效果最佳，达到127.54 mg/100 g。研究结果为功能黄茶的加工探寻了一条新途径，对未来富含GABA黄茶的研发和生产有重要参考意义。

Gamma-aminobutyric acid (GABA) has a significant blood pressure-lowering function, but its content in tea is extremely low (only 40~50 mg/100 g). In order to increase the content of GABA in yellow tea, this study examined the from the effects of the raw materials obtained from different seasons (spring and autumn), the yellowing process (wet yellowing process, dry yellowing process or wet-dry combined yellowing process), the facilities for yellowing (natural yellowing, mechanical yellowing, bamboo cage yellowing), and conditions of yellowing process (temperature and time) on the GABA content in yellow tea in the oxygen stress environment of the yellowing process. Based on the results of the sensory evaluation and the analysis of GABA content, a set of technical parameters for the yellowing process to increase the GABA content in yellow tea were obtained. The results showed that the yellowing process could effectively increase the content of GABA in tea leaves. Among them, the fresh leaves in spring were better raw materials than those obtained in autumn; Wet yellowing process was better than dry yellowing process and wet-dry combined yellowing process; bamboo cage yellowing and mechanical yellowing were better than natural yellowing; The yellowing conditions of 50 ℃ and 4 h were beneficial to the formation of a large quantity of GABA. In summary, using spring fresh leaves, wet yellowing process, fermentation machine for yellowing at 50 ℃ for 6 h could lead to the highest increase in the GABA content (up to 127.54 mg/100 g). The research results have provided a new way for the processing of functional yellow tea and an important reference for the future research, development and production of the GABA-rich yellow tea.

浙江省“三农六方”科技协作项目（CTZB-F190625LWZ-SNY1）