South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.
Food Chem. 2012 Dec 15;135(4):2268-76. doi: 10.1016/j.foodchem.2012.07.066. Epub 2012 Jul 20.
Aroma is an essential factor affecting the quality of tea (Camellia sinensis) products. While changes of volatile compounds during tea manufacturing have been intensively studied, the effect of environmental factors on volatile contents of fresh tea leaves has received less attention. We found that C. sinensis var. Yabukita kept in darkness by shading treatment for 3 weeks developed etiolated leaves with significantly increased levels of volatiles, especially volatile phenylpropanoids/benzenoids (VPBs). Upstream metabolites of VPBs, in particular shikimic acid, prephenic acid, and phenylpyruvic acid, showed lower levels in dark treated than in control leaves, whereas the contents of most amino acids including l-phenylalanine, a key precursor of VPBs, were significantly enhanced. In addition, analysis by ultra performance liquid chromatography-time of flight mass spectrometry, capillary electrophoresis-time of flight mass spectrometry, high performance liquid chromatography, and gas chromatography-mass spectrometry indicated that volatile and non-volatile metabolite profiles differed significantly between dark treated and untreated leaves.
香气是影响茶叶（Camellia sinensis）产品质量的一个重要因素。虽然茶叶加工过程中挥发性化合物的变化已经得到了深入研究，但环境因素对新鲜茶叶挥发性含量的影响却较少受到关注。我们发现，经过 3 周遮阴处理的 C. sinensis var. Yabukita 会产生黄化叶片，其挥发性物质，特别是挥发性苯丙烷/苯并类物质（VPBs）含量显著增加。VPBs 的上游代谢物，特别是莽草酸、预苯酸和苯丙酮酸，在遮阴处理的叶片中的含量明显低于对照叶片，而大多数氨基酸的含量，包括 VPBs 的关键前体 l-苯丙氨酸，却显著增加。此外，通过超高效液相色谱-飞行时间质谱、毛细管电泳-飞行时间质谱、高效液相色谱和气相色谱-质谱分析表明，遮阴处理和未处理叶片的挥发性和非挥发性代谢物图谱有显著差异。
