Han Zhuo-Xiao, Rana Mohammad M, Liu Guo-Feng, Gao Ming-Jun, Li Da-Xiang, Wu Fu-Guang, Li Xin-Bao, Wan Xiao-Chun, Wei Shu
State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, China.
State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 Changjiang Ave W., Hefei, Anhui 230036, China; Bangladesh Tea Research Institute, Srimangal-3210, Moulvibazar, Bangladesh.
Food Chem. 2016 Dec 1;212:739-48. doi: 10.1016/j.foodchem.2016.06.049. Epub 2016 Jun 16.
Flavour determinants in tea infusions and their changes during manufacturing processes were studied using Camellia sinensis cultivars 'Bai-Sang Cha' ('BAS') possessing significant floral scents and 'Fuding-Dabai Cha' ('FUD') with common green tea odour. Metabolite profiling based on odour activity threshold revealed that 'BAS' contained higher levels of the active odorants β-ionone, linalool and its two oxides, geraniol, epoxylinalool, decanal and taste determinant catechins than 'FUD' (p<0.05). Enhanced transcription of some terpenoid and catechin biosynthetic genes in 'BAS' suggested genetically enhanced production of those flavour compounds. Due to manufacturing processes, the levels of linalool and geraniol decreased whereas those of β-ionone, linalool oxides, indole and cis-jasmone increased. Compared with pan-fire treatment, steam treatment reduced the levels of catechins and proportion of geraniol, linalool and its derivatives, consequently, reducing catechin-related astringency and monoterpenol-related floral scent. Our study suggests that flavour determinant targeted modulation could be made through genotype and manufacturing improvements.
以具有显著花香的茶树品种‘白桑茶’（‘BAS’）和具有普通绿茶香气的‘福鼎大白茶’（‘FUD’）为材料，研究了茶汤中的风味决定因素及其在加工过程中的变化。基于气味活性阈值的代谢物分析表明，‘BAS’中活性气味物质β-紫罗兰酮、芳樟醇及其两种氧化物、香叶醇、环氧芳樟醇、癸醛和味觉决定因素儿茶素的含量均高于‘FUD’（p<0.05）。‘BAS’中一些萜类和儿茶素生物合成基因的转录增强，表明这些风味化合物的基因产量增加。由于加工过程，芳樟醇和香叶醇的含量降低，而β-紫罗兰酮、芳樟醇氧化物、吲哚和顺式茉莉酮的含量增加。与锅炒处理相比，蒸汽处理降低了儿茶素的含量以及香叶醇、芳樟醇及其衍生物的比例，从而降低了儿茶素相关的涩味和单萜醇相关的花香。我们的研究表明，可以通过基因型和加工改进来实现风味决定因素的靶向调控。
