以武夷岩茶当家茶树品种肉桂(Camellia sinensis ‘Rougui’)鲜叶制成的乌龙茶为试材，基于顶空固相微萃取法(HS-SPME)结合气相色谱-质谱联用技术(GC-MS)，探讨武夷岩茶炭焙工艺对肉桂乌龙茶挥发性组分的影响。实验中共检测到样本挥发性成分443个，其中包括96个杂环化合物、81个酯类化合物、31个萜类化合物、42个芳香烃类化合物、55个酮类化合物、24个其他烃类化合物、35个醇类化合物、24个醛类化合物、15个酚类化合物、14个胺类化合物、10个酸类化合物、5个含氮化合物、3个含硫化合物等。经主成分分析及聚类分析显示，焙火工艺是影响乌龙茶挥发性成分含量的重要影响因子。随炭焙程度增加，不同类别物质中的多数挥发性成分含量随之显著升高，且以美拉德反应产物等具有茶叶烘炒香的吡嗪类、糠醛类衍生物、吡咯类等化合物最具代表性；同时，部分含量丰富且具有乌龙茶特殊花果香气的醇类、萜烯类物质如香叶醇、反式-橙花叔醇、植物醇、α-法尼烯等，及具清新花香的吲哚含量显著降低。然而，大多数挥发性差异代谢物随炭焙程度增加相对含量显著升高，并不代表茶叶中芳香物质总量增加。研究表明，乌龙茶精制烘焙过程中，香气物质的积累主要来自热作用下的美拉德反应及非酶促的降解和氧化，如黄酮苷类物质水解。
Based on head-space solid phase microextraction / gas chromatography-mass spectrometry (HS-SPME/ GC-MS), oolong tea made from the fresh leaves of a predominant cultivar of Wuyi rock tea, Camellia sinensis ‘Rougui’, was chosen to investigate the effects of Wuyi charcoal baking process on the volatile components of Rougui oolong tea. A total of 443 volatile metabolites were identified, including 96 heterocyclic compounds, 81 ester compounds, 31 terpenoids compounds, 42 aromatics compounds, 55 ketone compounds, 24 hydrocarbons compounds, 35 alcohol compounds, 24 aldehyde compounds, 15 phenol compounds, 14 amine compounds, 10 acid compounds, 5 nitrogen compounds, 3 sulfur compounds and others. According to these 443 metabolites, both principal component analysis (PCA) and hierarchical clustering analysis (HCA) were demonstrated, which indicated that baking process was a key factor affecting the content of volatile components in oolong tea. With the increasing of charcoal baking degree, the contents of most volatile components in different substance classification increased significantly, and the represented components were the products with the baked aroma such as pyrazines, furfural derivatives and furan, which were generated by chemical reaction under thermal treatments like Maillard; Meanwhile, some substances with rich content and special floral and fruit aroma in oolong tea like geraniol, trans-nerolidol, phytol, α-farnesene and indole reduced significantly. The relative content of most volatile components increased significantly with the increasing of the charcoal baking degree, still cannot mean that the increasing in the total amount of aromatic substances in tea. Our research illustrated that the accumulation of aroma substances in oolong tea during the refined baking process mainly comes from the Maillard reaction under thermal treatments, and non-enzymatic degradation and oxidation like glycosides hydrolysis.
[1] 刘勤晋. 溪谷留香——武夷岩茶香从何来? [M]. 北京: 中国农业出版社, 2018: 31.
[2] 黄贤庚, 黄圣亮. 武夷岩茶传统炭焙法的继承和演变[J]. 福建茶叶, 2010(8): 42.
[3] GB/T 23776–2018. 茶叶感官审评方法[S]. 北京: 中国标准出版社, 2018.
[4] Feng Z H, Li Y F, Li M, Wang Y J, Zhang L, Wan X C, Yang X G. Tea aroma formation from six model manufacturing process[J]. Food Chemistry, 2019, 285: 347–354.
[5] 张丽, 张蕾, 罗理勇, 潘从飞, 曾亮. 焙火工艺对武夷岩茶挥发性组分和品质的影响[J]. 食品与发酵工业, 2017, 43(7): 186–193.
[6] 王蔚, 黄旭建, 易国春, 许思敏, 郭雅玲. HS-GC/MS法分析乌龙茶挥发性成分[J]. 天然产物研究与开发, 2019, 31(2): 222–229.
[7] 陈林, 余文权, 张应根, 项丽慧, 王丽丽, 尤志明. 基于SDE和HS–SPME/GC–MS的乌龙茶香气组成特征分析[J]. 茶叶科学, 2019, 39(6): 692–704.
[8] 嵇伟彬, 刘盼盼, 许勇泉, 江用文, 陈建新, 尹军峰. 几种乌龙茶香气成分比较研究[J]. 茶叶科学, 2016, 36(5): 523–530.
[9] 周子维, 刘宝顺, 武清扬, 毕婉君, 倪子鑫, 赖钟雄, 孙云. 基于LOX–HPL途径的武夷肉桂加工中香气物质的形成与调控[J]. 食品与生物技术学报, 2021, 40(1): 100–111.
[10] Lin J, Zhang P, Pan Z Q, Xu H R, Luo Y P, Wang X C. Discrimination of oolong tea (Camellia sinensis) varieties based on feature extraction and selection from aromatic analysed by HS-SPME/GC-MS[J]. Food Chemistry, 2013, 141(1): 259–265.
[11] 汪健仁, 黄金水, 曹青青, 汪芳, 许勇泉. 焙火对铁观音茶汤品质及儿茶素组分的影响[J]. 中国茶叶加工, 2020(1): 19–25.
[12] 宛晓春. 茶叶生物化学[M]. 北京: 中国农业出版社, 2003: 40– 49, 52.
[13] Chen Y J, Kuo P C, Yang M L, Lin F Y, Jason T C. Effects of baking and aging on the changes of phenolic and volatile compounds in the preparation of old Tieguanyin oolong teas[J]. Food Research International, 2013, 53(2): 732–743.
[14] 徐邢燕, 陈思, 俞晓敏, 赵小嫚, 林宏政, 刘国英, 苏峰, 高峰, 孙云, 郝志龙. 不同烘焙程度与等级武夷肉桂茶品质差异分析[J]. 食品科学, 2020, 41(13): 22–28.
[15] 陈泉宾, 陈键, 王丽丽, 邬龄盛, 王振康. 烘焙工艺对乌龙茶糖氨Maillard反应及风味的影响[J]. 茶叶学报, 2018, 59(1): 33–37.
[16] 江山, 宁井铭, 方世辉, 夏涛, 卢雯静, 韦欢. 焙火温度对条形乌龙茶品质的影响[J]. 安徽农业大学学报, 2012, 39(2): 221–224.
[17] 周雪芳. 烘焙对乌龙茶挥发性化合物的影响[D]. 重庆: 西南大学硕士学位论文, 2013.
[18] Yang N, Liu C J, Liu X K, Tina K D, Morten M, Ian F. Determination of volatile marker compounds of common coffee roast defects[J]. Food Chemistry, 2016, 211: 206–214.
[19] 姚月明, 陈永霖. 武夷肉桂名丛的生化特性[J]. 茶叶科学, 1989, 9(2): 151–154.
[20] 邱晓红, 张丹丹, 韦航, 郑德勇, 李小晶, 林燕萍, 叶乃兴. 基于PTR-GOF-MS与GC-MS技术的武夷水仙和武夷肉桂香气特征分析[J]. 天然产物研究与开发, 2018, 30: 1195–1201.
[21] 戴素贤, 谢赤军, 陈栋, 郑如钦, 谢振伦. 七种高香型乌龙茶香气成分的主成分分析[J]. 华南农业大学学报, 1999, 20(1): 113–117.
闽公网安备 35020602000789号