单萜及其衍生物是茶叶香气成分的重要组成,也是表征香气适宜的重要指标。文章对工夫红茶发酵进程中,香气组分变化进行了全程取样分析。通过感官品质评价,定性工夫红茶发酵程度;借助气相色谱-质谱法(GC-MS)手段,分析发酵过程香气组分,结合化学结构特征,筛选出单萜及其衍生物21种;运用偏最小二乘法判别分析(PLS-DA),实现工夫红茶发酵程度的有效预判,并计算出相关性显著的5个单萜类香气组分。研究结果为工夫红茶发酵工序的反馈性调控,提供了理论保障。
关键词:
单萜; 发酵; 判别; 适度; 工夫红茶
As the basic constituents, monoterpenoids are important indicators for the tea aromatic quality. The time course changes of aromatic components were tracking analyzed throughout the fermentation process. Based on organoleptic evaluation, degree of fermentation was classified qualitatively. Using gas chromatography-mass spectrometry (GC-MS), compositions of aroma were screened during fermentation, and 21 monoterpenoids were discriminated by taking chemical structure into consideration. Employing partial least squares discrimination analysis (PLS-DA) to analyze, effective prejudgment of the fermenting degrees was obtained. Five compounds of the monoterpenoids were calculated as the crucial compositions in connection with the prognosis. Result of the research would be the theoretic guarantee for the feedback control of fermentation process of Congou black tea.
[1] Pou K R J. Fermentation: the key step in the processing of black tea[J]. J of Biosystems Eng, 2016, 41(2): 85-92.
[2] 俞露婷. 红茶模拟发酵工序茶黄素形成调控基础研究[D]. 北京: 中国农业科学院, 2016.
[3] 冯林. 工夫红茶通气氧发酵技术及其化学成分变化研究[D]. 重庆: 西南大学, 2012.
[4] Wahab S, Ullah F, Khattak M K, et al.Impact of temperature and fermentation period on the overall quality of black tea[J]. Pure Appl Biol, 2016, 5(4): 1278-1287.
[5] 陈国宝, 邵静娜, 吴全聪, 等. 工夫红茶发酵过程影响品质因子分析研究[J]. 中国茶叶, 2014(5): 16-18.
[6] 钱园凤, 叶阳, 周小芬. 红茶发酵技术研究现状分析[J]. 食品工业科技, 2012, 33(23): 388-392.
[7] Ghosh S, Tudu B, Bhattachaarrya N, et al.A recurrent Elman network in conjunction with an electronic nose for fast prediction of optimum fermentation time of black tea[J]. Neural Computing and Applications, 2017. DOI: 10.1007/s00521-017-3072-y.
[8] 吴勇. 萜烯类化合物与茶叶香气[J]. 化学工程与装备, 2009(11): 123-125.
[9] 沈生荣, 杨贤强. 不同等级龙井茶香气成分的研究[J]. 福建茶叶, 1989(4): 25-30.
[10] 竹尾忠一. 茶树种间香气特征和茶树系统变异同单萜烯醇的关系[J]. 国外农学: 茶叶, 1985(1): 13-15.