中国农业科学 ›› 2015, Vol. 48 ›› Issue (20): 4120-4146.doi: 10.3864/j.issn.0578-1752.2015.20.013

• 园艺·贮藏·保鲜·加工 • 上一篇    下一篇

湖龙井茶香气成分的全二维气相色谱-飞行时间质谱分析

朱荫1,杨停1,2,施江1,2,余方林1,3,戴伟东1,谭俊峰1,郭丽1,张悦1,彭群华1,吕海鹏1,林智1

 
  

  1. 1中国农业科学院茶叶研究所/农业部茶树生物学与资源利用重点实验室,杭州 310008
    2中国农业科学院研究生院,北京 100081
    3浙江工商大学食品与生物工程学院,杭州 310018
  • 收稿日期:2015-04-20 出版日期:2015-10-20 发布日期:2015-10-20
  • 通讯作者: 吕海鹏,Tel:0571-86653154;E-mail:teachem108@hotmail.com。林智,Tel:0571-86650617;E-mail:linzhi@caas.cn
  • 作者简介:朱荫,Tel:0571-87967281;E-mail:zhuy_scu@tricaas.com
  • 基金资助:
    国家自然科学基金(31470694)、国家现代农业产业技术体系建设专项(CARS-23)、中国农业科学院创新工程(CAAS-ASTIP-2014-TRICAAS)

Analysis of Aroma Components in Xihu Longjing Tea by Comprehensive Two-Dimensional Gas Chromatography- Time-of-Flight Mass Spectrometry

ZHU Yin1, YANG Ting1, 2, SHI Jiang1, 2, YU Fang-lin1, 3, DAI Wei-dong1, TAN Jun-feng1, GUO Li1, ZHANG Yue1, PENG Qun-hua1, LÜ Hai-peng1, LIN Zhi1   

  1. 1Tea Research Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Tea Biology and Resource Utilization of Ministry of Agriculture, Hangzhou 310008
    2Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081
    3School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018
  • Received:2015-04-20 Online:2015-10-20 Published:2015-10-20

摘要: 【目的】香气是评价茶叶品质优劣的最重要因子之一,探明茶叶香气的化学组成可进一步丰富茶叶香气化学理论,为改善和提高茶叶香气品质提供重要的科学理论依据。【方法】采用全二维气相色谱-飞行时间质谱联用技术(GC×GC-TOFMS)与气相色谱-质谱联用技术(GC-MS)分析西湖龙井茶的香气成分,比较两种分析技术在分离性能上的差异性;结合质谱数据库匹配、化合物保留时间、结构谱图及峰面积等对通过GC×GC-TOFMS分离得到的香气成分进行定性及相对定量分析;进而结合相对高含量化合物(≥0.5%)的气味特征分析西湖龙井茶的特征性香气成分。【结果】通过与GC-MS的总离子流图及色谱峰对比,GC×GC-TOFMS在分离性能上显示出了强大的优越性;定性分析及相对定量分析表明,采用GC×GC-TOFMS技术鉴定出西湖龙井茶样品中存在的522种共性香气成分,归为烯醇、烯、胺、烷烃、醛、烯醛、醚、醇、酯、内酯、烯酯、烯酮、酮、酚、酸、含硫化合物、氮杂环化合物、氧杂环化合物、芳香烃及炔等20类化合物,其中芳香烃的数量最多(77个),烷烃(50个)、烯(43个)、酯(43个)、酮(41个)次之,炔类最少(3个);戊烯-3-醇、顺-3-己烯醇、芳樟醇、α-松油醇、香叶醇、丁烷、甲基环戊烷、2,2,4,6,6-五甲基庚烷、十二烷、二十一烷、二十四烷、三十一烷、乙醛、戊醛、己醛、糠醛、庚醛、苯乙醛、壬醛、乙丙醚、2-乙氧基丁烷、乙基丁基醚、1,2-二乙氧基乙烷、戊基乙基醚、正戊醇、叔丁醇、苄醇、苯乙醇、植醇、邻苯二甲酸二异丁酯、酞酸二丁酯、乙基-2-(5-甲基-5-乙烯基四氢呋喃-2-烯)丙基-2-烯碳酸酯、顺-己酸-3-己烯酯、棕榈酸甲酯、乙偶姻、2,4-二叔丁基苯酚、异戊酸、壬酸、棕榈酸、亚油酸、硬脂酸、二甲基亚砜、苯并噻唑、吲哚、咖啡碱、芳樟醇氧化物(吡喃型)、2,3-二氢苯并呋喃、乙苯、丙苯及1-甲基萘这50种挥发性化合物的含量较高(≥0.5%),对西湖龙井茶的香气品质具有重要影响。特征性香气成分分析表明,具有愉悦气味特征的烯醇、醛、醇、酯及芳香烃等化合物是西湖龙井茶优异香气品质的主要化学物质基础,而无特殊气味或散发难闻气息的烷烃、醚类、酸类、硫化物以及部分低阈值的香气化合物对西湖龙井茶香气品质的贡献程度也具有一定的研究价值。【结论】该技术在茶叶香气成分分析上的成功应用,可以弥补一维气相色谱分析上的缺陷,使可分析的香气化合物数量提高5倍以上,为后续深入研究茶叶香气成分的化学组成以及揭示茶叶香气品质的形成机理提供先进的技术支撑。

关键词: 西湖龙井, 香气成分, 香气特征, 全二维气相色谱-飞行时间质谱技术

Abstract: Aroma is one of the most important factors affecting the quality of tea, and identifying the chemical composition of tea aroma will enrich the basic theory of aroma chemistry of tea and establish an important theoretic ground to improve and enhance the aroma quality of tea. 【Method】 Aroma components of Xihu Longjing tea were analyzed by using a comprehensive two- dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) and gas chromatography-mass spectrometry (GC-MS), and the separating capacities of GC×GC-TOFMS and GC-MS were compared. Then, the qualitative and relative quantitative analyses of aroma components separated by GC×GC-TOFMS were carried out according to the standard mass spectra in available databases, retention time, structured chromatograms and peak areas. Furthermore, the characteristic aroma compositions of Xihu Longjing tea were discussed according to the odor characteristics of its compounds with relatively high contents (≥0.5%). 【Result】 GC×GC-TOFMS technique displayed the strong superiority on the separating capacity by comparing the total ion chromatograms and chromatographic peaks with GC-MS. A total of 522 common volatile components were identified with a good match, and then further classified into 20 types of compounds, such as enols, alkenes, amines, alkanes, aldehydes, olefin aldehydes, ethers, alcohols, esters, lactones, allyl esters, ketenes, ketones, phenols, organic acids, sulphur compounds, nitrogen heterocyclic compounds, oxygen heterocyclic compounds, aromatic hydrocarbons, and alkynes; and the largest numbers of aromatic hydrocarbons (77), large numbers of alkanes (50), alkenes (43), esters (43) and ketones (41), and the minimum numbers of alkynes (3) were included. Relative quantitative analysis showed that 50 volatile components, including 1-penten-3-ol, cis-hex-3-en-1-ol, linalool, α-terpineol, geraniol, butane, methylcyclopentane, 2,2,4,6,6-pentamethylheptane, dodecane, heneicosane, tetracosane, hentriacontane, acetaldehyde, pentanal, hexanal, furfural, heptanal, phenylacetaldehyde, nonanal, 1-ethoxypropane, 2-ethoxybutane, 1-ethoxybutane, 1,1-diethoxyethane, 1-ethoxypentane, pentanol, tert-butanol, benzyl alcohol, phenethyl alcohol, phytol, diisobutyl phthalate, dibutyl phthalate, ethyl 2-(5-methyl-5-vinyltetrahydrofuran-2-yl) propan-2-yl carbonate, (Z)-hex-3-en-1-yl hexanoate, methyl palmitate, acetoin, 2,4-di-tert-butylphenol, 3-methylbutanoic acid, nonanoic acid, hexadecanoic acid, linoleic acid, octadecanoic acid, dimethyl sulfoxide, benzothiazole, indole, caffeine, linalool oxide (pyranoid), 2,3-dihydrobenzofuran, ethylbenzene, phenylpropane, and 1-methylnaphthalene, were found to be relatively high contents in aroma components of Xihu Longjing tea, suggesting that they played an important role in effecting the aroma quality of Xihu Longjing tea. The analysis of characteristic aroma compositions indicated that enols, aldehydes, alcohols, esters and aromatic hydrocarbons with agreeable smell would be responsible for the outstanding aroma quality of Xihu Longjing tea, and the effects of alkanes, ethers, organic acids and sulphur compounds with no special smell or offensive odor and aroma compounds with low odor threshold values were also worth future research. 【Conclusion】 The successful application of GC×GC-TOFMS technology in tea aroma analysis has improved the number of identified compounds significantly, which could make up for the defects of GC-MS analysis to some extent and supply the advanced technical support for the future in-depth studies on the chemical composition of tea aroma and formation mechanism of tea aroma quality.

Key words: Xihu Longjing Tea, aroma components, aroma characteristic, GC×GC-TOFMS