芳樟醇是茶叶中含量很高的香气成分之一,具有左旋和右旋两种光学异构体,而这两者有着完全不同的香气品质。本研究利用手性色谱柱,采用顶空固相微萃取-气相色谱法对绿茶和红茶中芳樟醇旋光异构体的比例进行了分析。结果表明,绿茶和红茶中都同时存在3S-(+)-芳樟醇和3R-(-)-芳樟醇两种光学异构体。供试绿茶茶样中3S-(+)-芳樟醇与3R-(-)-芳樟醇相对含量的比值（S/R）介于2.07~14.05,平均比值为5.21。表明供试绿茶样品中芳樟醇以3S-(+)-芳樟醇为主要存在形式。此外,蒸青绿茶、炒青绿茶和烘青绿茶3种不同类型绿茶中芳樟醇的两种旋光异构体的组成比例也存在很大的差异,其中蒸青绿茶中的S/R比值最低（2.72）,烘青绿茶的S/R比值最高（8.05）,炒青绿茶的S/R比值（4.78）介于两者之间。供试红茶茶样中3S-(+)-芳樟醇与3R-(-)-芳樟醇相对含量的比值（S/R）介于0.65~0.82,平均比值为0.74。表明红茶样品中芳樟醇以3R-(-)-芳樟醇为主要存在形式。绿茶和红茶加工过程中3S-(+)-芳樟醇和3R-(-)-芳樟醇相对含量的比例变化研究表明,在绿茶加工过程中,杀青后S/R比值达到最高,为5.78;在红茶加工过程中,发酵2βh后S/R比值达到最高,为1.59。不同茶树品种鲜叶中芳樟醇旋光异构体的S/R比值有很大差异,检测发现有的茶树品种鲜叶中的芳樟醇以3R-(-)-芳樟醇为主,如高芽齐和英红9号等,其余5个茶树品种鲜叶中的芳樟醇则以3S-(+)-芳樟醇为主。
Linalool is one of the most important tea aroma components with high content, and it has two optical isomers, namely 3R-(-)-Linalool and 3S-(+)-Linalool, both show entirely different aroma qualities. In this study, a method using chiral chromatographic column and based on headspace solid-phase micro-extraction (HS-SPME) was developed to analyze 3R-(-)-Linalool and 3S-(+)-Linalool in green tea and black tea samples. Results showed that 3R-(-)-Linalool and 3S-(+)-Linalool isomers were existed in green and black tea. The ratio of the relative content of 3S-(+)-Linalool to that of 3R-(-)-Linalool in green tea ranged from 2.07 to 14.05, with an average ratio of the relative content of 5.21, while, the ratio varied greatly in steamed green tea, roasted green tea and baking green tea. The ratio of the relative content of 3S-(+)-Linalool and 3R-(-)-Linalool were the highest in baking green tea (8.05), with the lowest in steamed green tea (2.72), and 4.78 in roasted green tea. The ratio of the relative content of 3S-(+)-Linalool to that of 3R-(-)-Linalool in black tea ranged from 0.65 to 0.82, with an average ratio of the relative content of 0.74. The ratio of the two optical isomers during the processing of green and black tea was analyzed as well, with the highest found following de-enzyme stage during the processing of green tea and following 2 h fermentation of black tea (5.78 and 1.59 respectively). Fresh leaves of 12 tea cultivars were also analyzed. Moreover, it varied greatly in different tea cultivars.
[1] 宛晓春. 茶叶生物化学[M]. 北京: 中国农业出版社, 2003: 49.
[2] 游小清, 王华夫, 杨亚军. 茶叶中芳樟醇香叶醇及其配糖体的研究进展[J]. 中国茶叶, 1994, 16(6): 5.
[3] 汪厚银, 李志, 张剑, 等. 基于气质联用/气相色谱-嗅觉测定技术的西湖龙井茶特征香气成分分析[J]. 食品科学, 2012, 33(8): 248-251.
[4] 苗爱清, 吕海鹏, 孙世利, 等. 乌龙茶香气的HS-SPME-GC-MS/GC-O研究[J]. 茶叶科学, 2010, 30(增刊1): 583-587.
[5] Lv H P, Zhong Q S, Lin Z, et al. Aroma characterisation of Pu-erh tea using headspace-solid phase microextraction combined with GC/MS and GC-Olfactometry[J]. Food Chemistry, 2012, 130(4): 1074-1081.
[6] Luisa S, Paola D, Ivana B, et al. Headspace-solid phase microextraction coupled to gas chromatography-combustion-isotope ratio mass spectrometer and to enantioselective gas chromatography for strawberry flavoured food quality control[J]. Journal of Chromatography A, 2011, 1218(42): 7481-7486.
[7] Moreno FD, Blanch GP, Flores G, et al. Development of a method based on on-line reversed phase liquid chromatography and gas chromatography coupled by means of an adsorption-desorption interface for the analysis of selected chiral volatile compounds in methyl jasmonate treated strawberries[J]. Journal of Chromatography A, 2010, 1217(7): 1083-1088.
[8] Cecilia C, Carlo B, Chiara C, et al. Fast headspace- enantioselective GC-mass spectrometric-multivariate statistical method for routine authentication of flavoured fruit foods[J]. Food Chemistry, 2012, 132(2): 1071-1079.
[9] Deepa B, Chandan S C, Mahendra R, et al. Variability in essential oil and bioactive chiral monoterpenoid compositions of Indian oregano (Origanum vulgare L.) populations from northwestern Himalaya and their chemotaxonomy[J]. Industrial Crops and Products, 2009, 30(3): 422-426.
[10] Bonnländer B, Cappuccio R, Liverani F S, et al. Analysis of enantiomeric linalool ratio in green and roasted coffee[J]. Flavour and fragrance journal, 2006, 21(4): 637-641.
[11] Ohloff G, Klein E.Die absolute Konfiguration des Linalools durch Verknüpfung mit dem Pinansystem[J]. Tetrahedron, 1962, 18(1): 37-42.
[12] Padrayuttawat A, Yoshizawa T, Tamura H, et al. Optical Isomers and Odor Thresholds of Volatile Constituents in Citrus sudachi[J]. Food Science and Technology International, 1997, 3(4): 402-408.
[13] Carmen B, Gema F, Marta H.Stereodifferentiation of some chiral aroma compounds in wine using solid phase microextraction and multidimensional gas chromatography[J]. Food Chemistry, 2010, 123(3): 846-851.
[14] Bernreuther A, Schreierc P.Multidimensional gas chromatography/mass spectrometry: a powerful tool for the direct chiral evaluation of aroma compounds in plant tissues. II. Linalool in essential oils and fruits[J]. Phytochemical Analysis, 1991, 2(4): 167-170.
[15] Weckerle B, Toth G, Schreier P.Linalool disaccharides as flavour precursors from green coffee beans (Coffea arabica)[J]. European Food Research and Technology, 2003, 216(1): 6-10.
[16] Ma S J, Mizutani M, Hiratake J, et al. Substrate specificity of β-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing[J]. Bioscience, biotechnology, and biochemistry, 2001, 65(12): 2719-2729.
[17] Steinhaus M, Fritsch H T, Schieberle P.Quantitation of (R)-and (S)-linalool in beer using solid phase microextraction (SPME) in combination with a stable isotope dilution assay (SIDA)[J]. Journal of agricultural and food chemistry, 2003, 51(24): 7100-7105.
[18] Kaltner D.Investigations on the formation of hoppy aroma and technological parameters for the production of hop-aromatic beers
(in German) [D]. Muenchen: Technische Universitaet München, 2000.
浙公网安备 33019902000101号 
