蒙山名茶蒙顶甘露和蒙山毛峰特征香气成分的GC-MS测定与分析

Analysis of characteristic aroma components in famous Mengshan teas Mengding Ganlu and Mengshan Maofeng by GC-MS

采用同时蒸馏萃取法和气相色谱质谱（gas chromatography-mass spectrometry ， GC-MS）分析方法系统分析了蒙山茶原产地保护区域内蒙泉、后盐、陇西3个产地及保护区外合江产地蒙顶甘露和蒙山毛峰香气成分的特征与差异.结果表明，在鉴定的63种香气成分中，醇类和醛类占一半以上（59.16％～71.42％）.在蒙顶甘露和蒙山毛峰的香气组分中均以植醇、香叶醇、L-芳樟醇、壬醛和正庚醛这5个成分所占比例较高；保护区内蒙顶甘露和蒙山毛峰最重要的香气特征是植醇和壬醛含量显著高于保护区外，其总量分别占保护区中心内甘露的29.95％和毛峰的40％、保护区外甘露的0％和毛峰的11.27％，同时也是区别于其他名优绿茶的最主要的香气成分.由保护区中心向外延伸，蒙顶甘露和蒙山毛峰的香型有相似的变化规律：由保护区中心的板栗香型经中间的铃兰类鲜爽花香型逐渐过渡至边沿的蜜糖香、花香型.总体上，原产地保护区域内蒙顶甘露和蒙山毛峰的香气品质优于其他非原产地保护区域的蒙顶甘露和蒙山毛峰.

Mengding Ganlu produced in Mengshan Mountain of Sichuan Province has been one of the most famous teas and tribute teas in history . Like Mengding Ganlu , Mengshan Maofeng is high-quality green tea produced in Mengshan Mountain area . The processing techniques of these two kinds of tea are typical of green tea processing . Historically , these two kinds of tea were produced in Mengquan , Houyan and Longxi villages of Mengshan Mountain , Mingshan County . With the increasing demands of Mengding Ganlu and Mengshan Maofeng , the teas similar to Mengding Ganlu and Mengshan Maofeng produced throughout Ya＆#39;an City area are sold as Mengding Ganlu and Mengshan Maofeng nowadays , which infringes the protection of origin place of Mengding Ganlu and Mengshan Maofeng . It is necessary to develop an instrumental technique to identify the authenticity of these two kinds of tea so as to protect consumer rights . Owing to the differences in tea cultivars , environmental conditions and processing methods , chemical compositions of tea show area specific characteristics , among which volatile aroma components are important indicators . The studies on geo-aroma characteristics and brand protection of famous teas such as Westlake Longjing tea , Dongting Biluochun tea and Yunnan Pu-erh tea were reported . However , the study concerning Mengshan teas has not been available so far . The purpose of the present study was set to develop a method to discriminate the volatile aroma compounds of authentic Mengding Ganlu and Mengshan Maofeng produced in the three protected villages including Mengquan , Houyan and Longxi from those produced outside the three protected villages or non-protected areas such as Hejiang . Tea volatile aroma components were collected by simultaneous distillation and extraction （ SDE） method using 30 .00 g dry tea and 400 mL distilled water , with ethyl decanoate as internal standard ,exacted at 45 ℃ for 1 h . The extracted volatile aroma components were identified by gas chromatography-mass spectrometry （GC-MS） , based on the spectral library search （ NIST147 , NIST27 and WILEY7） and published references . The GC-MS data of the relative contents of aroma components were expressed as the ratio of the peak area to internal standard （ ethyl decanoate） . The tested results showed that there were 64 peaks detected , among which 63 were identified . The main volatile components of Mengding Ganlu and Mengshan Maofeng were alcohols and aldehydes , which accounted for 59 .16% 71 .42% of the identified compounds .Furthermore , Mengding Ganlu and Mengshan Maofeng had high concentrations of phytol , geraniol , L-linalool , nonanal and n-heptaldehyde , which could be used to discriminate from famous green teas produced outside the Mengshan Mountains such as Westlake Longjing tea and Dongting Biluochun tea . Mengding Ganlu and Mengshan Maofeng produced in the protected areas had higher concentrations of phytol and nonanal than those from the non-protected areas . These were considered to be related to the unique natural climatic conditions of Mengshan Mountain and their special processing techniques . Phytol and nonanal had floral and fruity flavor . According to the quantitative evaluation of aroma components and tea aroma classification , the aroma types of Mengding Ganlu and Mengshan Maofeng produced in the central zone of the protected areas showed chestnut flavor , the teas produced in the edge areas showed honey and floral flavor , with fresh lily flower scent in the betw een . It is concluded from this study that Mengding Ganlu and Mengshan Maofeng produced in the protected place of origin have higher concentrations of phytol and nonanal than those from non-protected areas and they can be used to identify the authenticity of Mengding Ganlu and Mengshan Maofeng .