Comparative analysis of volatiles difference of Yunnan sun-dried Pu-erh green tea from different tea mountains: Jingmai and Wuliang mountain by chemical fingerprint similarity combined with principal component analysis and cluster analysis.

Xuemei Gao,Jiangbing Li,Chen Wang,Shidong Lv,Yuanshuang Wu,Qingxiong Meng

doi:10.1186/s13065-016-0159-y

Xuemei Gao, Jiangbing Li

Open Access

https://doi.org/10.1186/s13065-016-0159-y

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Abstract

BackgroundModern instrumental analysis technology can provide various chemical data and information on tea samples. Unfortunately, it remains difficult to extract the useful information. We describe the use of chemical fingerprint similarities, combined with principal component and cluster analyses, to distinguish and recognize Pu-erh green teas, which from two tea mountains, Wuliang and Jingmai, in the Pu-erh district of Yunnan province. The volatile components of all 20 Pu-erh green teas (10 Wuliang and 10 Jingmai teas) were extracted and identified by headspace solid-phase micro extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS).ResultsSixty-three volatiles (including alcohols, hydrocarbons, ketones, and aldehydes) were identified in the 20 Pu-erh green teas, and differences in compound compositions between them were also observed. Through fingerprint similarity, combined with principal component and cluster analyses, the 20 Pu-erh green teas were differentiated successfully based on their volatile characteristics.ConclusionsThis study demonstrates that the GC-MS combined with chemical fingerprint and unsupervised pattern recognition method is suitable for the investigation of the volatile profiling and evaluating the quality and authenticity of teas related to the different origins.Graphical abstractDifferentiate Pu-erh green teas from different tea mountains by using chemical fingerprint similarity and multivariate statistical methodsElectronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0159-y) contains supplementary material, which is available to authorized users.

Highlights

Modern instrumental analysis technology can provide various chemical data and information on tea samples
Sixty-eight chromatographic peaks were recognized in the sun-dried Pu-erh green teas and 63 peaks were identified using NIST 08.L MS library and retention indices (RIs)
The common peaks were confirmed by relative standard deviation (RSD %) values having relative retention time values of less than 1 %

Summary

Introduction

Modern instrumental analysis technology can provide various chemical data and information on tea samples. We describe the use of chemical fingerprint similarities, combined with principal component and cluster analyses, to distinguish and recognize Pu-erh green teas, which from two tea mountains, Wuliang and Jingmai, in the Pu-erh district of Yunnan province. The volatile components of all 20 Pu-erh green teas (10 Wuliang and 10 Jingmai teas) were extracted and identified by headspace solid-phase micro extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). Pu-erh tea has been produced from the big-leaf species of tea trees in China’s Yunnan province for 1700 years [1]. Yunnan’s forests and smallholder agro-ecosystems result in a diversity of teas, including dozens of wild relatives and hundreds of cultivars and local varieties [4]. Forest (mountain) tea generally includes tea trees that are wild, were sparsely planted in forests, or were cultivated and have become feral. The forest tea is relatively more expensive than tableland tea owing to its low yield and difficulty in harvesting

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