title: 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.
abstract: BACKGROUND
  Modern 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).
  
  
  RESULTS
  Sixty-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.
  
  
  CONCLUSIONS
  This 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 methods.
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500 Yunnan People's Republic of China.
authors.forename: Yuanshuang
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Kunming Grain and Oil and Feed Product Quality Inspection Center, Kunming, 650118 Yunnan People's Republic of China.
authors.forename: Shidong
authors.initials: S
authors.lastname: Lv
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500 Yunnan People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500 Yunnan People's Republic of China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Gao
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500 Yunnan People's Republic of China.
authors.forename: Jiangbing
authors.initials: J
authors.lastname: Li
authors.affiliation: Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500 Yunnan People's Republic of China.
authors.forename: Qingxiong
authors.initials: Q
authors.lastname: Meng
keywords: Chemical fingerprint similarity; Cluster analysis; Gas chromatography-mass spectrometry; Principal component analysis; Pu-erh green tea