Abstract
As one of the six major teas in China, dark tea is mainly produced in Yunnan, Hunan, Sichuan, Hubei and Guangxi provinces of china. At present, identification geographical of teas mainly depends on the sensory evaluation, because of lacking the quantitative discriminate method. In this study, 38 dark teas were taken, which were collected from five regions. And the main chemical compositions of tea samples were detected according to international standard. Using SPSS18.0 statistical software to reduction dimension, then chose four compositions (GA, EGC, caffeine, total catechins) as the principal component factors, by using Bayes discriminate analysis method, we established the quantitative discriminate model, which could identify the dark teas from different regions. The results show that the Bayes discriminate analysis can be used to discriminate the 38 samples from five regions and the correct rate could be reached 100%, which means the methods established is reliable.
Highlights
Dark tea is one of the six major teas in China, which initial processes are fixing, rolling, piling and drying
Different concentrations of theanine were prepared by ISO, Fig. 1: High-Performance Liquid Chromatography (HPLC) chromatogram of mixed references of catechins, caffeine and theanine 151
Results of discriminate analysis: Four principal components had been extracted by principal components analysis and the discriminate functions from the extracted chemical factors were established as the following equations: Yunnan = 24.577 *Total catechins+78.093* Caffeine-50.554 *EGC-2.021 *Gallic Acid (GA)-143.132 Hunan = 58.963 *Total catechins+63.896 *Caffeine-88.161 *EGC-26.121 *GA-135.104 Guangxi = 22.424 *Total catechins+71.360* Caffeine-34.355 *EGC-9.321 *GA-123.236 Hubei = 17.311 *Totalcatechins+28.298* Caffeine-23.861 *EGC-7.098*GA-23.287 Sichuan = 13.237 *Total catechins+35.205* Caffeine-24.862 *EGC-0.683 *GA-30.827
Summary
Dark tea is one of the six major teas in China, which initial processes are fixing, rolling, piling and drying. Fourier Transform Infrared Spectroscopy (FTIR) has been used to identify different regions of dark teas. 5 typical dark tea samples were analyzed by Fourier Transforms Infrared Spectroscopy (FTIR) and their spectral characteristics were compared (Xin-He et al, 2012).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
