Metabolite Profiling Using ¹H NMR Spectroscopy for Quality Assessment of Green Tea, Camellia sinensis (L.)

Abstract

A set of 191 green teas from different countries was collected and analyzed by (1)H NMR. It was proposed to establish if the teas could be discriminated according to the country of origin or with respect to quality. Both principal component analysis (PCA) and cluster analysis were applied to the data. Some separation of Chinese and non-Chinese teas was observed. The present results did not allow allocation of samples to individual countries, but cluster analysis suggested that it might be possible with an augmented sample set. The PCA did show a separation between the Longjing type (highest quality Chinese tea) and most other Chinese teas and indicated some metabolites that could be responsible for the difference. Longjing teas showed higher levels of theanine, gallic acid, caffeine, epigallocatechin gallate, and epicatechin gallate and lower levels of epigallocatechin when compared with other teas. These compounds have been mentioned previously in connection with quality, but it was also shown that higher levels of theogallin (5-galloyl quinic acid), theobromine, 2-O-(beta-l-arabinopyranosyl)-myo-inositol and some minor sugar-containing compounds were found in Longjing teas while higher levels of fatty acids and sucrose were found in the other teas. These new markers could prove to be useful for the authentication of bulk tea.

Comparison of Phenolic Compounds and Taste of Chinese Black Tea

“…Multivariate analysis on chemical components provides useful methodology to distinguish the origin, quality and category of teas (Liang et al, 2003(Liang et al, , 2007Le Gall et al, 2004;Wang et al, 2010).…”

Combining Genomics and Metabolomics for the Discovery of Regulatory Genes and Their Use in Metabolic Engineering to Produce 'Healthy Foods'

“…Internal (chemical) references and electronic references (ERETIC method) are used for quantitative, instrument-related intensity corrections. 2D NMR experiments (COSY, TOCSY, J-resolved, 1 H/ 13 C correlations) are carried out at 600 MHz to extend assignments of Arabidopsis metabolites already made at 400 MHz (Le Gall et al, 2004) and a library of 600 MHz reference spectra is being compiled from standards and compounds isolated by LC/SPE.…”

“…We previously analysed Arabidopsis leaf material by LC/UV/DAD with a method that can measure four of the major groups of Arabidopsis metabolites in a single run (Le Gall et al, 2004). The LC gradient is a multipurpose chromatographic method that detects glucosinolates at 227 nm, sinapate esters at 325 nm, flavonols at 370 nm and anthocyanins at 520 nm on a C18 5 μm reversed-phase silica column.…”

Multivariate Analysis for 1H-NMR Spectra of Two Hundred Kinds of Tea in the World

“…2,3 We studied urinalysis using 1 H-NMR spectra of disease model rats to detect basic metabolisms, which resulted in clear classifications. 4 For quality assessment or authentication, a metabolite profiling or some chemometric analysis using 13 C or 1 H NMR spectroscopy was carried out for several kinds of tea, 5 coffee, 6 juice, 7 beer, 8 olive oil, 9 crude oil, 10 and other mixtures. 11 The components of some of the kinds of teas were analyzed using mass spectroscopy, 12 HPLC 13 or 1 H NMR spectroscopy.…”

“…11 The components of some of the kinds of teas were analyzed using mass spectroscopy, 12 HPLC 13 or 1 H NMR spectroscopy. 5 Gall et al researched the metabolite profiling of 191 kinds of green teas, mainly Chinese tea, using 1 H NMR spectroscopy. 5 They discussed in detail the chemical compounds of the teas and carried out of PCA and a cluster analysis in connection with quality assessment and authentication.…”