Discrimination of six tea categories coming from different origins depending on polyphenols, caffeine, and theanine combined with different discriminant analysis

Ning, Jingming; Cao, Qian; Su, Huan; Zhu, Xiaofeng; Wang, Kai; Wan, Xiaochun; Zhang, Zhengzhu

doi:10.1080/10942912.2017.1354880

Cited by 13 publications

(15 citation statements)

References 23 publications

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“…Quantification was conducted by the calibration curves of five external standards including four theaflavins and caffeine (Table S2). The concentration of total catechins and theaflavins was calculated using the following equations:

\begin{matrix} Total catechins (() %) & = ((), % (() +) ‐ catechin) + \\ ((), % (() -) ‐ epigallocatechin gallate) + \\ ((), % (() -) ‐ epicatechin) + \\ ((), % (() -) ‐ epicatechin gallate) \end{matrix}

\begin{matrix} Total theaflavins (() %) & = ((), % Theaflavin) + \\ ((), % Theaflavin ‐ 3 ‐ gallate) + \\ ((), % theaflavin ‐ 3^{'} ‐ gallate) + \\ ((), % theaflavin ‐ 3, 3^{'} ‐ normaldi ‐ gallate) \end{matrix}

…”

Section: Methodsmentioning

confidence: 99%

“…The determination of theanine content was slightly modified from an early report . Theanine was analyzed by the HPLC system described above, and the separation was performed on a 250 × 4.6 mm, 4 μm Phenomenex Synergi Hydro‐RP C18 column (Phenomenex, Torrance, CA, USA).…”

Section: Methodsmentioning

confidence: 99%

“…Quantification was conducted by the calibration curves wileyonlinelibrary.com/jsfa of five external standards including four theaflavins and caffeine (Table S2). The concentration of total catechins and theaflavins was calculated using the following equations: 21 Total catechins (%) = (%(+)-catechin)+…”

Section: The Determination Of Tea Phenolic Compounds Caffeine and Thmentioning

confidence: 99%

“…The determination of theanine by HPLC The determination of theanine content was slightly modified from an early report. 21 Theanine was analyzed by the HPLC system described above, and the separation was performed on a 250 (Table S2). The calibration curve was drawn by plotting the peak areas as a function of the theanine concentration that was used.…”

Section: The Determination Of Tea Phenolic Compounds Caffeine and Thmentioning

confidence: 99%

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Geographical origin traceability of Keemun black tea based on its non‐volatile composition combined with chemometrics

et al. 2019

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BACKGROUND Non‐volatile compounds play a key role in the quality and price of Keemun black tea (KBT). The non‐volatile compounds in KBT samples from different producing areas normally vary greatly. The development of rapid methods for tracing the geographical origin of KBT is useful. In this study, we develop models for the discrimination of KBT's geographical origin based on non‐volatile compounds. RESULTS Seventy‐two KBT samples were collected from five towns in Anhui province to determine 13 KBT compounds by high‐performance liquid chromatography (HPLC). Analysis of variance showed that the content of 13 compounds in KBT indicated significant differences (P < 0.05) among five towns. Three multivariate statistical models including principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), and linear discriminant analysis (LDA) were built to discriminate origin. Principal component analysis effectively extracted three principal components, namely theaflavins, galloylated catechins, and simple catechins. The high sensitivity (64.5%–99.2%) was achieved of SIMCA model. To establish the discriminant functions, six variables (gallic acid, (+)‐catechin, (−)‐epigallocatechin gallate, theaflavin‐3‐gallate, theaflavin‐3,3′‐di‐gallate, and total theaflavins) were chosen from 13 variables, and LDA was applied. This gave a satisfactory overall correct classification rate (94.4%) and cross‐validation rate (88.9%) for KBT samples. CONCLUSION The results showed that HPLC analysis together with chemometrics is a reliable approach for tracing KBT and guaranteeing its authenticity. © 2019 Society of Chemical Industry

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\begin{matrix} Total catechins (() %) & = ((), % (() +) ‐ catechin) + \\ ((), % (() -) ‐ epigallocatechin gallate) + \\ ((), % (() -) ‐ epicatechin) + \\ ((), % (() -) ‐ epicatechin gallate) \end{matrix}

\begin{matrix} Total theaflavins (() %) & = ((), % Theaflavin) + \\ ((), % Theaflavin ‐ 3 ‐ gallate) + \\ ((), % theaflavin ‐ 3^{'} ‐ gallate) + \\ ((), % theaflavin ‐ 3, 3^{'} ‐ normaldi ‐ gallate) \end{matrix}

…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: The Determination Of Tea Phenolic Compounds Caffeine and Thmentioning

confidence: 99%

Section: The Determination Of Tea Phenolic Compounds Caffeine and Thmentioning

confidence: 99%

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Geographical origin traceability of Keemun black tea based on its non‐volatile composition combined with chemometrics

et al. 2019

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“…Chemical components have been identified using proton nuclear magnetic resonance and near-infrared spectroscopy (Li, Jin, Sun, Ye, & Liu, 2019;Meng et al, 2017), gas chromatography-mass spectrometry (Luo, Chen, Gao, Liu, & Wu, 2017), electronic tongue (Huo et al, 2014), and electronic nose (Chen, Liu, Zhao, & Ouyang, 2013). High-performance liquid chromatography (HPLC) could classify six tea categories (Ning et al, 2017) and green tea from China and Korea (Jang et al, 2008). Combined with discriminate analysis, HPLC has also been applied for authentic origins discrimination of many agricultural products, such as ginger (Yudthavorasit, Wongravee, & Leepipatpiboon, 2014), wine (Rastija & Srečnik, 2009), honey (Hermosıń, Chicón, & Dolores Cabezudo, 2003), and olive oil (Cunha, Amaral, Fernandes, & Oliveira, 2006).…”

mentioning

confidence: 99%

Discriminating geographical origins of green tea based on amino acid, polyphenol, and caffeine content through high‐performance liquid chromatography: Taking Lu’an guapian tea as an example

Wu²,

Wan

et al. 2019

Food Science & Nutrition

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Seventy‐three Lu'an guapian tea (LAGP) samples were collected from 11 growing locations in the city of Lu'an, Anhui Province, China. Through high‐performance liquid chromatography, 18 amino acids, along with gallic acid, caffeine, and five catechins, were quantitatively detected. Hierarchical cluster, correlation and principal component analysis, and a support vector machine were used for geographical discrimination. The findings suggested that the differences in tea quality between the inner and outer mountain regions are related to isoleucine, leucine, phenylalanine, and valine contents, with a correlation coefficient of more than 0.85. Principal component analysis combining with support vector machine was a feasible method. The identification rates for the inner and outer mountains were 97.96% in the training set and 95.83% in the prediction set. Furthermore, the identification rates for the three counties were 91.84% and 95.83% in the training and prediction sets, respectively.

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Metabolic Flux Enhancement and Transcriptomic Analysis Displayed the Changes of Catechins Following Long-Term Pruning in Tea Trees (Camellia sinensis)

Sun

Zhang²,

et al. 2018

J. Agric. Food Chem.

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The tea tree is a perennial woody plant, and pruning is one of the most crucial cultivation measurements for tea plantation management. To date, the relationship between long-term pruning and metabolic flux enhancement in tea trees has not been studied. In this research, 11-year-old pruned tea trees from four different cultivars were randomly selected for transcriptome analysis and characteristic secondary metabolite analysis together with controls. The findings revealed that epigallocatechin gallate (EGCG) accumulation in pruned tea trees was significantly higher than that in unpruned tea trees. SCPL1A expression (encoding a class of serine carboxypeptidase), which has been reported to have a catalytic ability during EGCG biosynthesis, together with LAR, encoding leucoanthocyanidin reductase, was upregulated in the pruned tea trees. Moreover, metabolic flux enhancement and transcriptome analysis revealed low EGCG accumulation in the leaves of unpruned tea trees. Because of the bitter and astringent taste of EGCG, these results provide a certain understanding to the lower bitterness and astringency in teas from "ancient tea trees", growing in the wild with no trimming, than teas produced from pruned plantation trees.

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Discrimination of six tea categories coming from different origins depending on polyphenols, caffeine, and theanine combined with different discriminant analysis

Cited by 13 publications

References 23 publications

Geographical origin traceability of Keemun black tea based on its non‐volatile composition combined with chemometrics

Geographical origin traceability of Keemun black tea based on its non‐volatile composition combined with chemometrics

Discriminating geographical origins of green tea based on amino acid, polyphenol, and caffeine content through high‐performance liquid chromatography: Taking Lu’an guapian tea as an example

Metabolic Flux Enhancement and Transcriptomic Analysis Displayed the Changes of Catechins Following Long-Term Pruning in Tea Trees (Camellia sinensis)

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