Study on the effects of rapid aging technology on the aroma quality of white tea using GC–MS combined with chemometrics: In comparison with natural aged and fresh white tea

Qi, Dandan; Miao, Aiqing; Cao, Jianhua; Wang, Wenwen; Wei, Chen; Shi, Pang; He, Xiugu; Ma, Chengying

doi:10.1016/j.foodchem.2018.05.080

Cited by 109 publications

(60 citation statements)

References 31 publications

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“…These four volatile compounds are found in green tea, and existing studies show that cyclopentanone, (Z)-Linalool oxide and (E)-Linalool oxide are negatively correlated with the grade of green tea [16,32]. It also was reported that phenyl ethyl alcohol, α-Terpineol, and geraniol were all derived from jasmine flowers, having floral or sweet odor [3,4,33]. MS,RI Eugenol 0.12 ± 0.00b 0.25 ± 0.04a 0.11 ± 0.02b 0.10 ± 0.03b 0.05 ± 0.02b 0.06 ± 0.02b a-d Means ± SD followed by the same letter, within a row, are not significantly different (p > 0.05); e 1G, 2G, 3G, 4G, 5G, and 6G represent the standard sample for the grade of jasmine tea from high rank to low rank; f MI, method of identification; N.D., peak intensity lower than triple signal-to-noise.…”

Section: Alcoholsmentioning

confidence: 99%

“…Five aldehydes, namely, benzaldehyde, decanal, hexanal, (E, E)-2,4-heptadienal and β-cyclocitral, were detected in all six grades of jasmine tea. Although aldehydes comprised 0.88% of the identified volatile organic compounds (VOC), they still contributed a lot to the aroma performance due to their low odor threshold [33]. Among aldehydes, benzaldehyde, which provided almond, sugar and burnt aroma notes, and decanal which supplied herbal, fatty and citrus aroma notes, were proven to play an essential role in aroma [4,26,27].…”

Section: Aldehydesmentioning

confidence: 99%

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Comparison of Volatiles in Different Jasmine Tea Grade Samples Using Electronic Nose and Automatic Thermal Desorption-Gas Chromatography-Mass Spectrometry Followed by Multivariate Statistical Analysis

Wang

Zhao

Wu³

et al. 2020

Molecules

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Chinese jasmine tea is a type of flower-scented tea, which is produced by mixing green tea with the Jasminum sambac flower repeatedly. Both the total amount and composition of volatiles absorbed from the Jasminum sambac flower are mostly responsible for its sensory quality grade. This study aims to compare volatile organic compound (VOC) differences in authoritative jasmine tea grade samples. Automatic thermal desorption-gas-chromatography-mass spectrometry (ATD-GC-MS) and electronic nose (E-nose), followed by multivariate data analysis is conducted. Consequently, specific VOCs with a positive or negative correlation to the grades are screened out. Partial least squares-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) show a satisfactory discriminant effect on rank. It is intriguing to find that the E-nose is good at distinguishing the grade difference caused by VOC concentrations but is deficient in identifying essential aromas that attribute to the unique characteristics of excellent grade jasmine tea.

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Section: Alcoholsmentioning

confidence: 99%

Section: Aldehydesmentioning

confidence: 99%

Comparison of Volatiles in Different Jasmine Tea Grade Samples Using Electronic Nose and Automatic Thermal Desorption-Gas Chromatography-Mass Spectrometry Followed by Multivariate Statistical Analysis

Wang

Zhao

Wu³

et al. 2020

Molecules

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“…It prompts the transformation of original plant composition of tea under specific temperature, relative humidity, enzymatic catalysis of plant endogenous enzymes, and microbial enzymatic catalysis. Briefly, the processing steps could be mainly described as withering, fixation, rolling, fermentation (black tea), postfermentation (dark tea), drying, or roasting (Qi et al., ).…”

Section: Introductionmentioning

confidence: 99%

Chemistry and Biological Activities of Processed Camellia sinensis Teas: A Comprehensive Review

Liang

Zhou

et al. 2019

Comp Rev Food Sci Food Safe

363

237

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Tea is a typical processed beverage from the fresh leaves of Camellia sinensis [Camellia sinensis (L.) O. Kuntze] or Camellia assamica [Camellia sinensis var. assamica (Mast.) Kitamura] through different manufacturing techniques. The secondary metabolites of fresh tea leaves are mainly flavan‐3‐ols, phenolic acids, purine alkaloids, condensed tannins, hydrolysable tannins, saponins, flavonols, and their glycoside forms. During the processing, tea leaves go through several steps, such as withering, rolling, fermentation, postfermentation, and roasting (drying) to produce different types of tea. After processing, theaflavins, thearubigins, and flavan‐3‐ols derivatives emerge as the newly formed compounds with a corresponding decrease in concentrations of catechins. Each type of tea has its own critical process and presents unique chemical composition and flavor. The components among different teas also cause significant changes in their biological activities both in vitro and in vivo. In the present review, the progress of tea chemistry and the effects of individual unit operation on components were comprehensively described. The health benefits of tea were also reviewed based on the human epidemiological and clinical studies. Although there have been multiple studies about the tea chemistry and biological activities, most of existing results are related to tea polyphenols, especially (‐)‐epigallocatechin gallate. Other compounds, including the novel compounds, as well as isomers of amino acids and catechins, have not been explored in depth.

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“…GC-MS was recently used to analyze jujube [9], ginseng [10], Zhongning Goji [11], and beef [12]. GC-MS has also been applied to tea aroma analysis [13,14]. However, little is known about the difference of aroma compounds among different grades of Nongxinag Tieguanyin tea, as well as the relationship between aroma compounds and tea grades.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, it can extract relevant information and discover patterns in large series of data [16]. The most frequently used chemometric methods, including PCA [17], PLS-DA [13], and HCA [17], have been confirmed to be efficient and rapid methods to highlight differences among tea samples [18][19][20]. PCA is based on the concept of dimensionality reduction to transform multiple indicators into a few comprehensive ones, thereby simplifying the analysis process [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics

2019

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An aroma-based method for distinguishing different grades of Nongxiang Tieguanyin was explored by taking special grade (K110) and 1–4 grades (K101, K102, K103, and K104) of this tea as samples. Tea samples were analyzed by gas chromatography–mass spectrometry (GC-MS) combined with chemometrics. Results showed differences in the types and relative contents of aroma components among different grades of Nongxiang Tieguanyin tea. In the principal component analysis (PCA) scoring plot, except for K102 and K103, tea samples of different grades were distributed in different regions. Components satisfying variable important for the projection (VIP) > 1 and peak areas with significant differences (p < 0.05) among different tea grades were screened. Finally, 18 differential variables were screened out from 143 volatiles. The clustering results of these variables were consistent with those of PCA. K102 and K103 were initially clustered into one group and then clustered with K101, K110, and K104 in turn. The clear PCA separation of these samples and uniform hierarchical cluster analysis (HCA) clustering results suggests that GC-MS coupled with chemometrics analysis is a valid and accurate approach for discriminating different grades of Nongxiang Tieguanyin. The screened differential variables could represent a difference in aroma quality among five grades of Nongxiang Tieguanyin tea. Clear rules between peak area and the grade were also observed in some differential variables. 1-Ethylpyrrole and unknown-32 were positively correlated with grade. 2-Methylfuran, 2-ethylfuran, 2-methylidenecyclopentan-1-ol, mesityl oxide, 2-amylfuran, and D-limonene were negatively correlated with grade. The peak areas of methyl acetate, dimethyl sulfide, 6-methylhept-5-en-2-one, and (Z)-β-ocimene initially decreased but then increased with declining grade. The toluene content was especially high in K104 but only a negligible difference was observed among other grades. This study provides a potential method for differentiating Nongxiang Tieguanyin teas of different grades based on aroma. Unknown samples could be classified by comparison of their spatial distribution with those of known standard samples in PCA or HCA, as well as the peak area differences of differential variables between unknown samples and known standard samples.

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Study on the effects of rapid aging technology on the aroma quality of white tea using GC–MS combined with chemometrics: In comparison with natural aged and fresh white tea

Cited by 109 publications

References 31 publications

Comparison of Volatiles in Different Jasmine Tea Grade Samples Using Electronic Nose and Automatic Thermal Desorption-Gas Chromatography-Mass Spectrometry Followed by Multivariate Statistical Analysis

Comparison of Volatiles in Different Jasmine Tea Grade Samples Using Electronic Nose and Automatic Thermal Desorption-Gas Chromatography-Mass Spectrometry Followed by Multivariate Statistical Analysis

Chemistry and Biological Activities of Processed Camellia sinensis Teas: A Comprehensive Review

Exploration of a Method of Distinguishing Different Nongxiang Tieguanyin Tea Grades Based on Aroma Determined by GC-MS Combined with Chemometrics

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