Discrimination of green tea quality using the electronic nose technique and the human panel test, comparison of linear and nonlinear classification tools

In this work, the capacity of an electronic nose (E-nose, PEN2) to classify tea quality grades is investigated. Three tea groups with different quality grades were harvested at different times. Principal component analysis (PCA) and artificial neural network (ANN) were applied to identify the different tea samples. PCA provided perfect classification of tea quality grades. In the analysis of age, six groups of XinyangMaojian green tea were distinguished completely by PCA. The results of ANN analysis gave a high percentage of correct discrimination of green tea samples. The correct identification rates of the training and testing data were 98.6% and 83%, respectively, for three grades of green tea samples harvested in 2009. The correct identification rates of the training and testing data were 100% and 87.8%, respectively, for three grades of green tea samples harvested in 2010. In the analysis of age, the correct discrimination percentages for six groups of XinyangMaojian green tea were 99.4% and 88.9% for training and testing data, respectively. These results indicate that the electronic nose could be successfully used for the detection of teas of different quality grades and ages.

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Aroma dynamic characteristics during the drying process of green tea by gas phase electronic nose and gas chromatography-ion mobility spectrometry

LWT ◽

10.1016/j.lwt.2021.112691 ◽

2021 ◽

pp. 112691

Author(s):

Yanqin Yang ◽

Jiayu Chen ◽

Yongwen Jiang ◽

Michael C. Qian ◽

Yuliang Deng ◽

...

Keyword(s):

Gas Chromatography ◽

Gas Phase ◽

Green Tea ◽

Electronic Nose ◽

Ion Mobility Spectrometry ◽

Dynamic Characteristics ◽

Ion Mobility ◽

Drying Process

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Effects of steaming conditions on tea quality in the manufacturing of green tea (Sencha).

Chagyo Kenkyu Hokoku (Tea Research Journal) ◽

10.5979/cha.1987.73 ◽

1987 ◽

pp. 73-80 ◽

Cited By ~ 1

Author(s):

Kaoru OHMORI ◽

Shinichiro NAKAMURA ◽

Toshiro WATANABE ◽

Kazuya KATSUKI

Keyword(s):

Green Tea ◽

Tea Quality

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Characterization of the effect of cis-3-hexen-1-ol on green tea aroma

Scientific Reports ◽

10.1038/s41598-020-72495-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Cong-ning Nie ◽

Yuan Gao ◽

Xiao Du ◽

Jin-lin Bian ◽

Hui Li ◽

...

Keyword(s):

Green Tea ◽

Electronic Nose ◽

Chemometric Analysis ◽

Differential Threshold ◽

Value Evaluation ◽

Odor Activity Value ◽

Aroma Components ◽

Green Odor

Abstract cis-3-Hexen-1-ol has been regarded as the main source of green aroma (or green odor) in green tea. However, no clear findings on the composition of green aroma components in tea and the effect of cis-3-hexen-1-ol on other aroma components have been reported. In this study, the main green aroma components in green tea were characterized, especially the role of cis-3-hexen-1-ol in green aroma was analyzed and how it affected other aroma components in green tea was studied. Based on the GC–MS detection, odor activity value evaluation, and monomer sniffing, 12 green components were identified. Through the chemometric analysis, cis-3-hexen-1-ol was proven as the most influential component of green aroma. Moreover, through the electronic nose analysis of different concentrations of cis-3-hexen-1-ol with 25 other aroma components in green tea, we showed that the effect of cis-3-hexen-1-ol plays a profound effect on the overall aroma based on the experiments of reconstitution solution and natural tea samples. GC–MS and CG-FID confirmed that the concentration range of the differential threshold of green odor and green aroma of cis-3-hexen-1-ol was 0.04–0.52 mg kg−1.

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