scholarly journals Green Tea Quality Evaluation Based on Its Catechins and Metals Composition in Combination with Chemometric Analysis

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1689 ◽  
Author(s):  
Wojciech Koch ◽  
Wirginia Kukula-Koch ◽  
Łukasz Komsta ◽  
Zbigniew Marzec ◽  
Wojciech Szwerc ◽  
...  
Keyword(s):  
Green Tea ◽  
Quality Evaluation ◽  
Chemometric Analysis ◽  
Tea Quality

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

1987 ◽  
pp. 73-80 ◽  
Author(s):  
Kaoru OHMORI ◽  
Shinichiro NAKAMURA ◽  
Toshiro WATANABE ◽  
Kazuya KATSUKI
Keyword(s):  
Green Tea ◽  
Tea Quality

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

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.

scholarly journals Chlorophyll as an indicator of green tea quality

2014 ◽  
Vol 83 (10) ◽  
pp. S103-S109 ◽  
Author(s):  
Martina Ošťádalová ◽  
Bohuslava Tremlová ◽  
Jana Pokorná ◽  
Martin Král
Keyword(s):  
Chlorophyll Content ◽  
Green Tea ◽  
Storage Time ◽  
Chlorophyll Concentration ◽  
Storage Period ◽  
Storage Conditions ◽  
Qualitative Variable ◽  
Chlorophyll Contents ◽  
Tea Quality ◽  
The Relationship

The objective of this work was to study the changes in chlorophyll contents in green teas stored under different conditions and to suggest the most suitable way and length of green tea storage. A secondary aim was to evaluate the possibility of using the chlorophyll content as an indicator of tea freshness. Samples for analysis were obtained from a range of tea-growing regions. Chlorophyll contents were measured using UV-vis spectrophotometry. Chlorophyll absorbance was measured at 642.5 and 660 nm. Prior to storage, chlorophyll concentration in teas ranged from 1.12 to 1.89 mg per 1 g of tea, which corresponded to data given by other authors. Storage was found to lead to a decline in chlorophyll concentration. From the 6th month of storage onwards, a significant decrease (P < 0.05) was observed in all samples, irrespective of storage conditions. Based on the findings of this study, original and metal packaging can be considered the most chlorophyll-friendly. On the other hand, glass and paper packaging stored in direct daylight were found to have the strongest impact on chlorophyll concentration. Overall, it can be concluded that the storage time can have a strong influence on oolong green tea colour as an important qualitative variable. Thus, the shelf-life of tea should be shorter than the 12 months claimed by most manufacturers. Once the relationship between changes in chlorophyll concentration and length of the storage period had been established, the chlorophyll content was suggested as an indicator of the storage time (freshness) of a tea substance.

Intelligent evaluation of storage period of green tea based on VNIR hyperspectral imaging combined with chemometric analysis

2020 ◽  
Vol 110 ◽  
pp. 103450 ◽  
Author(s):  
Luqing Li ◽  
Jing Huang ◽  
Yujie Wang ◽  
Shanshan Jin ◽  
Menghui Li ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Green Tea ◽  
Storage Period ◽  
Chemometric Analysis

Effect of selenium spraying on green tea quality

2001 ◽  
Vol 81 (14) ◽  
pp. 1387-1390 ◽  
Author(s):  
Qiuhui Hu ◽  
Jaun Xu ◽  
Genxing Pan
Keyword(s):  
Green Tea ◽  
Tea Quality

scholarly journals Differential Contribution of Jasmine Floral Volatiles to the Aroma of Scented Green Tea

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jian-Xia Shen ◽  
Mohammad M. Rana ◽  
Guo-Feng Liu ◽  
Tie-Jun Ling ◽  
Margaret Y. Gruber ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Green Tea ◽  
Manufacturing Processes ◽  
Floral Volatiles ◽  
Methyl Anthranilate ◽  
Tea Quality ◽  
Potent Odorants ◽  
Floral Volatile ◽  
Jasminum Sambac ◽  
Differential Contribution

Tea volatiles’ generation and retention over manufacturing processes are crucial for tea quality. In this study, floral volatile adsorption and retention in green tea scented with Jasminum sambac flowers were examined over the scenting process. Out of 34 enhanced volatiles in the scented tea, β-ionone, β-linalool, indole, and methyl anthranilate were the most potent odorants with 5.1–45.2-fold higher odor activity values than the corresponding controls in the nonscented tea. Scenting efficiencies for the floral volatiles retained in the scented tea (the percentage of volatile abundance over its corresponding amount in jasmine flowers) ranged from 0.22% for α-farnesene to 75.5% for β-myrcene. Moreover, due to additional rounds of heat treatment for scented green tea manufacturing, some volatiles such as carotenoid-derived geraniol and β-ionone and lipid-derived (Z)-jasmone were heat-enhanced and others such as nonanal were heat-desorbed in the scented green tea. Our study revealed that dynamic volatile absorption and desorption collectively determined tea volatile retention and tea aroma. Our findings may have a great potential for practical improvement of tea aroma.

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