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Irreversible sediment formation in green tea infusions.
Yong-Quan Xu1, Gen-Sheng Chen, Qiu-Shuang Wang
1Key Laboratory of Machining and Quality Control of Tea and Beverage Plants, Ministry of Agriculture, Tea Research Inst. Chinese Academy of Agricultural Sciences, 9 South Meiling Road, Hangzhou 310008, China. yqx33@126.com
Journal of Food Science
|February 15, 2012
Summary
Irreversible tea sediment (IRS) formation in green tea is influenced by chemical components like gallated catechins and minerals. Higher extraction temperatures increase IRS, impacting tea quality.
Area of Science:
- Food Science
- Analytical Chemistry
- Material Science
Background:
- Tea sediment formation affects green tea quality and consumer acceptance.
- Understanding the chemical basis of tea sediment is crucial for processing optimization.
Purpose of the Study:
- To investigate the formation and chemical composition of irreversible tea sediment (IRS) in green tea infusions.
- To identify key chemical components influencing IRS formation.
- To determine the effect of extraction temperature on IRS levels.
Main Methods:
- Analysis of IRS content in green tea infusions from various cultivars.
- Utilized Principal Component Analysis (PCA) and regression analysis.
- Quantified chemical components including gallated catechins, minerals (Mn, Ca, Na), and caffeine.
Main Results:
- IRS amounts ranged from 0.10 to 1.47 mg/mL across different tea cultivars.
- Gallated catechins, Mn, Ca, caffeine, Na, and (-)-gallocatechin gallate (GCG) were identified as principal components influencing IRS.
- A regression model was developed: IRS (mg/mL) = -4.226 + 0.275 gallated catechins + 79.551 Na + 7.321 Mn + 21.055 Ca + 0.513 caffeine - 0.129 GCG (R2 = 0.697).
- Minerals were significantly different between reversible tea sediment (RTS) and IRS, with large mineral participation in IRS formation.
- IRS formation increased with higher extraction temperatures.
Conclusions:
- The chemical composition of green tea infusions, particularly gallated catechins and minerals, significantly dictates irreversible tea sediment formation.
- Minerals play a substantial role in the precipitation of irreversible tea sediment.
- Optimizing extraction temperature is essential to minimize irreversible tea sediment formation and maintain green tea quality.
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