Liupao tea belongs to the black tea of the six major tea categories, native to Liubao Township, Cangwu County, Wuzhou City, Guangxi, and is known for its "red, strong, chen and alcohol".
High-quality Liupao tea, the appearance of black brown, soup color red thick and bright, mellow taste back sweet, aroma mellow, vintage high-quality Liupao tea will also have a subtle betel nut aroma.
The unique quality of Liupao tea is inseparable from its processing technology, when the wo dui fermentation, the humid and hot environment, as well as the role of microorganisms and enzymes, is the change of the contents of Liupao tea, forming its unique quality.
In everyone's cognition, Liupao tea has the characteristics of aging as much as possible. So what is the difference between the taste and endoplasm of Liupao tea in different years?
Wei Liuhua of Guangxi Guilin Tea Science Institute took the 2004, 2007 and 2010 Liupao tea produced by the same manufacturer as the research object, conducted sensory evaluation and content determination of them, and unveiled the difference between Liupao tea in different years.
Through sensory evaluation, it was found that with the prolongation of the storage time, the tea soup changed from slightly turbid to bright, the soup color changed from yellow to red to deep red and then to red and transparent, the aroma became more and more obvious, the taste was more mellow and smooth, and the leaf bottom changed from yellow brown to reddish brown and then to black brown oil.
This sensory evaluation result is basically consistent with Liang Yanni's sensory evaluation of Liupao tea of different years.
So, what are the relationships between the sensory characteristics of Liupao tea and the substances contained therein? How have they changed during storage?
It can be seen from the table that with the prolongation of storage time, tea polyphenols show a decreasing trend. This is due to the fact that in the storage process, the tea polyphenols have hydrolysis, oxidation, degradation and other effects, because the content is gradually reduced, and the reduction of the content of tea polyphenols, so that the astringency of the tea is less obvious, the better the overall alcohol.
The free amino acid content in Liupao tea is low, and with the increase of storage time, free amino acids have also undergone oxidative degradation, from 1.4% in 2010 to 1.2% in 2004.
On the contrary, caffeine, with the increase of the year, not only did not decrease, but the content is getting higher and higher, the caffeine content in Liupao tea in 2010 was 2.9, and the increase in 2007 and 2004 was 10% and 37% respectively.
Caffeine has the effect of eliminating fatigue, refreshing and other effects, and is mainly bitter. However, during fermentation, it will produce a polymer with the polyphenols in the tea, masking the bitter taste of caffeine.
Theaflavins, thearubicin, theaflavins have an important impact on the color of tea soup, leaf bottom, etc., with the extension of the year, the theaflavin content in Liupao tea is relatively stable, the thearubicin decreases year by year, and theaflamin shows an upward trend, so the color of tea soup deepens year by year.
In terms of the content of water leaching, the research results of Wei Liuhua et al. and Liang Yanni et al. were different. The results of the former determination showed that the content of water leachate gradually decreased with the year, while the results of the latter study showed that the content of water leachate increased with the increase of the year.
In terms of aroma, with the increase of storage years, there are also some changes in aroma composition, of which the 2004 Liupao tea is the most obvious, but these teas do not appear betel nut fragrance.
Overall, there are certain differences in the content and aroma composition of Liupao tea in different years, with the increase of storage years, the water vapor and green odor in Liupao tea soup are getting lighter and lighter, and the chen aroma is becoming more and more obvious, and the taste is becoming more and more mellow.
Resources:
1. "Study on the Quality Change of Liupao Tea at Different Storage Times", Wei Liuhua et al., Southwest Journal of Agricultural Sciences, Vol. 28, No. 1, 2015;
2. "Research on the Quality Change of Liupao Tea in Different Years", Liang Yanni et al., Shaanxi Agricultural Science, 2016, (04): 60~63.