Tea alkaloids and tea chemistry


One of the intentionally aged teas, Pu-Erh has a loyal following.

Re: Tea alkaloids and tea chemistry

Postby 茶藝-TeaArt08 » Nov 26th, '13, 22:47

Here's the Hojo article I mentioned above in which, at least in this article, theanine content is linked to more intensive application of fertilizers/nitrogen. As is often the case for me with Hojo I find his viewpoints interesting and generally bearing merit, whether I am in full agreement with them or not.:

http://hojotea.com/en/posts-47/
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Re: Tea alkaloids and tea chemistry

Postby JohnsonH » Nov 26th, '13, 23:12

There are very big difference in natural grown tea tree, organic plantation tea and plantation tea.

Natural tea should be the standard of all, since its the original form of natural growing with the natural available substances.

Organic tea can be well grown if fertilizer method is likely in a more greenish way, while the tea did growth healthily. Certain claims that organic plantations tea/vege/fruits are not as nice like the usual normal in terms of out look such as the leaves may be bitten and not as strong or big in size. But THINK another way, isn't a well grown plant should be more strong in terms of everything? Why is it being weak compare to normal plantation method, something wrong that the plant never grown healthily?

Plantation tea is the most common tea around the world, since we are in Pu Erh topic, plantation tea covers up to more than 85% in overall Yunnan, while natural grown stands the minor 15%. Its surviving enquiry is fertilizer and pesticide. Fertilizer to fulfill the basics living, pesticide to protect it from insect harm.

A Healthy grown tea tree should be able to fight or defense against pest as the tannin compounds are widely distributed in many species of plants, where they play a role in protection from predation, and perhaps also as pesticides, and in plant growth regulation.

Natural grown tea acquire this tannin like a healthy natural body immune system, while plantation tea are different in terms of growing method. Here we focus on tea plantation in Yunnan, because Japan and other countries may varies in method.
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Re: Tea alkaloids and tea chemistry

Postby 茶藝-TeaArt08 » Nov 27th, '13, 15:48

shah82 wrote:Theanine is produced more in shade, less in sun.


Shah,

Yes, thank you. My knowledge of the underlying causes for increased theanine content is cursory. I set up a Deepdyve account to have access to the scientific/journal literature on tea. I am amazed (and excited) at how many studies are actually being done. Last night I read a study titled "Determination of amino acids in white, green, black, oolong, pu-erh teas and tea products" by Rouba Horanni and Ulrich H. Engelbracht. The study affirmed your assertion and states that, "Shading of the tea plant was employed to enhance the amount of amino acids, especially that of 1-theanine (Chu and Juneja, 1997)."

In Hojo's account (http://hojotea.com/en/posts-47/) he links to his study but the study is in Japanese. However, Hojo writes, "In 1950, Dr. Sakado discovered the substance called Theanine that produces the taste of umami which taste is somewhat like “mono sodium gluconate”, the so-called “Ajinomoto”, as what most people are familiar with. They also discovered the relationship of when more nitrogen fertilizer was used, the more theanines were accumulated in the tea."

Tying into Hojo's assertion about theanine and umami, the study I read states, "Glutamic acid and theanine are responsible for the umami taste of green tea (Ekborg-Ott et al.,1997; Kaneko et al., 2006)." I do, more or less, trust Hojo and know his background education is in food science (agricultural chemistry with a masters degree in food science). Without a background in the field, I wouldn't know, as I am only beginning a deeper foray into the underlying science of tea. However, at this point, and given how much time Hojo has spent on the ground in various tea farms each year, I am inclined to trust for now his assertions around, at least, in part, modern elevated theanine content in tea being directly related to the use or overuse of nitrogen fertilizers.

Returning to pu-erh, the study I read last night also did a break down of the occurrence of GABA in the various types of teas. It states, "The GABA content was found to be the smallest in pu-erh tea (about 1.9mg/100g) corresponding to the paper by Zhao et al. (2011) who used OPA as derivitization reagent and a fluorescence detector for the determination of GABA in various types of tea."

The study is quite interesting and offers other useful information if anyone is interested.

Blessings!
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Re: Tea alkaloids and tea chemistry

Postby shah82 » Nov 27th, '13, 18:44

Has anyone ever had Hojo's puerhs? The only history here is our favorite Malaysian's experience with his Midi and a 2006 LBZ.
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Re: Tea alkaloids and tea chemistry

Postby 茶藝-TeaArt08 » Nov 27th, '13, 19:57

I bookmarked a couple studies that deal specifically with the questions/questioning put forth at the beginning of the thread as well as others (some noted below). One I set aside to read tonight is titled "Behavioral and molecular evidence for psychotropic effects in l -theanine" and was published in 2011.

I set aside these as well:

1.Contents of fluoride, lead, copper, chromium, arsenic and cadmium in Chinese Pu-erh tea
Lv, Hai-Peng; Lin, Zhi; Tan, Jun-Feng; Guo, Li
Food Research International , Volume 53 (2) Elsevier – Oct 1, 2013

2.Study on relative contents of principal components of different tea by infrared absorption spectroscopy
Xiaohui Zhao, Xiaohui Zhao; Lian-shui Zhang, Lian-shui Zhang; Zhi-chu Nie, Zhi-chu Nie; Rong-xiang Zhang, Rong-xiang Zhang; Xiao-wei Li, Xiao-wei Li
Institute of Electrical and Electronics Engineers — Jan 29, 2011

3.Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
Peter, Rogers; Jessica, Smith; Susan, Heatherley; C., Pleydell-Pearce
Psychopharmacology , Volume 195 (4) Springer Journals – Jan 1, 2008

4.Changes in theanine and caffeine contents of black tea with different rolling methods and processing stages
Ferda, Sari; Y., Velioglu
European Food Research and Technology , Volume 237 (2) Springer Journals – Aug 1, 2013

5.The effects of l -theanine, caffeine and their combination on cognition and mood
Haskell, Crystal F.; Kennedy, David O.; Milne, Anthea L.; Wesnes, Keith A.; Scholey, Andrew B.
Biological Psychology , Volume 77 (2) Elsevier – Feb 1, 2008

6.The chemistry of low molecular weight black tea polyphenols
Drynan, James Warren; Drynan, James Warren; Drynan, James Warren; Drynan, James Warren
Natural Product Reports , Volume 27 (3) Royal Society of Chemistry – Feb 10, 2010

7.Trace Metal Contents (Al, Cu and Zn) of Tea: Tea and Soil from Two Tea Plantations, and Tea Products from Different Provinces of China
M.H., Wong; Z.Q., Zhang; J.W.C., Wong; C.Y., Lan
Environmental Geochemistry and Health , Volume 20 (2) Springer Journals – Jun 1, 1998

8.Exposure and risk assessment for aluminium and heavy metals in Puerh tea
Cao, Hongbin; Qiao, Li; Zhang, Hui; Chen, Jianjiang
Science of the Total Environment , Volume 408 (14) Elsevier – Jun 15, 2010

Should be interesting!

Blessings
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Re: Tea alkaloids and tea chemistry

Postby TokyoB » Nov 27th, '13, 20:19

I look forward to hearing about the results, particularly relating to the presence of heavy metals in puerh (or maybe I don't want to know).
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