Talk:Phenolic content in tea

The citing of old scientific papers to name tea polyphenols as tannins is inaccurate. The major polyphenols in tea is the group of catechins that are simple molecules and not tannins that are built by the oxidase of phenolic substances. Theaflavins and thearubigins in black tea are also larger structure built from catechins, but not as much. Catechins, theaflavins and tannins are different in both chemical characteristics and health nature. Therefore it is important not to confuse the reader with such concept as tannin, although people in the old time often mistake them.

Not all polyphenols taste astringent. Theaflavins and tannins do. Catechins are more bitter than astringent. Some catechins are bitter with sweet after taste.

I shall proceed to make amendments with proper research papers to upgrade this article to proper Wiki standard.

Bill Ukers (talk) 10:56, 17 February 2011 (UTC)

No point in giving a big section on "fermentation" in this topic
Processing for black tea oxidizes the catechins and turn them into other forms of flavonoids, but there is no point in making fermentation a section in this topic which focus is about the nature of polyphenols, not tea processing. The other Wiki article about tea processing already take care of the issue. The focus should be the change of nature of the polyphenol rather than the processing itself. Bill Ukers (talk) 14:23, 18 February 2011 (UTC)


 * Not to quibble excessively but this article is not about polyphenols but rather polyphenols in tea. If the enzymatic oxidization of the polyphenols in the tea leaves is yielding theaflavins and thearubigins, then it would seem that this section plays a valid role. This article has the difficulty of balancing the historic (but imprecise/incorrect) word usage with the accurate modern scientific usage. jmcw (talk) 14:40, 18 February 2011 (UTC)

Hello jmcw, Thank you for responding so quickly to my comments. I understand where you are coming from and agree that the changes should be mentioned. This article can either go chemistry specific as in the article of polyphenols or catechins, or it can go more easy reading with links to the two more specific ones. Since if you read the catechins article in Wiki, it pretty much covers the transformation in chemistry terms. So I have modified it anyway as here in the second direction and I believe that you'd like to see the balance I propose here.

Thank you also for adjusting the caption of the gaiwan to say oolong, but I think it is more appropriate to use a green tea photo since this is more a comparison between the green and the black. I hope you agree. Bill Ukers (talk) 16:41, 18 February 2011 (UTC)

Wrong picture use
Also the picture that is supposing to be green tea now is actually an oolong tea in the gaiwan. The leaves clearly indicate that from an oolong cultivar, possibly a light fermentation Anxi style of low to medium quality. It is NOT a green tea. Someone please change that picture, I do not know how to do it.

The other picture with a cup of black tea there is not adding any illustrative point to this article so I am deleting it. As for the picture of the Darjeeling I think it is worth keeping to show the difference between a black tea and a green tea, but it is irrelevant in this article to caption it as not fully fermented, this article is not about taste profile of various tea selections. Furthermore, there are various styles of Darjeeling black tea with various processing styles so it is inappropriate to mention just one style without mentioning another in the context of an encyclopedia that is Wiki. I'll change the caption.

Bill Ukers (talk) 14:31, 18 February 2011 (UTC)

White tea, oolong, and red tea and EGCG and Flavnoids
This article does not mention the percentage/mg of EGCG or Flanoids in either Red tea (rooibos) or white tea, they should be added, as well as other types of tea such as oolong. —Preceding unsigned comment added by 64.134.102.154 (talk) 00:11, 3 May 2011 (UTC)

The percentage of various phenolic compounds in various categories of tea varies dramatically between different selections, i.e. they are not defined by the category but rather by quality differences. Datas from different reports also vary drastically because of measurement methods and the quality accessible to the particular group of scientists. If you are interested, green tea generally has much higher catechins content, that includes EGCG. Most respectable quality green tea has roughly 20 to 30% dry weight of that. However, lower quality products can be with negligible amount. The amount of some other phenolic compounds, such as that for thearubigens in black tea may not have any health relevance, though their quantity can be countable. The scientific community has not found any significant health contributive evidence of it. Listing its relative high amount (can be something like 18% on the high) can mislead the reader to think that there is equal health evidence in both green and black tea. A comprehensive list here could be extremely controversial, esp against mass market beverage manufacturers. A quantitative list here in this popular platform also requires a qualitative explanation of all the compounds involved, which is a major task, even without the back-fire from certain powerful corporations with loads of publicity budget. Teaguardian.com has a rather readable feature on tea polyphenols at: http://teaguardian.com/TeaPolyphenolSpecialEdition.html, if you are more serious about reading the truth of things.

Bill Ukers (talk) 14:42, 13 May 2011 (UTC)

Teaguardian.com
After extensive exploration of the site, I feel strongly that teaguardian.com does not meet the WP:RS guidelines. It also struck me as possible WP:CITESPAM, because of how heavily it was included in the page, although I did not check the edit history so it could have been added legitimately by an editor unfamiliar with the reliable source guidelines. Please be cautious about what you add. That is a self-published site. It identifies itself as "is a self-financed, independent reference guide". This is not acceptable for use as a source. That site does cite some specific studies in more reliable sources. If you want to use it, go retrieve those studies and use them as sources here. Cazort (talk) 16:40, 23 November 2011 (UTC)

Deletion of categories Chemical compounds found in foo and Phenolic compounds found in bar
Category:Chemical compounds found in Acanthaceae and related categories of the form Chemical compounds found in foo and Phenolic compounds found in bar have been nominated for possible deletion. If you would like to participate in the discussion, you are invited to add your comments at the category's entry on the Categories for discussion page. Thank you. --Kkmurray (talk) 16:48, 21 September 2013 (UTC)