[mehc]

Are tannins and polyphenols exactly same thing?
I have found that tannins are polyphenols. But I was confused as in AOAC, there is use of Folin-Dennis reagent for quantitative determination of tannins from tea. But for determination of polyphenols from lemon juice, it was different spectrophotometric method.

I want to know that in official methods of analysis (AOAC), if I find a method for determination of tannin, does it mean that it's a method for polyphenols?
In other words can we say that Folin-Dennis spectrophotometric method is an official method for polyphenols determination?
thanks

[sjb]

Looking through, e.g. http://en.wikipedia.org/w/index.php?title=Tannin&oldid=280294327 and http://en.wikipedia.org/w/index.php?title=Polyphenol&oldid=278497546 the suggestion I get is that polyphenols are tannins, but tannins are not necessarily polyphenols.

S

[mehc]

Thanks,
From Wikipedia, I also got the idea that all tannins are not polyphenols.

But It's not true as I 've recently found in a book and want to share.
"Not all polyphenolic compounds are tannins but all tannins are polyphenols".