More specifically, what would be the most appropriate standard(s) for quantifying total phenolics or tannins in samples that contain mixtures of both hydrolyzable & condensed tannins? Assume you don't know proportion of the two tannin types in the mixture or have no readily available tool to determine.
Toyed with catechin, gallic acid and combinations to build calibration curves but to no avail.
The total polyphenolic compounds can be determined as the sum between the hydrolysable polyphenols and condensed polyphenols, hydrolysable polyphenols can be determined according to the methodology of folin ciocalteu (galic acid) and condensed polyphenols content can be evaluated by the method HCl-butanol (catechin) described by Swain & Hillis, (1959).
You can add the two and have a correct value of the content of phenols
Hello. There is a group from Spain, who works with the determination of condensed and hydrolyzable tannins. What they do is to realize the normal extraction of phenolic compounds in the sample. Then, the residue obtained after the extractions is hydrolized with H2SO4 or HCl-Buthanol (hydrolyzable and condensed tannins, respectively). At the end, for hydrolizable tannins, you can use a standard curve of Gallic acid and a standard curve of cyanidin for condensed tannins.
Search papers from Saura-Calixto, F, Goni, I, Serrano J., Perez-Jimenez, J, Tabernero, M.
Phil,
I concur with your assessment and it would appear we have an additional vote from Maribel regarding best approach. I'll give the acid-butanol and acid hydrolysis followed by HPLC some more thought. More than likely I will be working with other proanthocyanidins beyond procyanidins. Not expecting any A-types fortunately. Will consider phloroglucinolysis as well. Degradation aside, this approach seems to be the most viable.
Thanks all for the responses. Warm regards, Mark
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Infectious Diseases