A Method for Isolating Condensed Tannins from Crude Plant Extracts with Trivalent Ytterbium

A method to precipitate condensed tannin from crude plant extracts using trivalent ytterbium has been developed. The new method requires less time and resources than the condensed isolation procedure using Sephadex LH‐20 recommended by Hagerman (1991, Tannin Analysis, Miami University, Oxford, OH, U...

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Bibliographic Details
Published in:Journal of the science of food and agriculture 1997-07, Vol.74 (3), p.359-368
Main Authors: Giner-Chavez, Bertha I, Van Soest, Peter J, Robertson, James B, Lascano, Carlos, Reed, Jess D, Pell, Alice N
Format: Article
Language:English
Subjects:
Biological and medical sciences
condensed tannin
extraction
Feed and pet food industries
Food industries
Fundamental and applied biological sciences. Psychology
proanthocyanidins
ytterbium
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Summary:A method to precipitate condensed tannin from crude plant extracts using trivalent ytterbium has been developed. The new method requires less time and resources than the condensed isolation procedure using Sephadex LH‐20 recommended by Hagerman (1991, Tannin Analysis, Miami University, Oxford, OH, USA). The absorbance of the preparations obtained by precipitation with trivalent ytterbium was similar to the preparations obtained with the original isolation procedure, when the acid butanol method (Porter et al 1986, Phytochemistry 1 223–230) was used to measure condensed tannins. Condensed tannins were isolated from crude plant extracts of three plant species, Desmodium ovalifolium, Gliricidia sepium and Manihot esculenta, and the condensed tannin content of the lyophilised leaf tissue was determined. For each plant species, the amounts of the soluble, insoluble and fibre‐bound condensed tannins were estimated using five different standards. These standards included two tannin preparations obtained either by (1) isolation with Sephadex LH‐20, or (2) by the precipitation with trivalent ytterbium and three external standards: (3) cyanidin, (4) delphinidin and (5) purified quebracho (Schinopsis balansae). When external standards were used (cyanidin, delphinidin, purified quebracho), it was likely that the condensed tannin content of the plant tissue would be under‐ or overestimated. When an internal standard based on the isolated tannin from the respective plant species was used, accurate estimates were obtained. © 1997 SCI
ISSN:0022-5142
1097-0010
DOI:10.1002/(SICI)1097-0010(199707)74:3<359::AID-JSFA811>3.0.CO;2-C