Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): James K. Nitao; Bruce A. Birr; Muraleedharan G. Nair; Daniel A. Herms; William J. Mattson
    Date: 2001
    Source: Journal of Agriculture and Food Chemistry. 49: 2207-2214.
    Publication Series: Scientific Journal (JRNL)
    Station: Northern Research Station
    PDF: View PDF  (121.64 KB)


    Proanthocyanidins (condensed tannins) frequently need to be quantified in large numbers of samples in food, plant, and environmental studies. An automated colorimetric method to quantify proanthocyanidins with sulfuric acid (H2SO4) was therefore developed for use in a continuous flow analyzer. Assay conditions were optimized using 50% methanol extracts of paper birch, sugar maple, and quaking aspen leaves. Short extraction times and centrifugation of samples prevented proanthocyanidin degradation that otherwise occurred in 50% methanol extracts of aspen leaves. Extraction of birch and maple proanthocyanidins with 50% methanol was comparable to or better than that with 70% acetone. Proanthocyanidin levels in aspen were lower when extracted with aqueous methanol, but relative differences among samples were consistent with those found in aqueous acetone extracts. Results from the automated sulfuric acid assay were highly correlated with those of the conventional BuOH-HCl method for proanthocyanidins and, except for birch, with the Folin-Denis assay for total phenolics. This new technique significantly improves assay processing rate and repeatability compared to conventional colorimetric proanthocyanidin assays.

    Publication Notes

    • Check the Northern Research Station web site to request a printed copy of this publication.
    • Our on-line publications are scanned and captured using Adobe Acrobat.
    • During the capture process some typographical errors may occur.
    • Please contact Sharon Hobrla, if you notice any errors which make this publication unusable.
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Nitao, James K.; Birr, Bruce A.; Nair, Muraleedharan G.; Herms, Daniel A.; Mattson, William J. 2001. Rapid quantification of proanthocyanidins (condensed tannins) with a continuous flow analyzer. Journal of Agriculture and Food Chemistry. 49: 2207-2214.


    proanthocyanidins, condensed tannins, colorimetric assay, Betula, Acer, Populus

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page