False Positive Results in the Vanillin-HCl Assay of Tannins in Sorghum Forage1
- M. F. Walton,
- F. A. Haskins and
- H. J. Gorz2
Vanillin-HC1 procedures are widely used for the assay of tannins in plants. In attempts to adapt such procedures for use with sorghum [Sorghum bicolor (L.) Moench.] forage it was found that false positive reactions resulted, that is, red color developed in the presence of HC1 with or without vanillin. Leucoanthocyanldins (monomeric proanthocyanldins) may be the constituents responsible for this red color. A “chloroform-HCl” procedure was developed for measuring leucoanthocyanldins in sorghum forage. The procedure avoids interference by chlorophyll or other chloroform-soluble constituents. With vanillin added to the solution, this procedure should also be useful for the assay of condensed proanthocyanidins (tannins).Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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