Journal
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
Volume 85, Issue 10, Pages 1647-1650Publisher
JOHN WILEY & SONS LTD
DOI: 10.1002/jsfa.2163
Keywords
polymerisation; Uapaca kirkiana; Ziziphus mauritiana; chromogenic; vanillin
Ask authors/readers for more resources
Methanol and glacial acetic acid were compared for their effect in the vanillin assay for tannins. The time taken for the development of colour was followed using a spectrophotometer. By reacting vanillin and condensed tannins in the presence of acetic acid, the time for the development of the chromogenic substance was reduced approximately threefold compared with the time taken in the presence of methanol. The degree of polymerization was followed by reacting a catechin standard, the tannin of the Uapaca kirkiana and Ziziphus mauritiana, with vanillin in acetic acid medium at 30 degrees C and measuring absorbance at intervals. The values obtained suggested between 4 and 10 monomer units of catechin per polymer of tannins for the different portions of the two fruits. (c) 2005 Society of Chemical Industry.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available