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Title: Powdered hide model for vegetable tanning II. hydrolyzable tannin

item Brown, Eleanor - Ellie
item Taylor, Maryann
item Bumanlag, Lorelie

Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2014
Publication Date: 1/2/2015
Publication URL:
Citation: Brown, E.M., Taylor, M.M., Bumanlag, L.P. 2015. Powdered hide model for vegetable tanning II. hydrolyzable tannin. Journal of American Leather Chemists Association. 110(2):19-20.

Interpretive Summary: Several different and poorly understood processes can accomplish the conversion of animal hides into leather, the most valuable byproduct of the U.S. meat industry. In previous research, ARS scientists developed protocols using powdered hide to elucidate tanning mechanisms. Vegetable tanning, using extracts from tree bark, is the oldest and least well understood of current tanning processes. In this study, we used powdered hide to compare the effects of tanning with hydrolyzable tannin (chestnut) and condensed tannin (quebracho). The hydrolyzable tannin, a smaller molecule, is more readily absorbed by the powdered hide than is the condensed tannin. It is equally effective at protecting against microbial attack, but less effective at increasing hydrothermal stability.

Technical Abstract: Vegetable tannages employ both condensed and hydrolyzable tannins. As part of our exploration of tanning mechanisms, we reported last year on interactions of the condensed tannin, quebracho, with powdered hide. In this study, the interactions of chestnut extract, a hydrolyzable tannin, with powdered hide samples are reported and compared with those of the condensed tannin. Hydrothermal stability of powdered hide treated with the hydrolyzable tannin reached a maximum of 75 deg C at a 40% offer, compared with 84 deg C for a similar offer of condensed tannin. The hydrolyzable tannin was much more effective at improving collagenase resistance, with nearly complete protection at <10% offer.