Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2006
Publication Date: October 1, 2006
Citation: Ding, K., Taylor, M.M., Brown, E.M. 2006. Effect of Genipin on the Thermal Stability of Hide Powder. Journal of American Leather Chemists Association. 101(10):362-367. Interpretive Summary: Tanning of animal hides or skins produces leather, a high value co-product of the meat industry. Salts of the mineral chromium are the most commonly used tanning agents for the production of high quality leathers. Because of environmental considerations, and customer preference, the tanning industry is interested in developing chrome-free tannages. Although the art of tanning is highly developed, the mechanisms are poorly understood. The research reported here is a first step in the evaluation of genipin, a small molecule isolated from the fruit of the gardenia plant, as a potential tanning agent. The tanning effect of genipin was found to be similar to that of glutaraldehyde, an organic tanning agent currently being used to produce chrome-free leather. A major advantage of genipin over glutaraldehyde is a much lower level of toxicity. The development of genipin as a tanning agent could provide the leather industry with a biofriendly, safe formulation for production of high quality chrome-free leathers.
Technical Abstract: Genipin, derived from the iridoid glycoside geniposide isolated from the fruit of Gardenia jasminoides Ellis, is a naturally occurring protein crosslinking agent. Genipin, which is not cytotoxic, is beginning to replace glutaraldehyde as a fixative for biological tissues. This study was undertaken to evaluate the potential of iridoid compounds, in particular genipin, for use as tanning agents. The tanning effect of genipin on bovine hide powder was investigated. Parameters including the dosage of genipin, reaction time, pH and temperature of the tanning process were varied. The peak temperature (Tp) obtained by differential scanning calorimety (DSC) of treated hide powder was used to evaluate the tanning effect. The results indicated that treating hide powder with 5% genipin at pH ~ 7 and 35 deg C for 24 hours increased Tp from 60 deg C to 79 deg C. A secondary observation was that the tanned hide powder exhibited a dark blue color. A likely mechanism for genipin tanning is discussed. These results provide a new potential approach to chromium-free tanning for the leather industry.