Location: Biobased and Other Animal Co-Products
Title: Treatment of hides with tara-modified protein products Authors
|Liu, Cheng Kung|
Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 16, 2013
Publication Date: December 1, 2013
Citation: Taylor, M.M., Medina, M.B., Lee, J., Bumanlag, L.P., Latona, N.P., Brown, E.M., Liu, C. 2013. Treatment of hides with tara-modified protein products. Journal of American Leather Chemists Association. 108:438-444. Interpretive Summary: We have demonstrated that products made from chemically or enzymatically modified proteins could improve the quality of leather and recently showed that comparable products could be made by modifying these proteins using the polyphenols found in renewable vegetable tannins. We established that the tannin tara, when used to modify gelatin, would give products that could be used in leather finishing. The advantages to using tara is that it gives a light colored product and imparts light fastness to the leather, but most important it is truly sustainable for it is extracted from the fruit husks of a small tara tree. Optimal conditions for modification of gelatin by tara were determined and, in this continuing study, appropriate products were applied to hides to determine if we could improve the quality of the resultant leather. The subjective properties of the leather (for example, softness and fullness) were significantly improved over control samples that were not treated. The mechanical properties (for example, the ability to tear the leather) were not different than the control samples. At the same time, by applying a method developed at ERRC for determination of phenolics, we were able to measure the uptake of the product. Hence gelatin, a byproduct from the leather industry, modified with tara, a commonly employed and renewable tanning agent, could be utilized to improve leather products.
Technical Abstract: In prior research, we demonstrated that gelatin could be modified with quebracho to produce products whose physicochemical properties would enable them to be used effectively as fillers in leather processing, and that leather resulting from this treatment had improved subjective properties with little effect on mechanical properties. In an extension of the study, the tannin, tara was examined for its potential in gelatin modification. The advantage for using tara is that it gives an almost colorless product, which would be desirable in production of light colored leather, as well as imparting light fastness to the leather. The conditions for optimal tara modification of gelatin were determined and the products characterized. In this present study, these tara-modified gelatins were evaluated as fillers in the treatment of wet blue and wet white. In addition, the rate of uptake of the product was also examined using an analysis developed at ERRC for the measurement of polyphenolics in foods. It was found that the treated leathers, when evaluated for their subjective properties (handle, fullness, break and color), demonstrated improved properties. There were no significant differences in test and control samples of wet blue and wet white, with respect to the mechanical properties (tensile, elongation Young’s Modulus, toughness index and tear strength. SEM examination of fiber structure showed differences in treated and untreated samples. Thus, another sustainable, economical resource, the polyphenolic tara, in conjunction with gelatin, has further shown its potential for use in leather production.