|Brown, Eleanor - Ellie|
Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2006
Publication Date: 7/1/2006
Citation: Brown, E.M., Stauffer, D.M., Cooke, P.H., Maffia, G.J. 2006. The effect of ultrasound on bovine hide collagen structure. Journal of American Leather Chemists Association. 101(7):274-283. Interpretive Summary: Animal hides and skins are the highest value co-products of the meat industry. These hides and skins consist primarily of the protein, collagen, which is processed to make leather and other biomaterials. Typical processing methods are time consuming and may require the use of chemicals in excess of those appearing in the final product, thus creating an additional disposal expense. Ultrasonic production techniques are now being used in the textile industry and occasionally in leather finishing. The research reported here examines the effect of ultrasound on dispersions of crude collagen such as might be used in the production of biomaterials. The results showed a slight opening up of supramolecular collagen aggregates, but no damage to the collagen molecules. This opening up effect would be beneficial in the production of biomaterials or leather, because it will improve the penetration of processing chemicals into the collagen matrix. An additional benefit to the tannery would be more rapid and complete removal of small noncollagenous components of the hide.
Technical Abstract: Applications of ultrasound in leather processing have been researched for more than 50 years. Although these studies showed that ultrasound could have beneficial effects on hide preparation, tanning and finishing processes, the costs associated with the development of a new technology outweighed the benefits. Ultrasound is now a mature science, used to improve the efficiency of processes for the manufacture of a variety of materials. It may well offer a path toward the use of fewer (less) chemicals in the production of quality leather. However, the effects of ultrasound on the structure and function of biomacromolecules, specifically protein complexes, have not been extensively studied. This research examines the chemical, physical and mechanical effects of ultrasonic treatment on bovine hide collagen. Scanning electron micrographs show that low frequency, high power ultrasound (20 kHz) appears to unravel the 50 - 100 nm fibrils, seen in ball-milled collagen, into smaller diameter fibrils. Although these smaller fibrils are more susceptible to attack by collagenase, the individual collagen molecules remain intact as demonstrated by SDS-PAGE. Soluble and insoluble collagen and hide powder are also being examined to develop a broader picture of potential effects of ultrasound in leather manufacturing.