Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/23/2005
Publication Date: 6/1/2006
Citation: Taylor, M.M., Marmer, W.N., Brown, E.M. 2006. Preparation and characterization of biopolymers derived from enzymatically modified gelatin and whey. Journal of American Leather Chemists Association. 101(6):235-248. Interpretive Summary: Petroleum feedstuffs have been dramatically increasing in cost and, as a result, there is considerable interest in the use of products from renewable resources for the production of goods that were customarily made from these traditional raw materials. In prior research from this laboratory, we enzymatically combined gelatin with varying amounts of a sustainable resource from the dairy industry, casein, to form biopolymers, and the resultant products have the advantage of possessing the unique properties of each protein and, at the same time, have the potential for generating novel products. In this present study, we examined individually the properties of enzymatically modified gelatin and whey (a low cost waste product from the dairy industry), as well as their combined products. The physical properties and degree of polymerization of the gelatin biopolymers showed that the level of modification was enhanced by addition of even small amounts of whey, the secondary protein. Furthermore, with the assistance of an enzyme, the gelatin and whey were applied to tanned leather as fillers and the results show that the proteins were evenly distributed throughout the hide and more importantly were bound. Thus these reactions between dissimilar proteins (from renewable resources) have the potential to be used in leather processing as economical replacements to petroleum-based fillers and potentially as coatings.
Technical Abstract: Many authors have reported that biopolymers can be formed from enzymatic crosslinking between dissimilar proteins. It was shown that these products have the advantage of possessing the unique properties of each contributing protein and, at the same time, have the potential for generating innovative products. In this present study, we examined separately the properties of microbial transglutaminase-modified proteins, specifically gelatin, whey, and whey protein isolate (WPI), as well as their enzymatically-combined products. The physical properties and molecular weight distribution of the gelatin biopolymers show that the products had higher melting points, viscosities, and molecular weight distributions, and the degree of crosslinking was enhanced by addition of even small amounts of the secondary protein. There is potential that these products from relatively inexpensive sustainable resources may be used as fillers or as coatings in leather processing. To that end, we carried out a filling experiment, using labeled proteins, and showed that the proteins were evenly distributed throughout the hide and, more importantly, were bound and not removed during the washing steps.