Effects of Fillers Prepared from Enzimatically Modified Proteins on Mechanical Properties of Leather

In an environment where petroleum feedstuffs are becoming increasingly too expensive for a good cost-effective return, utilization of renewable resources makes economic sense, particularly when these substrates are waste proteins. We have thus proposed the application of enzymatically modified waste proteins from the leather (gelatin) and dairy (casein and whey) industries as fillers in leather production. In previously reported research, we prepared different combinations of these waste proteins, enzymatically modified them, characterized the products and applied them to blue stock using fluorescently labeled proteins to determine how they were distributed in the hide and more importantly not removed by washing. From the data acquired in these previous experiments, we identified potential filling materials. We now have treated various areas in the hide (butt, belly, and neck) with the products, retanned, colored and fatliquored the treated pieces, evaluated them with respect to subjective properties against controls, and finally determined mechanical properties. The results from these tests show that the mechanical properties were not significantly affected by the treatment and subjective properties, e.g., handle, fullness, break and color, were improved over the controls. Fillers thus have the potential to be economically produced from sustainable resources as an alternative to more expensive and increasingly limited conventional products.