Improvement in physicochemical properties of collagen casings by glutaraldehyde cross-linking and drying temperature regulating.

The physicochemical properties of collagen casings were successfully improved by glutaraldehyde (GA) cross-linking, where the properties could be further regulated by drying temperature. Transverse direction (TD) showed a lower heat shrinkage rate than that in machine direction (MD). GA cross-linking significantly improved the mechanical properties of films under wet and boiled state. The mechanical properties of films in MD were more susceptible to wet and boiling water. The chemical composition was unchanged after GA cross-linking, but higher drying temperatures led to higher triple helix contents. The GA cross-linking mainly promoted the low temperature thermostability of collagen casings. All film samples had a rough fibrous morphology and a majority of collagen fibers was oriented under the lower drying temperature (55 ℃). These results reported in this study can be used to better guide the preparation of collagen casings.