A top-down approach to improve collagen film's performance: The comparisons of macro, micro and nano sized fibers.

The severe reduction of mechanical strength of collagen once it is extracted or dissociated from animal tissues and no additional crosslinking approaches are conducted, impede its application in biodegradable and edible food packaging. Here, for the first time, high pressure homogenization (HPH) was used to prepare diverse sized fibers and the related fibers-composed films' performance were investigated. These fibers have a diversity of effects on film performance. The films prepared with smaller sized fibers had a more uniform and denser structure. The mechanical and the water barrier properties of the films improved significantly as the fiber size decreased. No obvious change in FTIR and thermal properties suggests that the improved film performance is mainly attributed to the physical entanglement and non-covalent bonds. Given the forementioned benefits of the films, control of fiber size can be a potential industrial approach for producing collagenous materials in edible food packaging.