Effect of polymer mixture on bioplastic development from fish waste

The bioconversion of protein from the fishing industry waste into bioplastics allows the valorization of biological material, reducing the production of waste and consequently of negative environmental impacts through the use of synthetic packaging. The objective of this work was to develop biodegradable films from the mixture of gelatin and myofibrillar fish proteins. Proteins (myofibrillar and gelatin) were extracted from filleting residues from king weakfish (Macrodon ancylodon) from industrial fishing. The properties of the blend films were compared to those of individual protein films. It was found by scanning electron microscopy that there was good compatibility between the two polymers. Mechanical analyzes showed that myofibrillar proteins films were the most resistant to traction, but less flexible; characteristics contrary to those of gelatin. The mixing films presented the lowest values of water vapor permeability and solubility were transparent, and mechanically strong and flexible, confirming the improvement of the properties by mixing the polymers. Fourier transform infrared spectroscopy revealed that there was interaction between the myofibrillar protein chains and gelatine driven by hydrogen bonds, thus forming cohesive and reinforced matrix, which resulted in good thermal resistance of the films. The mixture between polymers improved the technological properties of the elaborated biodegradable films, making its application feasible as food packaging.