Edible protein films: properties enhancement

Edible films can be prepared from protein, polysaccharide and lipid materials. Among them, proteinbased edible films are the most attractive. These films have impressive gas barrier properties compared with those prepared from lipids and polysaccharides. The mechanical properties of protein-based edible films are also better than those of polysaccharide and fat-based films because proteins have a unique structure (based on 20 different monomers) which confers a wider range of functional properties, especially a high intermolecular binding potential. However, the poor water vapor resistance of protein films and their lower mechanical strength in comparison with synthetic polymers limit their application in food packaging. Hence, improvement of edible protein film properties has been investigated to seek suitable applications. The objective of this review is to provide a detailed enhancement of the properties of edible protein film through using various methods such as modifying the properties of protein by chemical and enzymatic methods, combining them with hydrophobic material or some polymers, or using a physical method. These methods focus primarily on improving the mechanical strength and moisture barrier properties.