The preparation and physiochemical characterization of rapeseed protein hydrolysate-chitosan composite films.

The composite films were prepared by mixing rapeseed protein hydrolysate with chitosan. Upon increasing the degree of hydrolysis, rapeseed protein enhanced its compatibility with chitosan, thus making composite films denser. The tensile strength of films was increased from 16.04 to 23.46 MPa with increasing the degree of hydrolysis from 0% to 12%. Moreover, addition of chitosan enhances the mechanical properties of the rapeseed protein films, the α-helix content in the secondary structure of the rapeseed protein from 15.4% to 25.0%. And it is hydrogen bonding, the main force between two components that contributed to good compatibility, which supported by analyses of Fourier transform infrared spectroscopy and scanning electron microscopy. The results of the antibacterial properties of the composite film with 12% degree of hydrolysis were better compared with the chitosan film. Taken together, our results provide insights for the further application of rapeseed protein in making edible films.