Preparation and characterization of collagen food packaging film

Collagen was extracted from the skin of pigs, and blended with sodium alginate, starch, and sodium carboxymethyl cellulose. Food packaging films were obtained by crosslinking the blend with glutaraldehyde. Fourier transform infrared spectroscopy (FT-IR), SEM and TGA analyses were used to characterize the resulting films. A strong hydrogen bonding was detected between the composite film molecules. Mechanical measurements show that the elongation at break and tensile strength of the films are significantly improved after addition of sodium alginate. A network structure is formed due to crosslinking of collagen molecules by glutaraldehyde. Addition of sodium alginate enhances the interaction between molecules in the film. On the other hand, collagen is well compatible with sodium carboxymethyl cellulose, sodium alginate and starch. The surface morphology of the film appears more homogeneous after crosslinking. The combined effects of these factors allowed to improve the mechanical properties of the collagen-based films.