Mechanical and barrier properties of cross-linked soy and whey protein based films

Sterilized biofilms based on soy protein isolate (SPI, S system) and a 1:1 mixture of SPI and whey protein isolate (WPI, SW system) were achieved thro ugh the formation of cross-links by means of gamma -irradiation combined wi th thermal treatments. The effect of the incorporation of carboxymethylcell ulose (CMC) and poly(vinyl alcohol) was also examined. gamma -Irradiation c ombined with thermal treatment improved significantly the mechanical proper ties, namely, puncture strength and puncture deformation, for all types of films. Irradiated formulations that contain CMC behave more similarly as el astomers. CMC showed also significant improvements of the barrier propertie s, namely, water vapor permeability, for irradiated films of the S system:a nd for non-irradiated films of the SW system.