Pumpkin oil cake protein isolate films as potential gas barrier coating Original Research Article

This work was aimed to investigate the potential of PuOC protein isolate (PuOC PI) in preparation of biodegradable films at different pH values (2–12) and plasticizer content (0.3–0.6 g glycerol/g PuOC PI). Results showed that films could be formed in a wild range of pH, except at pH = 4–8. Films with 0.4 and 0.5 g glycerol/g PuOC PI were suitable for further analysis. The pH of film-forming solutions influenced all examined film’s characteristics. The amount of added glycerol significantly affected (p < 0.05) tensile strength, elongation at break and solubility of the films. Gas permeability of films with 0.4 g glycerol/g PuOC PI showed that these films represents an excellent barrier for O2, N2, CO2 and air. Obtained films have improved elongation at break and gas permeability characteristics compared to PuOC biodegradable films, thus they could be used as gas barrier stretch coating.