title: Barrier, structural and mechanical properties of bovine gelatin-chitosan blend films related to biopolymer interactions.
abstract: BACKGROUND
  The increased use of synthetic packaging films has led to a high ecological problem due to their total non-biodegradability. Thus, there is a vital need to develop renewable and environmentally friendly bio-based polymeric materials. Films and coatings made from polysaccharide polymers, particularly chitosans and gelatins have good gas barrier properties and are envisaged more and more for applications in the biomedical and food fields, as well as for packaging. In this study a casting method was used to develop an edible plasticised film from chitosan and gelatin. Aiming to develop a blend film with enhanced properties, the effects of mixing chitosan (CS) and gelatin (G) in different proportions (CS:G, 75:25, 50:50, 25:75, w/w) on functional and physico-chemical properties have been studied.
  
  
  RESULTS
  Mean film thickness increased linearly (R2 =0.999) with surface density of the film forming solution. An enhancement of mechanical properties by increasing the tensile strength (38.7±11 MPa for pure chitosan and 76.8±9 MPa for pure gelatin film) was also observed in blends, due to gelatin content.When the gelatin content in blend filmswas increased an improvement of both water vapour barrier properties [(4±0.3)×10(-10) g m(-1) s(-1) Pa(-1) for pure chitosan and (2.5±0.14)×10(-10) g m(-1) s(-1) Pa(-1) for pure gelatin, at 70% RH gradient] and oxygen barrier properties ((822.62±90.24)×10(-12) g m(-1) s(-1) Pa(-1) for blend film chitosan:gelatin (25:75 w/w) and (296.67±18.76)×10(-12) g m(-1) s(-1) Pa(-1) for pure gelatin was observed. Fourier transform infrared spectra of blend films showed a shift in the peak positions related to the amide groups (amide-I and amide-III) indicating interactions between biopolymers.
  
  
  CONCLUSIONS
  Addition of gelatin in chitosan induced greater functional properties (mechanical, barrier) due to chemical interactions, suggesting an inter-penetrated network.
authors.forename: Nasreddine
authors.initials: N
authors.lastname: Benbettaïeb
authors.forename: Mia
authors.initials: M
authors.lastname: Kurek
authors.forename: Salwa
authors.initials: S
authors.lastname: Bornaz
authors.forename: Frédéric
authors.initials: F
authors.lastname: Debeaufort
mesh_terms: D000818:Animals; D001704:Biopolymers / Q000737:chemistry*; D002417:Cattle; D048271:Chitosan / Q000737:chemistry*; D018857:Food Packaging; D005780:Gelatin / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D010968:Plasticizers / Q000737:chemistry; D012995:Solubility; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: D001704:Biopolymers; D010968:Plasticizers; C015233:gelatin film; D014867:Water; D005780:Gelatin; D048271:Chitosan; D010100:Oxygen