AROMA COMPOUND AND WATER-VAPOR PERMEABILITY OF EDIBLE FILMS AND POLYMERIC PACKAGINGS

The permeability of water vapor and aroma compounds through low-density polyethylene packagings and edible films was measured with a dynamic method coupled with a gas chromatograph. Volatile fluxes were analyzed and quantified with two detections: thermal Conductivity and flame ionizing detectors. The effects of overpressure and aerodynamic conditions inside the permeation cell were determined, and vapor concentration differentials were only used to measure permeability. Water vapor and aroma permeabilities increase with the penetrant sorption within the film, particularly for hydrophilic films such as cellophane or edible films. Whatever the nature of the penetrant, polar (water vapor) or apolar (1-octen-3-ol), the behavior of edible films and the activation energy of permeation are identical. However, aroma transfer through methylcellulose-based films strongly increases with the water vapor transfer rate (WVTR) due to the plasticization of the polymer network by water. WVTR directly depends on the hydrophobicity of the polymer, but not for 1-octen-3-ol flux.