The conditioning relative humidity influences the gas permeability of active films and nanocomposites based on gelatin

The influence of relative humidity on O2 and CO2 permeability of gelatin-based films and nanocomposites incorporated with crystalline nanocellulose (CN), non-encapsulated “Pitanga” (Eugenia uniflora L.) leaf extract (PLE) or encapsulated in a water-in-oil-in-water double emulsion (DE) was studied. Cross-section morphology by scanning electron microscopy, crystallinity, moisture content, thickness, and O2 and CO2 transmission rate (GTR) were determined. The addition of CN, PLE, and/or DE caused changes in the morphology and crystallinity of the films and nanocomposites. In general, the GTR in films and nanocomposites increased with increasing relative humidity due to the swelling effects and plasticizing effect of water. Nanocomposites with non-encapsulated PLE or DE showed good oxygen barrier properties at high relative humidity. The outcome of this study was that the addition of CN with PLE or DE improved the gas barrier properties of gelatin-based films, especially in high relative humidity conditions. Highlights: “Pitanga” leaf extract (PLE) was encapsulated in a double emulsion (DE). Crystalline nanocelluloses (CN) were extracted from soybean straw. Gelatin nanocomposite films were produced with CN and activated by PLE or DE. Relative humidity (RH) influences the O2 and CO2 permeability in the films. The nanocomposite film with CN/DE showed low permeability to gases at high RH.