Physical and transport proferties of edible films composed of galactomannan and chitosan

Edible films and coatings can provide additional protection for food, while being a fully biodegradable, environmentally friendly packaging system. The main objective of the study was to produce edible films and coatings based on chitosan and galactomannan of A. pavonina L., with the incorporation of sodium acetate and characterize them as to their physical properties. Films were cast and, the water vapor, O2 and CO2 permeabilities of the films were determined, together with their solubility in water, opacity, color and mechanical properties. The film of chitosangalactomannan with the addition of sodium acetate had lower permeability to water vapor (1.40 ± 0.02 (g.(m.day.atm)-1)) and elongation at break (67.11 ± 0.89%) being the most rigid film for presenting the highest Youngs modulus (35.68 ± 0.64 MPa). The blends showed the highest values of maximum voltage and breakdown voltage. The films based on galactomannan had a decreased permeability to O2 of 0.20 to 0.18 x 10-12 (g.(m.Pa.s.m2)-1, incorporating sodium acetate, also showing high permeability to CO2. The chitosan film without addition of sodium acetate had low lightness value L * (81.23 ± 1.43) and a higher opacity compared with the film containing acetate, suggesting that incorporation of sodium acetate increased transparency of the film. The films containing chitosan exhibited low water solubility and high b* component values, indicating the predominance of yellowing. The reported results is important once it will reduce the characterization work needed in subsequent applications of these coatings/films on foods