Physical and antifungal properties of hydroxypropylmethylcellulose based films containing propolis as affected by moisture content

Edible films based on hydroxypropylmethylcellulose (HPMC) and different concentrations of an ethanolic extract of propolis (EEP) were obtained. Film-forming dispersions (FFDs) were characterized in terms of pH, density, rheological properties, particle size distribution and ζ-potential. Dry films were evaluated in terms of their optical, mechanical and water barrier properties when equilibrated at different moisture conditions. Likewise, the antifungal activity of the films against Aspergillus niger and Penicillium italicum was studied. The incorporation of EEP affected the pure film properties by improving the water vapour permeability and giving rise to more rigid, less flexible and deformable, more opaque and coloured films with lower gloss and transparency. The composite films revealed a notable antifungal activity against the tested fungus, showing a greater inhibitory effect on A. niger.