Influence of different concentrations of Zn-carbonate phase on physical-chemical properties of antimicrobial agar composite films

Agar-based composites with different Zn-carbonate mineral phase content were prepared by in situ mineralization and the solvent casting method. The mineral phase within the composite films was identified as hydrozincite, Zn5(CO3)2(OH)6. The presence of the mineral phase improved, both mechanical and water vapor permeability properties of the obtained composite films, in a concentration-dependent manner. The release of zinc ions from composite films is in accepted levels (up to 2.5%), and sufficient to provide complete inhibition growth of S. Aureus. The results of this study suggest that agar/Zn-carbonate composites could be potentially used as affordable, eco-friendly and functional materials with tunable properties for food packaging, agriculture or biomedical application. In situ procedure offers possibilities for tailoring the physical-chemical properties of composite films, by varying the Zn-mineral phase load.