Development and characterization of active films based on starch-PVA, containing silver nanoparticles

In order to obtain antimicrobial packaging films, starch-PVA-based films with silver nanoparticles (AgNPs) have been developed and characterized as to their physical and antimicrobial properties and silver release kinetics to polar (A, B, C and D1) and non-polar (D2) food simulants. Antimicrobial activity against two bacteria, Listeria innocua and Escherichia coli, and two fungi, Aspergillus niger and Penicillium expansum, was studied. Silver-loaded starch-PVA films exhibited antimicrobial activity against the tested microorganisms, which depended heavily on the concentration of AgNPs. Their addition only led to notable physical changes in the colour and transparency of the films, which underwent significant changes and turned brownish-yellow and opaque, this being more notable when the silver concentration rose. Silver was released into aqueous simulants in its entirety within the first 60 min of contact. In the non-polar simulant (oleic acid), the release capacity of the films drastically decreased, being the only case where the established limit (60 mg/kg simulant) was met. As a consequence, the use of the developed films as food packaging materials should be restricted to fat-rich foodstuffs. (C) 2016 Elsevier Ltd. All rights reserved.