Characterization of silver nanoparticles loaded chitosan/polyvinyl alcohol antibacterial films for food packaging

Abstract

Sliver nanoparticles (AgNPs) were loaded on chitosan (CS) and incorporated into polyvinyl alcohol (PVA) to develop novel active food packaging films. AgNPs were fabricated by liquid phase chemical reduction method using CS and sodium citrate friendly reductant of AgNO3. The silver we prepared was found to be nanoscale by transmission electron microscopy (TEM) and AgNPs were homogeneously dispersed in the matrix by scanning electron microscopy (SEM). The composite film exhibited excellence mechanical properties with tensile strength of 49.97 MPa and elongation at break of 275.90%. When the concentration of AgNPs was 0.019% (w/w), the diameter of filter paper was 5.00 mm and the inhibition zone against Escherichia coli reached 16.07 mm at 37 °C for 8 h. The water vapor permeability and water solubility of the Ag@CS/PVA films decreased with the incorporation of AgNPs, and this was beneficial for food preservation. Especially, Ag@CS/PVA films could reduce the weight loss of strawberries and avoid microbial infection at 25 ± 1 °C and 50 ± 5% RH. Benefiting for good mechanical properties, antibacterial property, flexibility and high transparency, Ag@CS/PVA films showed its great potential in fruit storage and transportation application.