In situ synthesis of silver nanoparticles in pectin matrix using gamma irradiation for the preparation of antibacterial pectin/silver nanoparticles composite films

The present study reports in situ synthesis of silver nanoparticles (AgNPs) in pectin matrix using gamma-irradiation at 2.5 and 5 kGy and preparation of antibacterial pectin-based nanocomposite films. The FE-SEM micrographs showed that the neat pectin film was smooth but became a little rough after forming AgNPs in the pectin films. The UV-visible spectroscopy analysis exhibited a surface plasmon resonance (SPR) band about 430 nm confirming the formation of AgNPs in the pectin films. The Hunter color values of nanocomposite film changed after the formation of AgNPs. FTIR and thermogravemetric analysis results revealed no structural and thermal stability changes in the pectin films after the synthesis of AgNPs by gamma-irradiation. However, mechanical properties and water vapor permeability of the composite films improved after AgNPs synthesis. The pectin-AgNPs nanocomposite films exhibited potent antibacterial activity against Escherichia coli and Salmonella Typhimurium. The developed antibacterial pectin-based nanocomposite films incorporated with AgNPs using gamma-irradiation have a potential to increase the shelf life of packaged food.