Lagerstroemia speciosa fruit-mediated synthesis of silver nanoparticles and its application as filler in agar based nanocomposite films for antimicrobial food packaging

Agar based nanocomposite films were developed by incorporation of silver nanoparticles (AgNPs) as filler. The AgNPs were synthesized using aqueous fruit extract of Lagerstroemia speciosa, an abundantly available medicinal plant in North-Eastern part of India. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM) analysis. TEM results showed that most of the particles were hexagonal in shape with size range of 32-62 nm. Incorporation of AgNPs improved the antimicrobial property, thermal stability, elongation at break and appearance of the composite films, whereas tensile strength (TS) decreased. The FTIR analysis of the films showed that the AgNPs had good compatibility with agar matrix. The orange-brown colour of the composite films may help to protect wrapped (packed) food products from UV rays. The composite films showed good antibacterial activity against Gram-negative foodborne pathogen Aeromonas hydrophilla, and may have potential for food packaging applications.