Biosynthesis of metallic nanoparticles using mulberry fruit (Morus alba L.) extract for the preparation of antimicrobial nanocellulose film

Aqueous extract of mulberry (Morus alba L.) fruit was used as a bio-functional reducing material for green synthesis of silver (Ag), copper (Cu) and palladium (Pd) metallic nanoparticles (NPs). The formation of NPs was monitored visually and characterized by UV-Vis spectroscopy and the morphology and size of the as-prepared NP were evaluated with TEM and dynamic light scattering, respectively. The synthesized Ag, Cu, and PdNPs were found to be spherical and non-regular in shape with average particle sizes ranging from 80 to150 nm (AgNPs), 50 to 200 nm (CuNPs) and 50 to 100 nm (PdNPs). The results represented that CuNP had a superior antibacterial activity against Escherichia coli O157:H7 and Listeria monocytogenes as compared to AgNPs and PdNPs. Furthermore, ex situ incorporation of NPs into bacterial nanocellulose (BNC) film made BNC with elevated antimicrobial capability on both tested microorganisms. NP-BNC films revealed different NP release pattern into food simulants depending on the type of NPs and simulants. The order of NP release rate from BNC in all food simulants (10, 50, and 95% ethanol) was as follows: CuNP>PdNP>AgNP. Accordingly, the fabricated BNC/NP nanocomposite film might be useful as a novel biomaterial to combat pathogens on food commodity.