Radiation preparation and antimicrobial activity of Poly(PVA/starch/Ag NPs) nanocomposite towards Penicillium digitatum on citrus fruits

The synthesis of Poly(PVA/St/Ag NPs) nanocomposite by using of gamma radiation was carried out. The progress of the reaction was examined by using different techniques such as Fourier transform infrared (FTIR), transmission electron microscopy (TEM), UV, XRD, and scanning electron microscopy (SEM). The FTIR show the successful preparation of the Poly(PVA/St/Ag NPs) nanocomposite by gamma radiation at a dose of 5 kGy. The TEM analysis displays the particle size distribution of Ag NPs and it is observed that the Ag NPs size was in the range of 21-30 nm. The SEM images show a good distribution of silver nanoparticles in the Poly(PVA/St/Ag NPs) nanocomposite. matrix, but with little agglomerations or aggregates observed on the surface of the Poly(PVA/St/Ag NPs) nanocomposite. The XRD analysis indicates that amorphous regions are enhanced in the Poly(PVA/St/Ag NPs) nanocomposite. The coating of Citrus fruits by of Poly(PVA/St/Ag NPs) nanocomposite showed better performance in inhibition of the growth of P. digitatum on citrus fruits than free Ag NPs at concentration of 30 ppm. The incorporation of Ag NPs in Poly(PVA/St/Ag NPs) nanocomposite has extremely obvious antifungal activities against P. digitatum due to the nanometer range of Ag NPs that can interact with P. digitatum surface and/or its core where it enters inside the cell, as a result, cellular metabolism is inhibited causing death of P. digitatum and subsequently exhibits antifungal activities.