Polysaccharide isolated from Rosa roxburghii Tratt fruit as a stabilizing and reducing agent for the synthesis of silver nanoparticles: antibacterial and preservative properties

The fruit of Rosa roxburghii Tratt can be consumed as food or juice. However, the pomace of this fruit is typically regarded as waste, the application of which may create opportunities to produce new and valuable by-products. Here, we demonstrated that the properties (high water solubility and uronic acid content) of an acidic polysaccharide (RTFP-3) isolated from Rosa roxburghii Tratt fruit can facilitate the reduction of AgNO 3 into Ag nanoparticle composites (RP3-AgNPs) using a one-step, eco-friendly process. The structural and functional properties of synthesized RP3-AgNPs conjugates were characterized using spectroscopic, physical and antimicrobial susceptibility testing. The UV–Visible spectra of the RP3-AgNPs showed the surface resonance peak at around 415 nm. The fcc crystalline nature was identified by X-ray diffraction, and the size from 24.5 to 83.2 nm was identified by particle size analysis. Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and thermal gravimetric analysis showed that the reducing process of AgNPs was mild and could preserve the original nature of the RTFP-3. The RP3-AgNPs composites exhibited an excellent antimicrobial ability against Staphylococcus aureus and Escherichia coli compared with RTFP-3. Compared with chitosan (control), the application of RP3-AgNPs to cherry tomatoes showed similar preservative effects. The preparation of the RP3-AgNPs using RTFP-3 may provide a green and sustainable strategy for the development of antimicrobial products.