Characterization and antimicrobial activity of a chitosan-selenium nanocomposite biosynthesized using Posidonia oceanica

Nanobiotechnological approaches can provide effective solutions for overcoming food products' contamination and spoilage. The development of rapid and eco-friendly approaches for synthesizing nanocomposites from chitosan nanoparticles (Cht), Neptune grass “Posidonia oceanica” extract (NG), and NG-mediated selenium nanoparticles (SeNPs) was targeted, with their investigation as potential antimicrobial, antioxidant, and biopreservatives of fresh chicken fillets. SeNPs were biosynthesized with NG, and their conjugates with Cht were composited. Characterization approaches, including infrared analysis, physiognomic analysis, and electron microscopy of synthesized nanomaterials and composites, were applied. The nanomaterials' antibacterial properties were assessed against Staphylococcus aureus, Salmonella typhimurium, and Escherichia coli qualitatively, quantitatively, and with ultrastructure imaging. The antimicrobial and antioxidant potentialities of nanomaterials were employed for preserving chicken fillets, and the sensorial and microbiological parameters were assessed for coated fillets. SeNPs were effectively biosynthesized by NG, with mean diameters of 12.41 nm; the NG/SeNPs had homogenous spherical shapes with good distribution. The prepared Cht/NG/SeNPs nanoconjugates had a mean diameter of 164.61 nm, semi-spherical or smooth structures, and charges of +21.5 mV. The infrared analyses revealed the involvement of biochemical groups in nanomaterial biosynthesis and interactions. The antibacterial actions of nanomaterials were proven against the entire challenged strains; Cht/NG/SeNPs was the most active agent, and Salmonella typhimurium was the most susceptible bacteria. Scanning micrographs of Cht/NG/SeNPs-treated Staphylococcus aureus and Salmonella typhimurium indicate the severe time-dependent destruction of bacterial cells within 8 h of exposure. The antioxidant potentiality of Cht/NG/SeNPs was the highest (91.36%), followed by NG/SeNPs (79.45%). The chicken fillets' coating with Cht, NG, NG/SeNPs, and Cht/NG/SeNPs resulted in a remarkable reduction in microbial group count and raised the sensorial attributes of coated fillets after 14 days of cold storage, with increased potentialities in the order: Cht/NG/SeNPs > NG/SeNPs > NG > Cht > control. The inventive, facile biosynthesis of Cht, NG, and SeNPs could provide effective antimicrobial and antioxidant nanocomposites for prospective applications in food biopreservation.