Application of Nanocomposites of Chitosan and Neptune Grass- Biosynthesized Selenium Nanoparticles as Edible Coatings for Preserving Citrus Fruits

Abstract

Nanobiotechnological techniques can be used to effectively solve the problems associated with contamination and spoilage of food products. Rapid and environment-friendly approaches for synthesis of nanocomposites consisting of chitosan nanoparticles (Cht), neptune grass extract ‘Posidonia oceanica” (NG) and selenium nanoparticles generated by NG (SeNPs) were envisaged, and their use as potential antifungal and edible coatings (ECs) and biopreservatives of citrus (orange) fruits was investigated. SeNPs were biosynthesized using NG, and the conjugation between SeNPs and Cht nanocomposites was carried out. Characterization techniques such as FTIR screening, structure and optical analysis of biosynthesized nanomaterials were used. Antifungal activity of biosynthesized nanomaterials against Penicillium digitatum fungal isolates was determined. The potential antifungal activities of nanomaterials were utilized in making ECs for the preservation of oranges (Citrus × tangelo). Biosynthesis of SeNPs using NG was highly successful, with an average diameter of 13.82 nm; NG/SeNPs showed homogenous spherical structures with even distribution. Average diameter of biosynthesized Cht/NG/SeNPs was found to be 171.55 nm. The role of biochemical compounds in the synthesis and reaction of nanomaterials is evident from their infrared analysis. The antifungal activities of nanomaterials were seen against all of the tested strains of fungi. In particular, for the cases of P. digitatum isolates, all agents and nanocomposites possessed good fungicidal capacities; however, the highest was observed in Cht/NG/SeNPs nanocomposites, which performed way better than the fungicidal efficacy of traditional fungicides. Symptoms of green mold were eradicated completely after applying Cht/NG/SeNPs nanocomposite-based ECs on an infected orange fruit. This study can contribute toward future utilization of biosynthesized compounds for producing edible coatings and antifungal nanocomposites on citrus fruits.