Effect of biodegradable chitosan–rice‐starch nanocomposite films on post‐harvest quality of stored peach fruit

A nanocomposite degradable chitosan–rice‐starch (CRS) film was prepared by incorporation of commercial (Comm.) and microbial synthesized silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) using a solvent‐casting technique. The prepared films were characterized for thickness, surface color measurement, transparency, presence of crystalline features, surface topography, and surface elemental composition. The fabricated nanocomposite films were evaluated for antimicrobial activity and were observed to curb the growth of test Gram‐negative (Escherichia coli) and Gram‐positive (Staphylococcus aureus) microorganisms in an in vitro media Petri plate study. The screened nanocomposite films were then tested to improve the shelf life of peach fruits (cv. Shan‐i‐Punjab) in packaging. The nanocomposite films with incorporated NPs decreased the overall surface microbial load and enhanced the shelf life of packed peach fruits as compared to unpackaged and packaged fruits with control film. The lowest percentage loss in weight (4.75%) was recorded in peach fruits packaged with film incorporated with Comm. Ag NPs. The lowest change in diameter (4.25–4.05 cm) and the highest ascorbic acid content (0.51 mg/g) were found in peach fruits packaged with films incorporated with Comm. ZnO NPs. The lowest percent (9.6%) increase in total soluble solids was observed for fruits packaged with films incorporated with Comm. AgNPs. The microbial counts on the surface of the fruit was highest for the unpackaged control treatment and lowest for fruits packaged with Comm. Ag NPs. SEM study of the surface of the peaches showed the presence and adherence of microbial cells (bacteria, yeast, and fungi) on the trichomes and the fruit surface.