Influence of chitosan-capped quercetin nanoparticles on chitosan/poly(vinyl) alcohol multifunctional films: A sustainable approach for bread preservation.

Food packaging industries are growing to meet consumer demand and prevent pollution by adopting significant biopolymer advancements. Therefore, this study aimed to develop functionally active chitosan (CS)/polyvinyl alcohol (PVA)-based biopolymer films and evaluate the effect of Justicia Adhatoda extract (JAE), pure quercetin (Q), and CS-capped quercetin nanoparticles ((Q)CS NPs) on sustainable bread packaging. CS was successfully loaded onto (Q) by the one-pot method, which was confirmed by light absorption spectroscopy (UV), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The fabricated films were examined using different analytical techniques. FTIR and XRD patterns confirmed that the CS/PVA matrix had molecular interactions through hydrogen bonds with JAE, (Q), and (Q)CS NPs. SEM micrograms revealed a uniform distribution and denser surface with small aggregations by adding (Q)CS NPs. The (Q)CS NPs added CPE(Q)CS nanocomposite exhibited excellent UV light shielding (99.99 % UV-A and UV-B blocking), water resistance ability (contact angle:99.44°, WVP:3.68×10-7 gh-1m-1Pa-1), and oxygen (0.614×10-6gh-1 m-1 atm-1) barrier properties. Adding (Q)CS NPs enhanced the antimicrobial properties of CPE(Q)CS against foodborne microbes (E. coli:15.45 mm, P. aeruginosa:14.50 mm, B. subtilis:14.25 mm, S. aureus:13.52 mm, and C. albicans:15.16 mm). In addition, incorporating (Q)CS NPs, increased the shelf life of bread compared to unpacked and polyethylene-packed bread samples.