Sustainable chitosan/polyvinyl alcohol composite film integrated with sulfur-modified montmorillonite for active food packaging applications

Sulfur-functionalized montmorillonite (S-MMT), which has strong antioxidant and antibacterial activities, was prepared by forming a sulfur-amine complex using ethylenediamine (EDA). S-MMT was added to the chitosan/polyvinyl alcohol (Chi/PVA) blend polymer to develop an active food packaging film. The composite film, especially 4 wt% S-MMT-added Chi/PVA film (Chi/PVA/S-MMT^4%), showed significant increases in tensile strength (∼25.1 %), elongation at the break (∼94.1 %), and UV-blocking ability (98.2 % UV-A and 100 % UV-B) compared to the neat Chi/PVA film. The Chi/PVA/S-MMT^4% film also exhibited remarkable antioxidant properties (100 % ABTS and 65.4 % DPPH scavenging activity) and potent antibacterial activity (stopped the growth of L. monocytogenes and E. coli). Chicken packaged in the composite film showed a significant reduction in quality changes, including appearance, pH, thiobarbituric acid reactive substances (TBARS), and total viable colonies (TVC) over 20 days of storage. Multifunctional Chi/PVA/S-MMT films have high potential in active food packaging applications.