Chitosan/Polyvinyl-alcohol Film Bio-composite loaded by Caesalpinea sappan extract with enhanced super bug antimicrobial properties for food packaging application

The improvement of the antibacterial properties of chitosan (CS)/polyvinyl alcohol (PVA)-based bio-composites is widely pursued because it holds great promise for a variety of sustainable food packaging applications. This study reports the improvement of the antibacterial properties of CS/PVA by loading C. sappan extract (CSE), a natural bioactive component, against Escherichia coli (E. coli), Staphylococcus aureus (SA), and methicillin-resistant Staphylococcus aureus (MRSA). The effect of CSE on the physical and mechanical properties of the CS/PVA film was also investigated. Notably, the CSE-loaded bio-composites exhibited selectivity for targeting gram-positive bacteria and significantly improved the inhibition zone, reaching 17.4 mm, 29.5 mm (4%), 23.9 mm, and 41.6 mm (6%) for SA and MRSA, respectively. The CS/PVA/CSE film, as a packaging sheet, is also able to preserve bread for up to 1 month by repelling the growth of microorganisms. The addition of CSE to the bio-composite film slightly affects its biodegradability and ultraviolet barrier properties. The CSE added to the CS/PVA bio-composite film acts as a plasticizer, improving its mechanical properties. Hence, CSE-loaded CS/PVA bio-composite films could be prospective eco-friendly bioactive packaging candidates for sustainable food preservation.