Antioxidant and antibacterial activities of chitosan/pullulan sustained-release coatings loaded with carvacrol microcapsules, and their application in fresh-cut green bell pepper preservation

The development of green, edible functional coating materials is crucial for addressing food safety issues. Traditional petroleum-based packaging materials, however, pose significant environmental pollution and resource waste due to their poor biodegradability. In this study, carvacrol (CA) encapsulated in β-cyclodextrin (β-CD) to form microcapsules (CMP) was integrated with a polysaccharide base (CTS/PUL) to create CP-CMP edible coatings. The physicochemical properties and microstructure of these films were evaluated using scanning electron microscopy, and fourier transform infrared spectroscopy. Successful incorporation of CMP into the CP coating via hydrogen bonding was indicated by changes in functional group vibrations, enhancing the barrier and thermal stability of the CP-CMP coating. The antioxidant capabilities of the coating, demonstrated by high DPPH (80.49 %) and ABTS (89.40 %) radical scavenging activities, were remarkable. Furthermore, it significantly inhibited Staphylococcus aureus and Escherichia coli. Applying the developed CP-CMP coating to fresh-cut green peppers extended shelf life from 8 days (control) to 12 days through dual actions: membrane-disrupting antimicrobial activity and integrated antioxidant functions that preserved color and retarded VC and chlorophyll degradation. Thus, the CP-CMP coating exhibits potent antioxidant and antibacterial properties, emerging as a promising alternative to traditional packaging materials. This innovative approach holds significant potential for reducing the environmental impact of white pollution.