Antibacterial properties of sweeping-frequency ultrasonic modified xanthan gum@ZnO composite film and application in grape preservation

This study investigated the antibacterial mechanism and preservation efficacy of the XG₂₅/ZnO₁₀ composite film against E. coli and S. aureus. The film, containing sweeping-frequency ultrasonic (SFU) modified xanthan gum (XG) and nano zinc oxide (ZnO), showed significant antibacterial activity. Multiple analyses revealed a synergistic mechanism between the components. Simulation confirmed SFU generated the uniform acoustic field, enhancing process efficiency. In a 21-day refrigerated storage test, the composite film effectively maintained grape quality. It significantly improved retention rates of soluble solids (66.24%), total phenols (66.01%), and ascorbic acid (58.37%) compared to control. The film maintained microbial load at 3.94 log CFU·g^-1, substantially lower than traditional polyvinyl chloride packaging (6.23 log CFU·g^-1).