Electrospinning titanium dioxide/thymol/pullulan/polyvinyl alcohol nanofibers with ethylene scavenging and antibacterial properties for kiwifruit preservation

Abstract Kiwifruit is prone to rapid softening due to ethylene accumulation and is highly susceptible to microbial infection and decay. To address these two major challenges, a multifunctional film was developed via electrospinning using polyvinyl alcohol (PVA) and pullulan (PUL) as a composite polymer matrix, and incorporated with titanium dioxide (TiO2) nanoparticles and thymol (THY) as photocatalyst and natural antimicrobial agent, respectively. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed the uniform dispersion of TiO2 nanoparticles within the fibers without obvious aggregation. The X-ray diffraction and Fourier transform infrared results verified the successful integration of anatase TiO2 and THY into the nanofiber film. The nanofiber film nearly completely degraded ethylene (200×10−6) within 4 h under irradiation, corresponding to a degradation rate of 12.5 µL/(g·h). Furthermore, the nanofiber film exhibited 100% antibacterial efficiency against Escherichia coli, Staphylococcus aureus, and Botryosphaeria. Compared with PUL/PVA film, the TiO2/THY/PUL/PVA composite film exhibited enhanced thermal stability, ultraviolet absorption capacity, and mechanical strength. Under 4 °C storage condition, the active packaging film extended the shelf life of kiwifruit to more than 35 d, effectively maintained fruit firmness and color, delayed the decline in total soluble solids, vitamin C, and anthocyanins, decelerated weight loss and malondialdehyde accumulation, and markedly suppressed microbial infection. This study provides an effective strategy for developing active packaging materials with ethylene degradation and antimicrobial functions, offering considerable potential for advancing postharvest preservation technologies for kiwifruit and other climacteric fruits.