Preparation and characterization of chitosan/bacterial cellulose nanofibers-based food packaging films blended with aqueous phase from purple passion fruit peel via hydrothermal carbonization

Purple passion fruit peel (PPFP) is a common biomass waste. Meanwhile, hydrothermal carbonization (HTC) is a common technology used for thermal conversion of biomass waste. Herein, the aqueous phase (AP) of PPFP was determined using HTC, and its properties were studied. Results indicated that AP exhibited strong antibacterial properties ( E. coli : 22.50 ± 0.80 mm, S. aureus : 23.28 ± 0.56 mm) and antioxidant capacity (EC 50 : 4.46 mg/mL). Chitosan (CS) and bacterial cellulose nanofibers (BCNFs) were used as the film matrix, and AP was introduced as an antimicrobial substance to develop AP/CSBC films. The interaction between the aqueous phase substances (APSs) and the CSBC film matrix was verified using Fourier transform infrared spectroscopy and X-ray diffraction analysis. The AP/CSBC films demonstrated excellent antibacterial and antioxidant activities. Blueberry preservation test showed that the AP/CSBC films can effectively extend the shelf-life of the fruit, indicating their potential as novel food packaging materials. This study present a method of high-value PPFP utilization and offers an effective approach to preparing biodegradable antibacterial food preservation films.