Construction and properties of antibacterial sanxan gum/gelatin pads loaded with ε-polylysine and application on bananas preservation.

This study aimed to prepare ε-polylysine (ε-PL)-loaded gelatin/sanxan gum (SG) composite aerogel pads via freeze-drying. Here, ε-PL functioned as both a crosslinking agent and an antibacterial component. Three formulations (G1S2, G1S1, G2S1) with different gelatin/SG mass ratios were fabricated. These aerogel pads were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA). The results showed that G2S1 had a high-water absorption rate and achieved the highest encapsulation efficiency for ε-PL (75%). Additionally, it exhibited the strongest antibacterial activity against Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger. When applied to banana packaging, G2S1 greatly retarded fruit browning. It also preserved higher levels of total soluble solids and titratable acid, while inhibiting the activities of polyphenol oxidase and peroxidase as well as microbial proliferation. The aerogel pad showed efficient preservation through the antibacterial activity of ε-PL and its inherent ability to regulate the humidity of the storage environment. Our findings demonstrate that the G2S1 aerogel demonstrated favorable potential in enhancing the postharvest preservation effect of fruits, thereby providing a novel insight for the development of green preservation technologies.