Study on the Fruit Preservation Potential of Pectin–Sodium Alginate–Nanocellulose–Rutin-Based Aerogel Functional Materials with High Compressive Properties

In this study, a dual-crosslinked Ca2+-SA/LMCP hydrogel network with both elasticity and toughness was constructed via Ca2+ crosslinking of low-methoxyl citrus pectin (LMCP) and sodium alginate (SA). Cellulose Nanofiber (CNF) was then incorporated as a physical reinforcing phase, interacting with the Ca2+-SA/LMCP network through hydrogen bonding and physical entanglement to further enhance the physical framework strength. Finally, rutin (RTN) was loaded into this system as an antibacterial agent, and the system was freeze-dried to fabricate antibacterial aerogel preservation sheets with an ionically crosslinked and physically entangled dual-network structure composed of Ca2+-SA, LMCP, and CNF. The effects of RTN concentration on the porous structure and mechanical properties of the composite aerogels were investigated. The surface micromorphology, functional groups, thermal behavior, and crystalline structure of the LMCP/SA/CNF/RTN composite aerogels were characterized in detail by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and X-Ray Diffraction (XRD). Notably, a well-developed porous structure was observed in the composite aerogel when the Ca2+ concentration was 15 mmol/L, pH was 4, the LMCP/SA mass ratio was 1:1, and the CNF concentration was 15 mg/mL. The antibacterial activity, loading capacity, and mechanical properties of the aerogels were further verified through mechanical tests, swelling tests, and antibacterial assays. The experimental results showed that the maximum compressive modulus of the LMCP/SA/CNF aerogel was 6.57 MPa, and the compressive stress was 1.313 MPa. The swelling ratio of the LMCP/SA/CNF/RTN composite aerogel in PBS reached 2246%. Antibacterial assays revealed that composite aerogels with different RTN concentrations all exhibited inhibitory effects against Staphylococcus aureus; notably, the inhibition zone diameter of the aerogel containing 0.5 g RTN reached 9.8 mm. In summary, the development of this innovative antibacterial aerogel material demonstrates its application potential as a packaging cushioning material, providing new technical insights for this field.