Bacterial cellulose-based multifunctional films modified with natural Sapindus saponin: a sustainable food packaging...

Escalating environmental concerns over plastic packaging have prompted extensive researches into renewable bio-based alternatives. In this study, bacterial cellulose (BC) films modified with natural Sapindus saponin (SS) and gelatin were developed as multifunctional active packaging materials for fruit preservation. SS and gelatin gave the composite a denser and more stable structure via the formation of covalent crosslinking, thereby strengthening the mechanical properties of the bio-based films (BFs). The tensile stress of the designed film (BF3) was 28.21 MPa, which was 89.93% greater than that of the BC film. Compared with the control, the BFs had better thermal stability and greater barrier properties, coupled with good natural affinity. Additionally, owing to the presence of SS, the BF3 showed remarkable ultraviolet-blocking capacity (92.24% UVA and 99.71% UVB shielding rates), antioxidant activity (68.47% DPPH and 74.38% ABTS scavenging activities), and anti-bacterial property (Escherichia coli, 6.4 mm; Staphylococcus aureus, 22.8 mm), which corresponded to the excellent freshness preservation ability. The fresh blueberries packaged with BF3 had less weight loss, reduced postharvest decay, and delayed softening, thus achieving a longer shelf life. In summary, BFs have a promising application prospect as a sustainable and effective packaging material for fruit preservation.