Development of sodium alginate-based active packaging films reinforced with curcumin/β-cyclodextrin stabilized high internal phase Pickering emulsions for blueberry preservation.

Maintaining the safety and quality of minimally processed agricultural products is a significant challenge in modern food supply chains. This study developed multifunctional sodium alginate (SA)-based films incorporating high internal phase Pickering emulsions (HIPPEs) stabilized by curcumin/β-cyclodextrin inclusion complexes (CUR/β-CD). The HIPPEs demonstrated excellent colloidal stability (>21 days) with a mean droplet diameter of 12.76 ± 0.32 μm. Through solvent casting, HIPPEs were uniformly integrated into SA matrices (0.5-2 % w/w). Based on a comprehensive characterization of the films, the optimum concentration of 1.5 % for doping with HIPPEs was determined. The SA/HIPPEs1.5 films exhibited excellent tensile strength (14.21 MPa), elongation at break (26.28 %), and adequate water vapor (6.5 × 10 g/(m·s·Pa)) and oxygen permeability (1.06 × 10 g/m·s). Furthermore, they demonstrated dual antimicrobial-antioxidant functionality, with inhibition zones of 19.30 ± 0.70 mm (Staphylococcus aureus) and 20.53 ± 0.40 mm (Escherichia coli), along with 70.63 % DPPH radical scavenging activity. Compared to polyethylene packaging, SA/HIPPEs1.5 films effectively preserved blueberry quality at 25 °C for 18 days, showing lower weight loss (30.6 % vs. 42.2 %) and a favorable pH (3.43 vs. 4.22). These findings support the potential of SA/HIPPEs composite films as an effective active packaging solution for extending blueberry shelf life.