Incorporation of Schizochytrium limacinum oil-based pickering emulsion in chitosan active composite films for strawberry preservation.

Abstract

Bioactive composite films have emerged as promising candidates for sustainable food packaging due to their multifunctional performance and environmental compatibility. In this study, a novel active packaging film (SL/CS) was developed by incorporating Schizochytrium limacinum (SL) oil-based Pickering emulsions, stabilized by soy protein isolate (SPI), into a chitosan (CS) matrix via a casting method. SL oil is a marine-derived bioactive lipid rich in polyunsaturated fatty acids and antioxidant carotenoids. Its incorporation into the CS film increased the surface contact angle to 91.79° and reduced the water vapor permeability (WVP) to 1.354 × 10-12 g·cm/cm2·s·Pa, indicating improved moisture barrier capacity. Additionally, UV-vis analysis confirmed that the SL-10 % film effectively blocked UV light across 200-380 nm. The DPPH radical scavenging activity of the SL/CS film was 89.67 % at 10 % SL oil loading. Antibacterial assays revealed maximum inhibition zone diameters of 28.84 mm for S. aureus and 14.90 mm for E. coli, with corresponding growth inhibition rates reaching 95.19 % and 88.19 %. In strawberry preservation experiments, the SL/CS film extended the shelf life of strawberries by reducing weight loss and mitigating the loss of firmness and titratable acidity during storage. Therefore, the results of this work support the potential of SL/CS films as a natural and effective packaging material for postharvest fruit preservation.