Pullulan/PVA based film incorporated with cinnamon essential oil submicron Pickering emulsion stabilized by carboxymethyl chitosan modified with phenolic acids: Preparation and application on mango preservation

Phenolic acids grafting enhanced the DPPH/ABTS + radical scavenging activity of CMCS. • CEO submicron emulsions stabilized by CMCS-g-GA showed 60-day storage stability. • Films loaded with CEO submicron emulsions extended shelf life of mango by 5–10 days. Food packaging films with antibacterial and antioxidant properties play a crucial role in the postharvest preservation of fruits. In this study, pullulan/polyvinyl alcohol (PUL/PVA) composite films incorporated with cinnamon essential oil (CEO) Pickering emulsions with submicron droplets stabilized by carboxymethyl chitosan modified with gallic acid (CMCS-g-GA) were fabricated for mango preservation. Antioxidant assays revealed that CMCS-g-GA at 50.0 μg/mL exhibited DPPH and ABTS + radical scavenging rates of 91.06% and 93.40%, respectively, representing 8.46-fold and 10.37-fold increases compared to those of unmodified CMCS. The prepared CEO emulsion, consisting of submicron droplets with an average size of approximately 704 nm, exhibited excellent storage and centrifugal stability, showing no phase separation after 60 days of storage or centrifugation at 2000 rpm for 2.5 h. Incorporation of the CEO emulsion enhanced the antibacterial and barrier properties of composite films (PP/CG-CEO), with the PP/CG-CEO20 film exhibiting the lowest water vapor permeability (3.61 × 10 −10  g/m·s·Pa) and oxygen permeability (3.53 × 10 −10  g/m∙s∙Pa). Room-temperature storage experiments demonstrated that the PP/CG-CEO coating films exerted an effective preservative effect on mangoes, maintaining the postharvest quality, enhancing antioxidant enzyme activity, delaying yellowing, and retarding the respiratory peak. These results demonstrated that the multifunctional cinnamon essential oil Pickering emulsion films have practical potential as eco-friendly packaging for postharvest fruit preservation. Download: Download high-res image (158KB) Download: Download full-size image