A starch-based composite film with dual-modality essential oil controlled-release for perishable fruit preservation

Starch-based active packaging films with slow-release essential oils face significant challenges due to poor release kinetics, making the development of controlled-release systems imperative. In the process of improving the controlled-release system, the simultaneous enhancement of various performance indicators of starch films is still emphasized, especially the trade-offing between good physical properties and long-lasting bioactivity. Here, a pectin-nanolignin-stabilized citrus essential oil (CEO) Pickering emulsion (PLCPE) was prepared and used to activate starch matrix, aiming to develop a composite film with long-lasting slow-release and humidity-response release of CEO. PLCPE has good compatibility with starch film, which can be evenly dispersed in starch matrix and fill the gaps between starch molecules, and enhance the cross-linking and entanglement between molecules through hydrogen bonds. PLCPE activates starch film to provide CEO long-lasting slow-release, antioxidant, antibacterial, and UV resistance, while enhancing their mechanical properties, water contact angle, and water vapor/oxygen barrier, achieving a trade-off between good physical properties and long-lasting bioactivity. Interestingly, elevated humidity can weaken the pectin intermolecular chain interactions of the PLCPE continuous phase and begin to break, so it can be used as a humidity-responsive switch to modulate the release of CEO in the film through humidity changes. They significantly extend the shelf life of perishable fruits when used as packaging materials and are also reliably biosafe and naturally degradable without burdening the human body or the environment. This research is expected to further advance the development of starch-based intelligent active packaging, providing new opportunities to reduce food waste and protect the environment.