Green active packaging: pH‑modulated pectin-based composite membranes incorporated with ellagic acid/γ‑cyclodextrin for postharvest blueberry (Vaccinium corymbosum L.) preservation

The development of eco-friendly, biodegradable, and multifunctional bio-based composite membranes serves as a promising strategy to safeguard global food security. In this study, we successfully synthesized the ellagic acid/γ-cyclodextrin (EA/γ-CD) inclusion complex, as well as six pectin-based edible composite membranes loaded with this inclusion complex and conducted comprehensive physicochemical characterization on the prepared materials. The results showed that the EA/γ-CD inclusion complex achieved a loading capacity of 9.02% and an encapsulation efficiency of 87.19%, and complexation with γ-CD increased the water solubility of EA by approximately 3.6 times. Zeta potential and particle size analysis confirmed that cyclic pH treatment modulated the colloidal stability of the composites in a pectin-type-dependent manner. Release kinetics indicated that, unlike the free EA-loaded membrane which exhibited slow release that plateaued at a low cumulative level, EA/γ-CD/H(pH) delivered rapid and sufficient EA release triggered by humidity, with a cumulative release rate reaching 93.33%. Meanwhile, EA/γ-CD/H(pH) composite membrane demonstrated superior performance in light transmittance, water solubility, water vapor permeability, wettability, degradability, antifungal activity, and antioxidant capacity. The composite membrane also exhibited excellent preservation efficacy for fresh postharvest blueberries. Furthermore, analysis via HS-GC-IMS revealed that EA/γ-CD/H(pH) composite membrane can positively maintain the volatile flavor compounds of postharvest blueberries. ( E )-2-hexen-1-al- D had the highest variable VIP score, and can be considered the most reliable biomarker for distinguishing blueberry samples packaged with the EA/γ-CD/H(pH) edible food packaging membrane.