Quenching and awakening: A demethylated lignin composite enabling dual antioxidant pathways for extending the preservation period of blueberry.

Effective food preservation is essential for reducing post-harvest losses and maintaining the quality of agricultural produce. To address shortcomings such as limited antibacterial activity, singular antioxidant mechanism, and insufficient oxygen barrier performance, this study presents a multifunctional composite preservation system (MSDE) based on demethylated lignin and porous silica. Demethylation increased phenolic hydroxyl active sites by 188.6%, exhibiting excellent antibacterial activity. MSDE exhibits inertness toward scavenging O2-, while demonstrating remarkable scavenging efficiency for H2O2 and •OH. Notably, porous silica's electron-rich oxygen vacancies transfer electrons to demethylated lignin via covalent Si-O-C heterointerfaces, synergistically driving GSSG reduction to regenerate glutathione, indicating potential applicability in plant stress resistance. Through interfacial densification and gas adsorption, MSDE induced a localized "gas maze" effect, reducing oxygen permeability by 86.04%. The composite films loaded with MSDE effectively extended the preservation period of blueberries for 7 days while preserving key nutrients like vitamin C and anthocyanins, providing an innovative strategy for the design of multifunctional food preservation materials.