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

Demethylation elevates phenolic hydroxyl active sites by 188.6%. • Dual antioxidant pathways: radical scavenging and glutathione regeneration • The composite film shows an 86.04% reduction in O 2 permeability. • The composite film extends shelf life by 7 days and improves nutrient preservation. 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 O 2 − , while demonstrating remarkable scavenging efficiency for H 2 O 2 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.