Selectively encapsulated and dry-fabricated sandwich-type patch: CO2/ClO2 differentiated dual-gas release for multi-dimensional preservation of purple cabbage

Dry fabrication minimizes active gas loss during patch preparation. • Selective encapsulation enables differentiated CO₂/ClO₂ dual-gas release. • Centripetal moisture absorption triggers humidity-responsive gas generation. • Differential gas release extends fresh-cut cabbage shelf life to nine days. Premature CO₂/ClO₂ loss during wet-casting fabrication bottlenecks moisture-responsive packaging scale-up. To address this, this study prepared polyacrylate nanoparticles loaded with 85.8% sodium chlorite (200–400 nm) and alginate-gelatin films (tensile strength 9.7 MPa, water vapor permeability 19.9 g·mm/m 2 ·day·kPa). Dry nanoparticles, sodium bicarbonate, and citric acid were then loaded into alginate-gelatin pouches to create a sandwich patch, minimizing fabrication-stage gas loss. In humid environments, the polyacrylate core absorbed threefold more water than the film, driving unidirectional moisture influx. Selective encapsulation—sodium chlorite in polyacrylate/film bilayers versus sodium bicarbonate in film monolayer—enabled differentiated release: CO₂ peaked at 15% (v/v) within 12 h, while ClO₂ plateaued at 14.9 ppm ( w / v ) on day 3. Applied to fresh-cut purple cabbage, the differentially released gases suppressed respiration, extending shelf life from 3 to 9 days without visible wilting or decay. This dry-processing route enables multi-component gas differentiated release in smart packaging. Download: Download high-res image (88KB) Download: Download full-size image