Controlled release of chlorine dioxide from α-cyclodextrin complexes embedded in poly(lactic acid)/poly(butylene adipate-co-butylene terephthalate) films for sustainable food packaging

In this study, chlorine dioxide (ClO₂) was encapsulated within α-cyclodextrin (α-CD) via two approaches: in situ ClO₂ generation (EC) and effervescent tablets (ET). FTIR, XRD, TG-DTG, SEM, and water contact angle (WCA) analyses verified the successful formation of ClO₂/α-CD inclusion complexes and revealed distinct structural, thermal, and morphological differences between EC and ET. EC exhibited superior encapsulation efficiency (2.3% vs. 0.9% in ET), and slower ClO₂ release rates across varying storage temperatures, indicating stronger host - guest interactions and more robust structural integration. Kinetic analysis confirmed that ClO₂ release followed first-order and Ritger–Peppas models with a diffusion-controlled mechanism. The EC complex was incorporated into biodegradable PLA/PBAT composite films at varying concentrations (1–5%) to develop functional packaging materials. The incorporation of EC enhanced surface hydrophilicity but reduced tensile strength and light transmittance due to particle aggregation. At low loadings (1–3%), well-dispersed EC particles created a tortuous diffusion path and improved oxygen barrier properties. At 5% EC, excessive agglomeration induced microstructural defects and increased gas permeability, which was supported by microstructural observations. Grape preservation tests at 25 °C showed that PLA/PBAT/EC films effectively inhibited microbial spoilage and extended shelf life, despite a slight increase in mass loss related to higher water vapor permeability. In vitro antimicrobial evaluation against Rhizopus stolonifer further validated the concentration-dependent antibacterial activity of the films. These results highlight the potential of ClO₂/α-CD inclusion complexes for active food packaging applications. These results support the potential of EC-based ClO₂ complexes in active packaging systems for enhanced food preservation. • Developed dual-pathway α-CD encapsulation of chlorine dioxide (ClO₂). • Reaction-based EC complex showed higher loading and slower ClO₂ release than ET. • Incorporated EC into biodegradable PLA/PBAT films with tunable properties. • 3% EC films extended grape shelf life to 28 days by delaying microbial spoilage. • Demonstrated sustainable active packaging with controlled gaseous antimicrobial release.