Sustainable cellulose acetate beads impregnated with eugenol, thymol, β-citronellol, and their mixtures via supercritical carbon dioxide for microbial and pest insect control.

Post-harvest losses of legumes caused by microbial contamination and pest insects represent a major challenge for food security and sustainable storage systems. In this study, biodegradable and bio-based cellulose acetate beads (CAB) were developed as functional materials for bean protection using an environmentally benign supercritical impregnation process. Eugenol, thymol, β-citronellol, and their mixtures were incorporated into CAB, achieving loadings of up to 7.5 wt% within a 3 h process. Impregnation resulted in a pronounced reduction in average pore size, from approximately 0.5 to 0.2 μm, indicating structural modification of the polymer matrix. FTIR and combined DSC/TGA analyses confirmed successful incorporation of the bioactive compounds and their interactions with cellulose acetate. The resulting materials enabled controlled release of active compounds in air at 25 °C for more than one month, matching realistic storage conditions. Biological evaluations demonstrated effective antimicrobial activity and significant deterrent effects against the dried bean beetle. Overall, this work provides new insights into composition-structure-bioactivity relationships in carbohydrate-based materials and demonstrates the potential of supercritical CO2-assisted impregnation as a sustainable strategy for developing functional materials for food storage applications.