An innovative sodium carboxymethyl cellulose-based chlorine dioxide-releasing hydrogel incorporating α-cyclodextrin...

Unlike all previously reported chlorine dioxide (ClO₂)-releasing hydrogels, which rely on the in situ reaction between sodium chlorite and acid, this work presents an innovative hydrogel based on sodium carboxymethyl cellulose (CMC) and α-cyclodextrin (α-CD) inclusion complexes containing ClO₂ molecules. The hydrogel is stable at 4 °C and continuously releases gaseous ClO₂ at 25 °C. In vitro experiments showed that fumigation with 2.0 g and 1.5 g of hydrogels completely inhibited the growth of Aspergillus niger and Penicillium on Potato Dextrose Agar (PDA), respectively. Fumigation with 2.0 g of hydrogel reduced the A. niger-induced incidence of strawberries on day 4 from 100.00 % (control) to 19.98 %. Meanwhile, fumigation with 1.5 g of hydrogel reduced the Penicillium-induced incidence of citrus from 98.78 % (control) to 0.00 % on day 2. In addition, the hydrogel effectively maintained fruit qualities such as weight, firmness, total soluble solid content (TSS), titratable acidity (TA), the TSS/TA ratio, ascorbic acid (ASA), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate, color, and sensory indicators during storage. Notably, strawberries and oranges inoculated with respective fungal strains exhibited a four-day extension in shelf life after hydrogel treatment. Moreover, the hydrogel has the distinct advantage of not requiring acid activation, thereby improving stability, enhancing safety, and offering greater convenience. These attributes collectively enable it to outperform many previously reported sodium chlorite-based active packaging systems in food industry. As an eco-friendly and biodegradable novel material, it holds significant potential for maintaining food quality and extending shelf life.