Carboxymethyl cellulose/polyvinyl alcohol aerogel incorporating cinnamaldehyde-citronellal synergy for controlling green mold decay in citrus fruit

The citrus green mold caused by Penicillium digitatum is a wound-mediated disease considered the main cause of post-harvest citrus fruit spoilage. In this study, an antifungal composite aerogel based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) was prepared and used to controlling green mold in citrus fruit with a combination of cinnamaldehyde and citronellal (CC). Characterization revealed that the CMC/PVA aerogel had a three-dimensional porous structure, and hydrogen-bond interactions existed between -C O groups of CMC and -OH groups of PVA. The composite aerogels had lower porosity, higher density and lower hygroscopicity performance than raw CMC aerogels. When loaded with CC (4:1, v/v), the aerogel enabled continuous release to fifteen days, with its maximal release rate on the second day. The release profiles of the CMC/PVA-CC were fitted well by the Korsmeyer–Peppas model and the release behavior was governed by Fickian diffusion. In vitro and in vivo tests showed that these aerogels inhibited P. digitatum growth in a concentration-dependent manner. Moreover, CMC/PVA composite aerogels loaded with 0.01 μL L −1 CC suppressed postharvest green mold decay in citrus fruit, demonstrating efficacy comparable to that of the 0.025 % prochloraz, while maintaining fruit quality after storage of 30 d. These results indicated that CC-loaded CMC/PVA composite aerogels can serve as a sustained release and eco-friendly alternative to conventional chemical fungicides for managing postharvest diseases in citrus fruit.