Effects of chitosan/eugenol-loaded IRMOF-3 nanoparticles composite films on reactive oxygen species metabolism and microbial community dynamics in postharvest strawberries

The market value of strawberries is considerably impacted by quality deterioration and senescence during postharvest storage. In the study, the effect of isoreticular metal-organic skeleton (IRMOF-3) nanoparticles loaded with eugenol/chitosan-based active packaging film on the metabolism of reactive oxygen species (ROS) and the change rule of the structure of the microbial community in strawberries inoculated with strawberries spoilage bacteria ( Botrytis cinerea ) during the storage period was investigated. The results demonstrated that composite film contribute to the sustenance of reduced hydrogen peroxide and superoxide anion concentrations and the suppression of malondialdehyde accumulation, in contrast to the control group. This investigation revealed that the composite film significantly bolstered the antioxidant enzyme activities and disease resistance-related enzyme activities of strawberries, encompassing polyphenol oxidase, peroxidase, superoxide dismutase (SOD), and catalase (CAT). Moreover, the transcription levels of SOD and CAT genes were notably elevated in strawberries packed within the composite films. Besides, the composite film had an inhibitory effect on pathogenic bacterial genera ( Ralstonia , Sphingomonas , and Erwinia ) and fungal genera ( Botrytis cinerea ) that cause strawberries spoilage and a delayed decline in bacterial genera (unidentified_ Chloroplast and Chryseobacterium ) and fungal genera ( Rhodotorula ) that are biocontrols of strawberries postharvest diseases. Therefore, this study provides novel perspectives on the mechanisms underlying the preservation of fruits and vegetables, focusing on alterations in ROS metabolism and microbiota composition during storage.