Effect of ozone treatment on the decay and cell wall metabolism during the postharvest storage of cantaloupe

Cantaloupe is a popular summer fruit with immense market potential in China. However, the cantaloupe fruits generally soften rapidly after harvest, which dramatically reduces their economic value. The ozone treatment has been found to be effective in delaying the softening of cantaloupe fruit. The results indicated that ozone treatment significantly inhibited the mycelial growth of Fusarium hypha. The ozone treatment was able to delay the decline of total soluble solids, lower the respiration rate, and maintain the fruit's firmness without damaging fruit quality. The study also indicated that the activity and gene expression of cell wall degrading enzymes such as polygalacturonase (PG), pectin methylesterase (PME), f-galactosidase (f-gal), cellulose (Cx), and alpha-L-arabinofuranosidase (alpha-L-Af), were inhibited under ozone treatment, which also suppressed the degradation of cell wall components associated with fruit softening (protopectin, soluble pectin, cellulose, and hemicellulose). These changes may contribute to the maintenance of cell wall components, thereby delaying the fruit softening. In conclusion, these results suggested that ozone can improve the fruit quality of cantaloupe by suppressing postharvest fungal diseases and delaying fruit softening, which provides a theoretical basis for further research on cell wall metabolism during cantaloupe storage.