Delaying fruit softening of ‘France’ prune (Prunus domestica L.) using near-freezing temperature storage

To delay ‘France’ prune fruit softening during storage, the effects of near-freezing temperature storage (NFTS; −1.5 ∼ −1 °C) on cell wall polysaccharides, cell-wall-modifying enzyme activities, cell-wall-modifying genes, and tissue ultrastructure of ‘France’ prune fruit were determined. The results showed that NFTS kept a higher fruit firmness (70.9%) compared to the control group (22.6%) at the end of storage. Besides, after 12-day storage, NFTS suppressed the activities of cell-wall-modifying enzymes, the expression of key cell-wall-modifying genes, the dissolution of chelate-soluble pectin (53.1%), Na2CO3-soluble pectin (114.6%), cellulose (81.3%), and hemicellulose (95.2%), and ethylene production (19.7%), and maintained lower water-soluble pectin (38.2%) and lignin contents (16.0%), compared to the control group. Ultrastructural observation showed that NFTS could delay the disassembly of pectin components and protect cell wall structure. In conclusion, NFTS can effectively inhibit fruit softening and maintain fruit quality.