Chilling injury (CI), which causes seed browning in pepper, may arise following long-term cold storage, and is a major cause of postharvest losses. To explore potential strategies of minimizing the associated postharvest losses, the present study investigated the optimal pepper harvest time that could reduce levels of seed browning, in addition to the relationship between fruit maturity and seed browning. Fruit harvested 15 days after flowering (DAF) were sensitive to cold storage at 4°C and exhibited 100% seed browning (CI index, 4.0); in contrast, the seed browning rate of fruit harvested 35 DAF was 10% (CI index, 0.4) within 7 d of cold storage. Seed antioxidant activity was higher in seeds harvested at early stages (15 DAF to 20 DAF) than in seeds harvested at later stages (40 DAF to 50 DAF) at the beginning of storage. Pericarps of fruit harvested at 50 DAF exhibited the highest antioxidant activity. Lipoxygenase, catalase, and peroxidase activity, and the expression levels of cell wall-related genes, pectin methylesterase-like protein, and endo-β-1,4-glucanase were higher in seeds of immature fruit harvested 15 DAF than in seeds of mature fruit harvested 35 DAF. The endosperm separated from the seed coat in fruit harvested 35 DAF and the seeds did not brown under low-temperature storage. The lack of seed browning observed in mature fruit under low-temperature storage could be attributed to physical protection provided by the seed coat rather than cold stress resistance conferred by antioxidants.

Oriental melons have a relatively short shelf life as they are harvested during the summer season and susceptible to cold-induced injuries. Typical chilling injury when stored at 4℃ is expressed as browning of the fruit suture. To prolong the shelf life and reduce browning of the fruit, the effects of modified atmosphere packaging (MAP), X-tend modified atmosphere (MA)/modified humidity (MH) bulk packaging (XF), and polyethylene (PE) packaging, on oriental melons were investigated during storage at 4℃ and 10℃ for 14 days and under retail display conditions at 20℃. The O2 concentrations in PE packages stored at 4℃ and 10℃ ranged from 17.4–18.5%, whereas those in XF packages were reduced to 16.3–16.6%. The CO2 content of XF package (4.2–4.6%) was higher than that of PE package (1.4–1.9%) stored at 4℃ or 10℃. Relative humidity (RH) saturated in the PE packages but not in the XF packages after seven days of storage. Furthermore, PE packages performed better at maintaining melon weight and firmness than XF packages during storage at 10℃ for 14 days and under retail display conditions at 20℃. PE and XF packages effectively reduced the browning index of the peel and white linear sutures of oriental melons compared with the unpackaged control during cold storage at 4℃, and this observation was maintained at the retail display condition at 20℃. The enhanced CO2 levels, reduced O2 levels, and optimal RH values that were provided by the MAP, prevented the browning symptoms and improved the marketability and shelf life of oriental melons.