Postharvest cold storage-induced oxidative stress in Japanese plums (Prunus salicina Lindl. cv. Amber Jewel) in relation to harvest maturity

Abstract

Cold storage-induced oxidative stress in relation to harvest maturity and storage duration together with its implications on fruit quality and storage potential of Japanese plums (Prunus salicina Lindl.) were investigated. ‘Amber Jewel’ plums harvested at commercial maturity and one week after commercial maturity (delayed harvest) were stored at 0 °C for 7 weeks. Oxidative stress related parameters were determined at weekly intervals. Similar to lipid peroxidation, the incidence and severity of chilling injury (CI) was higher in fruit from the delayed harvest compared to commercial harvest. The activities of primary antioxidant enzymes and ascorbate-glutathione cycle enzymes were determined in context to the levels of antioxidant pools of ascorbate and glutathione and the development of CI symptoms. The predominance of the oxidized state of the tissue as reflected by lower ratios of ascorbate (AA) to dehydroascorbate (DHA) and reduced glutathione (GSH) to oxidized glutathione (GSSG) was linked to the severity of CI symptoms during the last 3-4 weeks of storage. The status of enzymatic and non-enzymatic antioxidative system during cold storage of Japanese plums appeared to be more important in providing protection against oxidative injury expressed as CI than at-harvest antioxidant status. Delayed harvested fruit experienced more oxidative stress during cold storage compared to the fruit harvested at commercial maturity. In conclusion harvesting ‘Amber Jewel’ plums at commercial maturity is of paramount importance to ensure long-term cold storage with minimal adverse effects on fruit quality for better consumer experiences.