Ozone fumigation promotes antioxidant activities to retard chlorophyll degradation and cell death in ‘Jinda’ chili during storage

Chlorophyll degradation plays a crucial role in mediating the senescence and devaluing of 'Jinda' chili fruit after harvest. The objective of this study was to investigate the effect of ozone fumigation on the chili fruit quality in relation to ROS-mediated chlorophyll degradation and cell death-related processes. Green chili fumigated with ozone (50 mg L−1) for 30 min was examined for antioxidant systems, chlorophyll degradation and cell death-related enzymes during 12 d of storage. The dissipation of pericarp degreening and reddening of pericarp color were observed on day 3 of storage, which were associated with the significantly elevated levels of superoxide and hydrogen peroxide accumulations, as well as increased chlorophyll catabolic enzymes (chlorophyll peroxidase, chlorophyllase and pheophytinase activities). Moreover, both caspase-like enzymes and in situ DNA degradation, features of programmed cell death (PCD), became more obviously visible at the early period of deterioration. Fruit fumigated with ozone, enhanced the activity of antioxidant enzymes (ascorbate peroxidase, catalase and superoxide dismutase) and suppressed both chlorophyll degradation and the PCD process, which were compatible with lowering senescence in chili. Our findings showed that ozone fumigation increases antioxidant activity, which in turn helps to delay chlorophyll breakdown and cell death, hence slowing senescence in 'Jinda' chili.