Abstract
Changes in chlorophylls (Chls) content, flavonoids level, and peroxidase and chlorophyllase activities were determined to clarify the pathway of Chl degradation in ethylene-treated satsuma mandarin (Citrus unshiu Marc.) fruits.
Chls content in the fruits decreased considerably even during ethylene treatment and then showed a sharp decline during storage at 20°C. On the other hand, Chls content in the fruits treated without ethylene decreased gradually after 1 day of storage. In the fruits treated with ethylene, Chl degradation activity, which shows the phenolic compound level involved in Chl degradation by a peroxidase-hydrogen peroxide system, increased markedly to a maximum on day 2, and then decreased to the original level. Chls were greatly degraded by the peroxidase-hydrogen peroxide system in the presence of naringenin and apigenin, which implies that flavonoids might relate to Chl degradation by the peroxidase system. The activities of peroxidase and chlorophyllase in ethylene-treated fruits increased significantly with the advance of degreening.
These results infer that Chls in ethylene-treated fruits might be degraded by the peroxidase pathway together with the chlorophyllase action.
