Abstract:

Our goal in this study was to evaluate the efficacy of diphenylamine (DPA) treatment on reducing oleocellosis
in Valencia orange fruits (Citrus sinensis L. Osbeck) and its mechanism. The results showed that 7 mmol/L DPA treatment
was significantly effective to control oleocellosis in Valencia orange fruits, which could enhance the activities of antioxidant
enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and
glutathione reductase (GR) and the contents of antioxidant compounds. In addition, there was a decline in polyphenoloxidase
(PPO) activity in DPA-treated fruits during the later period of storage. These results indicated DPA treatment could alleviate the
symptoms of oleocellosis in Valencia orange fruits by regulating malondialdehyde (MDA) level and antioxidant enzyme activity.

Key words: Valencia orange fruit, oleocellosis, diphenylamine, antioxidant