Abstract: The fresh-keeping effect and mechanisms of pre-harvest chlorine dioxide (ClO2) treatment on ‘Red Fuji’ apple were studied. Red Fuji apples were sprayed with 0, 20, 50 mg/L and 80 mg/L ClO2 before harvest. Physiological indicators were measured regularly during storage and decay index was counted in the end. Pre-harvest ClO2 treatment could considerably scavenge colonies on fruit surface, inhibit the decrease in fruit hardness and titratable acid content, reduce respiration rate, ethylene release and decay index and increase the activities of POD and PAL, but have no obvious inhibitory effect on fruit weight loss. The appropriate concentration of ClO2 was 50 mg/L, resulting in an obvious fresh-keeping effect and a considerable prolongation of the shelf life.

Key words: Red Fuji apple, chlorine dioxide (ClO2), cold storage, pre-harvest treatment, preservation