EFFECTS OF NITRIC OXIDE ON POSTHARVEST QUALITY AND SOLUBLE SUGAR CONTENT IN PAPAYA FRUIT DURING RIPENING

The present study was performed to investigate the effect of nitric oxide (NO) fumigation on fruit ripening of harvested "Sui you 2" Carica papayas in relation to postharvest quality and soluble sugar content. Fruits were fumigated for 3 h with 60 mu L/L NO and stored at 20C and 75% relative humidity for 20 days. NO treatment effectively suppressed ethylene formation and respiratory rate (CO2 levels), reduced weight loss, maintained firmness and delayed changes in peel color and soluble solid contents during 20 days of storage. The level of vitamin C initially increased and then declined slightly during storage at a slower rate in the NO-treated fruits than in controls. Exposure to 60 mu L/L NO resulted in significant decreases in fructose and sucrose content. Glucose content in NO-treated fruits was higher than that in controls. Our results indicate that NO gas can be used to prolong fruit storage life and delay changes in soluble sugar content in papaya fruit.