Abstract:

To investigate the effect of salicylic acid (SA) on antioxidation capacity and preservation of banana fruit, fruits were divided into two groups with 90 banana fingers each, comprising triplicate of 30 bananas. One group treated with SA was immersed in 0.8 mmol/L SA solution for 4 hours, while the control group was immersed in distilled water for 4 hours. After immersion, the fruits were dried in air and then stored at the electric thermostat at 25 ℃ under 85% relative humidity for storage. Activities of antioxidant enzymes, H2O2 content in pericarp and pulp, starch and soluble sugar content, fruit firmness were measured after 0 d, 3 d, 6 d and 9 d respectively. The results indicated that activities of superoxide dismutase (SOD) and catalase (CAT) in the pericarp are higher than those in the pulp of fruit, while peroxidase (POD) activity is on the reserve. SA treatment can significantly increase the activities of SOD, CAT and POD, and reduce the contents of H2O2 and malondialdehyde (MDA) in fruits. Moreover, SA can decrease the degradation rate of starch to soluble sugar in pulp of fruit, enhance the firmness and decrease fruits decay index, and in turn SA improves preservation of fruits. It's suggested that SA could evidently enhance antioxidation capacity and preservation effect of harvested banana fruits by increasing the ability of eliminating reactive oxygen species in fruits.

Key words: banana, salicylic acid, reactive oxygen species, reactivities of antioxidation enzymes, starch