ISHS Acta Horticulturae 275: International Symposium on the Culture of Subtropical and Tropical Fruits and Crops
EFFECT OF ETHYLENE TREATMENT ON THE RIPENING, POLYPHENOLOXIDASE ACTIVITY AND WATER-SOLUBLE TANNIN CONTENT OF TAIWAN NORTHERN BANANA AT DIFFERENT MATURITY STAGES AND THE STABILITY OF BANANA POLYPHENOLOXIDASE |
| Authors: | W.H. Chang, Y.J. Hwang |
| Abstract:
Bananas of maturity stages of 0.6, 0.7 and 0.8 were treated at 20°C with ethylene concentrations ranging from 0 to 100 ppm, and the effect of these treatments on respiration rate and ethylene formation was determined. Ethylene concentrations higher than 0.8 ppm increased the respiration rate but inactivated the system responsible for endogenous ethylene formation. The opposite result was observed at ethylene concentrations of 0.3 ppm and lower. Bananas harvested at maturity stage 0.8 ripened normally without application of exogenous ethylene, but those harvested at 0.6 and 0.7 maturity stages required exogenous ethylene for normal ripening, suggesting that the optimum stage of maturity is 0.8. The optimum concentration of exogenous ethylene was 0.3 to 0.8 ppm. The effect of ethylene treatment on polyphenoloxidase (PPO) activity and changes in water-soluble tannin content as well as the stability of PPO were also investigated. Ethylene treatment accelerated PPO activity and changes in water-soluble tannin content. During ripening tannin was translocated from the peel to the fruit pulp where it was metabolised by the PPO. PPO activity was optimal at pH 8 to 8.5, and the PPO was fairly heat resistant. | |
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