Ethylene biosynthesis enzyme activities in the pulp and peel of partially ripe 1-MCP-treated Bananas

The study of effects of 1-Methylcyclopropene (1-MCP) on ripening of bananas is still an important issue for commercial application of 1-MCP on bananas. Mature green bananas were treated with ethylene only (100 µL L-1 for two consecutive days) and ethylene the same treatment followed by 1-MCP (300 nL L-1) for 24 h to evaluate the ethylene and 1-MCP effects on ethylene biosynthesis enzyme activities. Ethylene production of whole banana fruit, ACC synthase (ACS) and ACC oxidase (ACO) activities in the pulp and peel of samples were measured. The result showed that ethylene production rate by the control fruit was significantly greater than the ethylene production rate by the 1-MCP-treated fruit at days 4, 8 and 10. However, changes in ethylene production were similar in both control and 1-MCP-treated bananas. The banana peel and pulp show different patterns of ethylene production during ripening. At the onset of ripening pulp tissues showed higher levels of ACS, and lower levels of ACO activity than peel. Assays of ACO and ACS activities in ethylene-treated fruit showed that the peel had higher levels of ACO activity than the pulp. The ACO and ethylene production were inhibited by 1-MCP treatment whereas ACS increased following 1-MCP application.  Evaluation of ACS and ACO activities during different seasons.  Pulp and the peel of bananas respond differently to ethylene and 1-MCP treatment with a greater impact on peel than the pulp. The findings of this study allow 1-MCP to be used in a more commercially reliable manner.