Why do bananas ripen "out of synch"?


In the past, I've encountered bananas which seem to be "out of synch", that is, the peel color is more ripe than the pulp tastes, e,g, a color 5 peel, but the pulp still hard and starchy, and vice versa, so that the peel is greener than the pulp would indicate.Do you have an explanation for why peel color does not always correlate well with pulp ripeness? (A.)


Temperature, carbon dioxide concentration, and prior exposure to 1-methylcyclopropene (SmartFresh) are three possible reasons for the lack of coordination between peel color changes and ripening (softening, starch to sugar conversion) of the pulp of bananas. At fruit temperatures above 30C (86F), the peel remains green while the pulp will ripen. These bananas are sometimes called “green ripe” and this can be a common situation in the tropics when bananas are ripened at ambient temperatures. Exposure of bananas during ripening at optimal temperatures (15–18 ºC = 60-65 ºF) to carbon dioxide levels above 5% (as a result of the high respiration rate at color 2 and 3 and lack of introduction of fresh air or scrubbing of excess carbon dioxide) will slow down peel color changes to a greater extent than delaying pulp ripening because the carbon dioxide antagonizes ethylene action. Similar results may be seen with bananas that were treated with the ethylene action inhibitor, 1-MCP (SmartFresh), at color stages 2 or 3 to extend the yellow-life of bananas. -