Ask an expert: Why do bananas ripen fruit?
A reader question delves into the secret life of fruit hormones.
QUESTION: Why do bananas ripen other fruit?
Andrew Burns, Surry Hills, NSW
Dr Mala Gamage, CSIRO food scientist, says:
As they ripen, bananas, apples, kiwi fruit, tomatoes, figs, pears and some other fruits release a gaseous plant hormone known as ethylene. These 'climacteric' fruit, as they are called, will respond to ethylene in their environment and begin the ripening process. As they do so, they ripen other fruit (and perish flowers) around them.
Bananas are medium-level producers of ethylene compared with kiwi fruit, for example, which produce more. But because bananas are large, and often you'll have a bunch of them in your fruit bowl, they can appear to be the cause of other fruits ripening.
Ethylene gas is also used commercially to ripen bananas.
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