Why does keeping a ripe banana or apple with unripe fruit help the unripe ones ripen faster?
Ripening fruit releases ethylene, a gaseous plant hormone that triggers ripening — softening, sweetening and colour change.
Ripening fruit releases ethylene, a gaseous plant hormone that triggers ripening — softening, sweetening and colour change. A ripe banana gives off plenty of ethylene, so enclosing unripe fruit with it (say in a paper bag) surrounds them in the gas and speeds their ripening. Fruit sellers use ethylene for exactly this, and the reverse — good ventilation — slows ripening in storage.
Key point
Ethylene gas from ripe fruit triggers ripening in nearby unripe fruit.
Common mistake
thinking ripening only depends on time, not on a chemical signal.
Memory tip
ethylene is the ripening gas — trap it with the fruit to speed things up.
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