To keep a bunch of bananas fresh for longer, wrap the stems in some plastic wrap. Re-cover the bananas with the wrap after removing one. This method prevents ethylene gas, produced naturally in the ripening process, from reaching other parts of the fruit and prematurely ripening it.
Should you refrigerate bananas?
Answer: Yes — once they have reached the ripeness you like, you should refrigerate your bananas. The cooler temperature of the refrigerator will slow down the spoilage process and keep the bananas tasty for about five more days. ... If you refrigerate under-ripe bananas, their flavor and texture won't develop properly.