You mean bananas with brown skin, right, not brown flesh? Pineapple is different; it has much more moisture which will hasten spoiling. I don't cook with it enough to say for sure about the taste, but I would store it in the fridge until you're ready to use it. Maybe even cut it into rings and freeze those, to prevent it from deteriorating further.
Anyplace where people argue about food is a good place.
~ Anthony Bourdain, Parts Unknown, 2018