We've all been there. You pack a banana in your bag for lunch or you stash a bunch of the yellow fruit in a cupboard and suddenly everything around them smells and tastes vaguely of bananas. It doesn't really happen with apple or oranges or any other fruit ... just bananas.
In the article, Mannam mentions that all fruit is meant to eventually decompose and release their seeds into the earth. "Browning" is one of the first signs of decomposition (but you already knew that, right?). "Browning reactions generally produce very distinct flavors and overpowering flavors," Mannam said.
But when it comes to that very present smell, a natural chemical compound called isoamyl acetate is largely responsible for the banana's potent taste and smell. According to this message board isoamyl acetate is especially soluble (which essentially means it gets everywhere). That banana smell can even penetrate plastic bags before sticking to any foods in the vicinity. The smell becomes more potent as the fruit ripens.
Several websites suggest that aluminum foil slows down the ripening/decomposition process and it's apparently solid enough to contain any isoamyl acetate from leaking into the rest of your lunch.
Business Insider also suggests using foil (or plastic wrap) to help slow down the ripening process. Bananas release ethylene gas, which helps them ripen. But that gas also causes any surrounding fruit to ripen as well, meaning your bunch of bananas (and surrounding fruit) will decompose much faster. Much of that gas is released in the stems, which can be slowed down by separating the bunch, and wrapping each banana stem in plastic or foil.
Hopefully these tips help so you can avoid eating a banana-flavored bag of chips and slightly banana flavored sandwich for lunch.