Various sources on the internet claim to have the answer to making bananas last longer. Whether it be to separate each banana or to cover their stems in plastic wrap, I have tested these claims and, unfortunately, found them to be false…at least in my case. Perhaps a difference in air quality or temperature would change the results, however, I am not convinced.
What I have found is that the above suggestions have the same result: bananas will ripen in the same amount of time.
Bananas are considered to be climacteric fruits, meaning they have a high respiration rate and continue to ripen once picked (source). These fruits emit ethylene, a natural plant hormone, which accelerates the ripening process (source). The existence of ethylene then initiates the production of pectinase, an enzyme which causes bananas to soften as they ripen (source).
According to my experiment, separating bananas and even wrapping their stems in plastic wrap don’t slow the ripening process. While I do not have the magic answer for making bananas last longer, I recommend peeling and wrapping each banana in plastic wrap and storing in the freezer until ready to use, should you not plan on using your bananas within a couple of days. Keep in mind, however, that once frozen then thawed, bananas cannot be consumed like a banana fresh out of the peel due to having a mushy consistency. These types of bananas, however, are excellent in smoothies!