Ask the Expert: Why Do Bananas Make Everything Taste Like Bananas?

Bananas photo via istock.com/bhofack2

It’s a tale as old as time.

You toss a banana in your lunch bag. You leave it in there all morning. Then, when break time finally comes, you discover the inevitable: Everything, from your sandwich to your pretzels, tastes and smells vaguely of banana.

What gives? We asked Vinay Mannam, an assistant professor of food science and chemistry at Framingham State University, for answers.

Ask the Expert: Why Do Bananas Make Everything Taste Like Bananas?

Answer: Chemistry is to blame here.

The details:

“Bananas are a fruit,” Mannam says. (Roger that.) “In nature, the purpose of the fruit is to decompose so that seeds can get into the ground and regrow the plant.”

So when, aided by enzymes, bananas begin to brown—which is harmless at first, but acts as a sign of ripening and decomposition—they’re just fulfilling their natural duty. But, Mannam says, “browning reactions generally produce very distinct flavors and overpowering flavors,” hence your suddenly fruity ham sandwich.

Bananas owe their unique scent and taste to an organic compound called isoamyl acetate. It’s found in several fruits—and, oddly, a small amount is produced from a bee sting—but it’s especially prominent in bananas. “The smell with banana is very particular,” Mannam says. “It’s very strong.”

The fruit’s distinctive characteristics also explain why it’s all you can taste in your morning smoothie. To combat that, Mannam suggests adding sweet fruits that’ll mask the taste, such as berries and apples.

As for the old lunch bag conundrum? Unfortunately, Mannam says “it’s very hard” to stop the mid-day flavor mayhem.

You can try choosing the least-ripe fruit possible, in the hopes that browning has not yet begun. But when it comes right down to it, he says, “the simplest way is to just bag it separately.”