TALLAHASSEE, Fla. — Tired of throwing away those leftover bananas you didn’t eat in time before they turned brown and mushy? Get ready for a potential game-changer in the produce industry. Bananas that don’t turn brown could be on the horizon, according to new research. The color-changing phenomenon has been slowed by scientists, offering hope for reducing tons of food waste.
Bananas lose their shine and quickly go soggy because of too much oxygen. The world’s most popular fruit is regularly ignored in fruit salads – as it makes other ingredients dark too. Now, scientists from Florida State University are out to change things.
Researchers shed fresh light on the phenomenon by simulating spot patterns on banana skins. Many fruits turn brown when cut, damaged, or stored for longer periods of time – a process caused by air and enzymatic reactions. The process leads to an estimated 50 million tons of food waste as stores and consumers throw out banana fruits due to their unappetizing appearance.
“For 2019, the total production of bananas was estimated to be 117 million tons making it a leading crop in the world,” says lead author Oliver Steinbock, a professor in the university’s Department of Chemistry and Biochemistry, in a statement. “When bananas ripen, they form numerous dark spots that are familiar to most people and are often used as a ripeness indicator. However, the process of how these spots are formed, grow, and their resulting pattern remained poorly understood, until now.”
A combination of time-lapse videos and computer models has now revealed for the first time how they evolve. Oxygen concentrations and browning degree of the banana peel showed the spots appear during a two-day window and rapidly expand, but then mysteriously stall. The root cause suggests mitigation strategies could compete with genetic engineering and storing the fruit in cooled containers or under a modified atmosphere.
Formation of the spots was slowed by decreasing oxygen levels in their tiny formation sites.
“Fruit browning continues to be a major challenge for the food industry,” says Steinbock. “Our study offers a model for banana spotting which is capable of capturing their evolution in a physically meaningful context and which can be applied to procedures to mitigate food waste.”
The study in Physical Biology could end the shunning of bananas in mixes, such as supermarket fruit salads. They go brown because of an enzyme called PPO (polyphenol oxidase). Bananas make other fruit ripen because they release ethene. The gas causes ripening, or softening of fruit, by the breakdown of cell walls, conversion of starches to sugars and the disappearance of acids.
“It’s really a very tricky business because bananas are very complicated systems,” Steinbock says. “If you cool them, you slow down the browning, but you mess with the taste. You can spray something onto the surface to reduce the gas exchange, but that will indirectly change the taste. It’s not an easy problem.”
South West News Service writer Mark Waghorn contributed to this report.