Spray-on coating helps keep bananas from spoiling


August 23, 2012

Scientists have developed a hydrogel that lengthens the shelf life of bananas (Photo: Shutterstock)

Scientists have developed a hydrogel that lengthens the shelf life of bananas (Photo: Shutterstock)

Just about everyone loves bananas, but there is one problem with the things – they have a way of becoming overripe before they can be eaten. Yesterday, however, a scientist from China’s Tianjin University of Science and Technology announced the development of a spray-on coating that is capable of keeping picked bananas fresh for almost two weeks.

Like other fruit and vegetables, bananas remain “alive” after being harvested, and respire (or breathe) through their skin. The faster that a fruit respires, the faster that it ripens. Unlike many other fruits, however, the respiration rate of bananas does not slow down after they’re picked. This causes them to ripen more quickly than most fruits, to the point that they often become brown and mushy before they’re consumed.

The coating, which is a type of hydrogel, works by slowing down respiration and killing a type of bacteria that causes the fruit to rot. Its key ingredient is chitosan, which is a compound found in crustacean shells – something that the seafood industry generates plenty of. Researchers have also looked into using chitosan for applications such as biocompatible transistors, self-healing paint, and virus filters.

When a team led by Dr. Xihong Li sprayed the hydrogel onto green bananas, they remained unspoiled for up to 12 days. How long bananas normally last is somewhat subjective, as different people like them at different stages of ripeness, although generally one week is about their maximum shelf life.

Li envisions a commercial version of the coating being used by consumers, supermarkets, or during transport. He presented his findings in Philadelphia, at the 244th National Meeting & Exposition of the American Chemical Society.

Source: ACS

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

Fruits and vegetable also "inhale" anything sprayed on them through their skins. I would not touch such sprayed bananas without knowing a great deal more about the hydrogel and its contents. China does not have a particularly great track record in food safety.


Banana hangers extend the shelf-life of ripening bananas, too. Small side effect is that banana hangers don't expose the fruit to chemicals about which consumers know little.

Peter Kingsbury
Post a Comment

Login with your Gizmag account:

Related Articles
Looking for something? Search our articles