A SPRAY-on coating made from a substance found in crab shells can prevent bananas ripening too fast and keep them fresh for up to 12 days, scientists claim. Bananas become mushy and sickly sweet notoriously quickly because unlike most fruits, the rate at which they “breathe” through their skin does not slow down after they ripen. Instead of remaining ripe for several days this means the fruit continues to produce sugars from its pulp, allowing the bacteria on its skin to multiply which causes the banana to rot. Now scientists have slowed down the rotting process using an absorbent coating made from chitosan, a substance taken from the shells of shrimp and crabs. The researchers, from Tianjin University of Science and Technology in China, presented their findings at a meeting of the American Chemical Society. Lead researcher Dr Xihong Li said: “We found that by spraying green bananas with a chitosan aerogel, we can keep bananas fresh for up to 12 days. “We have developed a way to keep bananas green for a longer time and inhibit the rapid ripening that occurs. Such a coating could be used at home by consumers, in supermarkets or during shipment of bananas.” Before releasing the gel to market, however, he added that one of its current ingredients would have to replaced with an alternative to make it suitable for mass production.  –Telegraph