Spray-On Hydrogel Coating To Delay Ripening of Bananas Being Developed

Bananas are one of the oldest harvested fruits. They are from herbaceous plants of the genus Musa. Banana plants are native to tropical areas in the South and Southeast Asia. The banana plant, often mistaken for a tree, is the largest herbaceous flowering plant.

Bananas grow in clusters hanging from the top of the plant and come in different sizes and colors. When ripe, bananas turn yellow, purple, or red.

Bananas are an excellent source of vitamin B6, soluble fiber, and contain moderate amounts of vitamin C, manganese and potassium.

Export bananas are picked green. These are refrigerated in lower temperatures to halt the ripening process. When ready, they are put in special air-tight rooms filled with ethylene gas to induce ripening.

For tree ripened bananas, retailers immediately put them on sale since the shelf life for these fruits are limited to only 7–10 days.

Good news for banana lovers: Help may be on the way to slow that rapid over-ripening

A solution finally may be at hand for the number one consumer gripe about America's favorite fresh fruit ― bananas and their tendency to ripen, soften and rot into an unappetizing mush, seemingly in the blink of an eye.

Scientists speaking here today at the 244th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society, described efforts to develop a spray-on coating that consumers could use to delay the ripening of those 6.4 billion pounds of bananas that people in the U.S. eat every year.

The coating is a so-called "hydrogel," a superabsorbent material like those with many medical and commercial uses, made from chitosan, a substance derived from shrimp and crab shells. Xihong Li, Ph.D., who presented the report, noted that chitosan is attracting considerable attention in efforts to keep fruits and vegetables fresher longer due to its action in killing bacteria that cause produce to rot, low cost and other properties. Until now, however, it has not been used to slow the ripening of bananas.

"We found that by spraying green bananas with a chitosan aerogel, we can keep bananas fresh for up to 12 days," said Li, who is the study's leader. "Once bananas begin to mature, they quickly become yellow and soft, and then they rot. 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."

MIT News: New Sensor Developed To Detect Spoilage in Fresh Foods

Every year, U.S. supermarkets lose roughly 10 percent of their fruits and vegetables to spoilage, according to the Department of Agriculture. To help combat those losses, MIT chemistry professor Timothy Swager and his students have built a new sensor that could help grocers and food distributors better monitor their produce.

The new sensors, described in the journal Angewandte Chemie, can detect tiny amounts of ethylene, a gas that promotes ripening in plants. Swager envisions the inexpensive sensors attached to cardboard boxes of produce and scanned with a handheld device that would reveal the contents’ ripeness. That way, grocers would know when to put certain items on sale to move them before they get too ripe.

“If we can create equipment that will help grocery stores manage things more precisely, and maybe lower their losses by 30 percent, that would be huge,” says Swager, the John D. MacArthur Professor of Chemistry.

Detecting gases to monitor the food supply is a new area of interest for Swager, whose previous research has focused on sensors to detect explosives or chemical and biological warfare agents.

“Food is something that is really important to create sensors around, and we’re going after food in a broad sense,” Swager says. He is also pursuing monitors that could detect when food becomes moldy or develops bacterial growth, but as his first target, he chose ethylene, a plant hormone that controls ripening.