US: New fruit ripeness sensor developed
The sensors can detect even the smallest amounts of ethylene, the gas that promotes ripening. The idea is to attach the sensors to boxes of produce so that they can detect ripeness and report back on it via handhold scanners. This would give retailers a strong indication of when to put things on sale and, crucially, when to take them off.
"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.
Plants secrete varying amounts of ethylene throughout their maturation process. For example, bananas will stay green until they release enough ethylene to start the ripening process. Once ripening begins, more ethylene is produced, and the ripening accelerates. If that perfect yellow banana is not eaten at peak ripeness, ethylene will turn it brown and mushy.
Fruit distributors try to slow this process by keeping ethylene levels very low in their warehouses. Such warehouses employ monitors that use gas chromatography or mass spectroscopy, which can separate gases and analyze their composition. Those systems cost around $1,200 each.
Swager says the cost of this is prohibitive and can only be utilized by large scale operations.
The researchers tested the new sensors on a wide array of fruit varieties including banana, avocado, apple, pear and orange. The results proved accurate.
John Saffell, the technical director at Alphasense, a company that develops sensors, describes the MIT team's approach as rigorous and focused. "This sensor, if designed and implemented correctly, could significantly reduce the level of fruit spoilage during shipping," he says.
Source: www.nanotech-now.com
