You may soon be able to tell if a fruit is ripe or not, thanks to a new handheld device developed by MIT researchers, including one of Indian origin. The device can evaluate how ripe the fruit is by measuring the glow of chlorophyll in the fruit’s skin under ultraviolet light.
Such a gadget could make a big difference for apple distributors, who sometimes have to guess when deciding where to send their stock, researchers said. Testing ripeness could also help farmers decide the best time to harvest their crops. “There’s a tremendous amount of wastage,” said Anshuman Das, a postdoctoral researcher in Massachusetts Institute of Technology (MIT)’s Media Lab.
One solution could be to analyse apples using a spectrometer, which measures the brightness of light at specific wavelengths. However, current spectrometers tend to be big and expensive, tabletop-size devices, which makes them not practical for most apple sellers and farmers.
Using entirely off-the-shelf parts, Das and colleagues built a spectrometer that employs ultraviolet light to make the chlorophyll in the skin of an apple fluoresce. The riper an apple is, the dimmer the glow from the chlorophyll, the researchers said.
When the spectrometer picks up the light from the apple, it sends the data to an Android phone app via Bluetooth that compares it to a previous database of what an apple should be like at given stages of ripeness, ‘Live Science’ reported.
The user can then see how many days the apple has been ripening from a baseline amount. For example, the spectrometer can say an apple has been ripening for 10 days, and that means that a batch of 10-day-old apples should be shipped out before the three-day-old ones do, and ideally, they should be sent to stores nearby.