Researchers in Japan have achieved a breakthrough that will make farms more efficient and curb food wastage throughout the value chains.
The team that is based at Tokyo’s Shibaura Institute of Technology in Tokyo will be working with Laser-induced Plasma shockwaves which create vibrations on a fruits surface.
These vibrations are what the scientists ate using to tell the ripeness of fruit.
This technology can potentially help to make agriculture more efficient right from the farm.
With a more accurate measure of ripeness, growers can now pack fruit that is just ripe enough to the picked. Neither too rope nor too unripe.
Farmers will be able to time their harvests perfectly.
Retailers will not purchase overripe or unripe fruit.
When consumers buy unripe fruit or underripe fruit, this equally results in wastage.
Farmers, retailers, and consumers use different methods to check ripeness of fruit.
Most of the time, this involves putting pressure on the fruit either using hands or a hammer or some type of instrument.
These methods register varying degrees of success, depending on what fruit they are applied on.
Mechanical techniques are most popular, even though some professionals use optical as well as biomedical techniques.
Mechanical methods assess the firmness of the fruit and this measure can be used to deduce the ripeness of the fruit
It doesn’t suit softer fruit that easily suffers mechanical damage.
The new method does not require any form of mechanical pressure or contact.
It uses LIP (Laser Induced Plasma) instead of force to assess the ripeness of fruit. LIP is so much better because it does not damage the fruit.
LIP works better with hard fruits for whom mechanical pressure may not work. In a plasma state, atoms are already stripped of electrons and they now have an electric charge.
When a high energy laser beam is focused onto a small pocket of air, it produces a similar effect of inducing an electrical charge.
The plasma bubble expands and emits shockwaves faster than the speed of sound.
Researchers have experimented with shockwaves before, generating them near the skin of a fruit and observing the resultant vibration which they dubbed ‘football mode vibration’ because of the way spherical bodies deform to create a shape that resembles a football.
The researchers checked that the vibrations had a frequency that reflected how firm the skin of the fruit was.
The scientists used Rayleigh waves which appear on the fruit’s surface because fruits don’t show this kind of vibration.
The technique was first demonstrated using Kent mangoes to prove that the speed of the Rayleigh waves can be used to tell how ripe the fruit is, even without touching the fruit or applying any pressure to it.
Mangoes have large seeds that change the way surface waves are propagated and this makes the measurements harder to read. The researchers found that they could measure rayleigh waves along the mango’s equator line for consistent results instead of using the prime meridian line.
Besides large seeds, deformities like cavities and decay have the capacity to alter the measurements of rayleigh waves.
With time, the scientists came up with a set of best practices to guide them in measuring the ripeness of soft fruit using rayleigh waves. According to Professor Naoko Hosoya, the system has enabled contact free ways of measuring the firmness of a fruit: “Our system is suitable for non-contact and non-destructive firmness assessment in mangoes and potentially other soft fruits that do not exhibit the usual [football mode] vibrations.”
