Despite growing environmental awareness, food waste figures are still staggering.some estimates Annual food spoilage in the European Union is about 173 kg per person., which amounts to 88 million tons annually. Similarly, in America, 12% of his fruits and vegetables are wasted in stores and supermarkets. Finding new ways to prevent food waste is an ethical and environmental imperative. One of the signs of ripening vegetables is the release of a plant hormone known as ethylene. This could be key to monitoring the food life cycle.innovative technology project Developed at MIT, very low concentrations of 15 ppm can detect this type of effluent. To accomplish this, they used a carbon nanotube grid containing palladium as a catalyst.
In their experiments, the researchers placed the new generation of sensors on glass slides. He then measured the release of ethylene from two of his flowers, a carnation and a purple lisianthus, over a five-day period. After detecting an ethylene spike on the first day of the experiment, they witnessed him bloom within a day or two. Purple eustoma flowers showed a slower increase in ethylene throughout the four days. As expected, this slowed flowering, with some not blooming at all throughout the experiment.
From copper to palladium
So far, no ethylene sensor has been developed, according to the researchers. The same team created a similar sensor in his 2012 based on a grid of thousands of carbon nanotubes and copper atoms. In this prototype, an ethylene atom was bonded to a copper atom, slowing it down. Deceleration levels therefore indicate the presence of ethylene. However, this model was inaccurate and copper tended to oxidize over time and become less efficient.
Now in a new generation of nanotubes, the research team chose palladium as the catalyst. This metal adds oxygen to ethylene in a process known as Wacker oxidation. Oxidation then temporarily transfers electrons to the palladium, which then passes to the carbon nanotube. This process increases the overall conductivity, allowing ethylene levels to be established when current is measured. One advantage of this new sensor is that it can detect ethylene in seconds. Once the ethylene is gone, the grid quickly returns to average conductivity.
Researchers believe the patent-pending sensor has interesting applications in the food industry, especially vegetables, fruits and flowers. This is because lowering the ethylene level slows down the ripening process. Additionally, as ethylene is the most widely produced organic compound in the world, this sensor can also be used to monitor production in various industries.
sauce: MIT
