Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green tomatoes’ future foretold

07.03.2002


Fruit’s hidden colour reveals whether it will ripen.



Some green tomatoes have a rosy future; others do not. A sensor that picks up subtle differences in the light the fruits reflect could sort future salads from greens.

Many tomatoes are picked green and bathed in ripening gas ethylene. Fruit picked too early will never ripen. Discerning consumers avoid them and growers lose out.


A scanner that analyses the wavelengths green tomatoes bounce back can predict those that ultimately will ripen, Frederico Hahn of the Centre for Investigation of Food, Sinaloa, Mexico, has shown1. Some of the world’s annual 60 million tonnes of tomatoes could be saved this way, he hopes.

"Maybe you can find some clues that ripening will happen," agrees Ian Young who is working on similar detectors at the Delft University of Technology in the Netherlands. "We’re looking for ways to do things that the market hasn’t even thought of," says Young.

Like Hahn, fruit sorting company Colour Vision Systems, in Bacchus Marsh, Australia, uses infrared spectroscopy to measure the sugar content of melons and stone fruit. The technology could be adapted for tomatoes, concedes one of their scientists Gary Brown, though, at present, it may be too expensive.

Colour coding

Some fruit packers already use automatic colour sorters to grade the ripeness of their fruit. Conventional cameras measure red, green and blue wavelengths emitted, and classify the produce before boxing. The United States Department of Agriculture has six official colour classifications: green, breaker, turning, pink, light red and red.

But to these cameras, one green tomato looks like another. So size, shape and internal appearance are used to judge when a green crop is on the turn.

Hahn’s sensor instead measures all wavelengths over a large part of the visible and invisible spectrum. He analysed 300 green Gabriela tomatoes before storing them for 10 days.

Fruit that never ripen emit more intensely at some infrared wavelengths on day one, he found. The green pigment chlorophyll has a characteristic emission of infrared light that changes during ripening, as chlorophyll degrades and red and yellow pigments called carotenoids accumulate.

Hahn used these key wavelengths to develop a ripeness predictor. It foretold maturity with over 85% accuracy on 600 fruit, for which visual inspection proved useless.

References
  1. Hahn, F. Multi-spectral prediction of unripe tomatoes. Biosystems Engineering, 81, 147 - 155, (2002).

HELEN PEARSON | © Nature News Service

More articles from Agricultural and Forestry Science:

nachricht No soil left behind: How a cost-effective technology can enrich poor fields
10.10.2019 | International Center for Tropical Agriculture (CIAT)

nachricht Cheap as chips: identifying plant genes to ensure food security
09.10.2019 | University of Göttingen

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Fraunhofer LBF and BAM develop faster procedure for flame-retardant plastics

21.10.2019 | Materials Sciences

For EVs with higher range: Take greater advantage of the potential offered by lightweight construction materials

21.10.2019 | Materials Sciences

Benefit and risk: Meta-analysis draws a heterogeneous picture of drug-coated balloon angioplasty

21.10.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>