Device to gauge ripeness of tomatoes

Scientists have developed a new portable device that can measure the optimum ripeness of tomatoes without destroying the fruit. Researchers, including those from Polytechnic University of Valencia in Spain, applied the Raman spectrometer to culinary research.

The portable Raman spectrometer is a non-invasive instrument widely used in a whole range of sectors to observe the pigments present in a painting or a sculpture without having to extract any samples, thus preserving the integrity of the work in question.

"It is about transferring this technology, which had a specific use, to the kitchen. Our idea was to come up with a tool that could help producers find out when their tomatoes have reached their optimum ripeness point," said Josu Trebolazabala, from the University of the Basque Country in Spain. "This is achieved by using this technique and, what is more, without destroying the fruit," said Trebolazabala.

Researchers compared the results provided by the Raman spectrometer with those provided by a similar laboratory instrument. Even though the quality of the Raman spectra of the lab instrument was higher, the quality of the information provided by the portable instrument could be regarded as sufficient for the aim in mind, researchers said.

"The aim is to enable producers to go to the vegetable plot with this equipment, place the Raman probe on the tomato, and find out whether it is at its optimum picking point or whether it needs to be left longer so that it can ripen properly," Trebolazabala said.

The monitoring of the composition of the tomato fruit during its ripening phases has made it possible to observe the changes that take place in the composition of the tomato during its passage from an unripe state towards a ripe state, researchers said.

This innovative technique can be extrapolated to any other food that changes colour during its ripening phase. "Tests have been carried out on peppers and pumpkins, for example, and it is also possible to obtain the data on their composition," Trebolazabala said.