Do androids dream of electronic sheep? No one knows, but robots may soon be ‘tasting’ real food, with a new range of electronic tongues, developed by Belgian scientists to improve tomato grading.

The VCBT is presently testing three methods this year: infrared absorption, the enzymatic biosensor and the electronic tongue. Once the best option has been identified, it will be possible to substantially increase the number of taste tests on Flandria tomatoes starting in 2008.

Taste tests play a decisive part in determining which new tomato varieties qualify for inclusion in the Flandria segments. They are currently carried out by human taste panels from the Provincial Centre for Applied Research on Vegetables in Kruishoutem.

The number of varieties and, in particular, the number of samples per variety that the taste panels can test is necessarily limited. To enable much broader-based assessment, Flandria would like to supplement the Kruishoutem taste panels, starting in 2008, with an electronic technique that determines and interprets the taste components of a tomato quickly and objectively. In each case the tomato to be tested is first centrifuged to obtain a juice. Infrared absorption makes use of sophisticated measuring equipment that automatically spreads the drops of juice over a test plate. The drops are then irradiated with infrared light. The degree to which the juice absorbs infrared radiation indicates the concentration of the different taste components (especially sweet and sour; to a lesser extent, salt).

The enzymatic biosensor works with a robot that automatically adds an enzyme solution to a plate containing 96 microreservoirs filled with tomato juice. The juice changes colour and the changes provide an accurate indicator of the concentration of the various taste components.

The third method, known as the ‘electronic tongue’, works with 28 sensors that are linked to a computer. Each sensor provides information about a taste component.

“Another version of the electronic tongue has been on the market for a while, but our research showed that it wasn’t stable enough,” explains Bart Nicolaï , VCBT’s scientific coordinator. “That’s why we’re now working with a different electronic tongue that was developed at St Petersburg University in Russia. It’s not perfect yet, but it’s much more stable. Together with the university’s researchers, we’re working on refining the method.”

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