Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electronic tongue has good taste

09.01.2002


Coffee producers could use the electronic tongue for quality control.
© PhotoDisc


Hand-held tasting device displays highly discriminating palate.

A new hand-held electronic tongue promises to give accurate and reliable taste measurements for companies currently relying on human tasters for their quality control of wine, tea, coffee, mineral water and other foods.

Human tasters are still irreplaceable for subtile products such as fine wines and whiskies. But their sense of taste saturates after a while, losing its discriminating edge. The device made by Antonio Riul of EMBRAPA Instrumentação Agropecuária in São Carlos, Brazil, and colleagues rivals human taste buds and never tires1.



The electronic tongue can sense low levels of impurities in water. It can discriminate between Cabernet Sauvignons of the same year from two different wineries, and between those from the same winery but different years. It can also spot molecules such as sugar and salt at concentrations too low for human detection.

Questionable taste

Humans have long been thought to detect four basic taste types: sweet, salty, sour and bitter. Very recently, a fifth candidate basic taste was identified: umami, the taste of monosodium glutamate, characteristic of protein-rich foods. Taste buds are believed to contain receptor molecules that trigger nerve signals when they encounter flavour-imparting molecules.

The details of this system are still not understood. Each taste sensation may correspond to a fingerprint signal induced by the differential activation of the various taste receptors. The electronic tongue works on this principle.

It contains four different chemical sensors. The sensors comprise very thin films of three polymers and a small molecule containing ruthenium ions. These materials are deposited onto gold electrodes hooked up to an electrical circuit.

In a solution of flavoursome substances such as sugar, salt quinine (bitter) and hydrochloric acid (sour), the thin sensing films absorb the dissolved substances. This alters the electrical behaviour (the capacitance) of the electrodes in a measurable way.

Each sensor responds differently to different tastes. A composite sensor that incorporates all four therefore produces an electronic fingerprint of the taste. The researchers combine these responses into a single data point on a graph. The position on the graph reflects the type of taste: sweet lies towards the top left, for example, sour towards the top right.

Different beverages have a characteristic location on the graph. Coffee is low down around the middle, for instance. Some tastes that might be expected to differ only slightly, such as distilled and mineral water, lie far apart on the graph and so can be clearly distinguished.

The electronic fingerprint allows the team to predict what a particular solution will taste like, says Martin Taylor of the University of Wales at Bangor, who collaborated with the Brazilian team. "It might fit in the salty or sweet domain, for example," he says. Taylor anticipates that the device will probably be able to discriminate the umami taste too, giving it a refined palate for sushi.

References

  1. Riul, A. et al. Artificial taste sensor: efficient combination of sensors made from Langmuir-Blodgett films of conducting polymers and a ruthenium complex and self-assembled films of an azobenzene-containing polymer. Langmuir, 18, 239 - 245, (2002).


PHILIP BALL | © Nature News Service

More articles from Power and Electrical Engineering:

nachricht Fraunhofer ISE Supports Market Development of Solar Thermal Power Plants in the MENA Region
21.02.2018 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht New tech for commercial Lithium-ion batteries finds they can be charged 5 times fast
20.02.2018 | University of Warwick

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Researchers invent tiny, light-powered wires to modulate brain's electrical signals

21.02.2018 | Life Sciences

The “Holy Grail” of peptide chemistry: Making peptide active agents available orally

21.02.2018 | Life Sciences

Atomic structure of ultrasound material not what anyone expected

21.02.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>