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 High conductive foils enabling large area lighting
29.06.2017 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

nachricht Fraunhofer Researchers Develop High-Pressure Sensors for Extreme Temperature
28.06.2017 | Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

High conductive foils enabling large area lighting

29.06.2017 | Power and Electrical Engineering

Designed proteins to treat muscular dystrophy

29.06.2017 | Life Sciences

Climate Fluctuations & Non-equilibrium Statistical Mechanics: An Interdisciplinary Dialog

29.06.2017 | Seminars Workshops

VideoLinks
B2B-VideoLinks
More VideoLinks >>>