Sensor sniffs gases on meat to determine freshness

By Ahmed ElAmin

- Last updated on GMT

Russian scientists say they have developed a sensor that "smells" a
meat's gases to determine if it is fresh and how long it has been
kept in storage.

The sensor could help meat plants improve food safety through an accurate tester that can quickly be used to identify bad ingredients. Meat stored in freezers deteriorates over time in part due to the interaction of meat tissues with atmospheric oxygen - the tissues get oxidized.

However the extent of the process is difficult to determine by smell. What is needed is a device that is impossible to deceive by masking odours, for example with spices, lead researchers Yakov Korenman and Tatiana Kuchmenko said in announcing their invention.

Their sensor takes a reading of the gas above the meat's surface with several electrodes. The electrodes identify the gases produced by proadipose and muscular tissue oxidation through a piesoelectric microweighing method.

The electrodes are quartz plates, on the surface of which thin films of various substances are applied to catch the meat's "smell components". These are molecules evaporating from the surface of meat.

"As these molecules are rather diverse, there are several electrodes involved, each of them being covered with its own coating,"​ Korenman and Kuchmenko jointly stated.

Some of the coatings, include all kinds of compounds such as beeswax. Having sampled some molecules from the air surrounding the meat the coatings get heavier.

The tiny difference changes the vibration of the quartz plate under the influence of imressed voltage. The change in vibration is then recorded and measured.

The result is then represented in the form of the so-called lobed pattern, the size and shape of each lobe corresponding to each electrode's response to the gases found on the meat's surface.

"Thus the weighed smell of meat acquires visual outlines - something like a flower with different petals,"​ the scientists stated. " Absolutely fresh meat has one shape of a flower-pattern, stale meat - has another shape, and the meat stored for a day or two - has a different shape. The diagram of the fresh-killed meat cannot be mixed up with the diagram of cooled meat, particularly if the meat is fat."

This fact is rather important. The authors paid attention to noticeable differences by "visual imprints" in the muscular tissue scent are rather typical for long-term storage of lean meat, i.e. non-fat meat. That means that the fat gets out of order quicker, which is in principle obvious.

Their analysis of adipose tissue diagrams shows that the piesoelectric weighing method can catch even the very unnoticeable changes in the fat quality, they claim.

The sensor was developed by a team of analytical chemists of the Voronezh Technological Academy. They hope a commercial company will now be able to take their research and develop a product for the market.

Related topics: R&D

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