The Quality Of Meat

A sensor developed by a team of analytical chemists of the Voronezh Technological Academy allows you to determine the quality of meat, to learn whether it is fresh, and how long it has been kept. Researchers headed by Professor Yakov Korenman and Tatiana Kuchmenko, Doctor of Science (Chemistry), have produced a sensor which helps to quickly and accurately analyse the scent of meat; to identify the adipose and muscular tissue oxidation products through the piesoelectric microweighing method.

The fact that meat stored in freezers deteriorates over time is well-known. This happens among other things due to interaction of meat tissues with atmospheric oxygen – the tissues get oxidized. But this is difficult to determine by smell, and most importantly, a qualitative indicator not a quantitative one is required. A device is needed, which (in contrast to the nose of an average statistical person) is impossible to deceive by masking odours, for example – by spices. This particular effective, keen and selective device has been developed by the chemists.

The authors suggest that the smell of meat, or more precisely – the gas phase above the meat surface – should be analyzed simultaneously with the help of several so-called electrodes. These are quartz plates, on the surface of which thin films of various substances are applied to efficiently catch the “smell components” – 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. As for the coatings, the researchers have tried all kinds of compounds, including even beeswax.

The point is that having “snatched” some molecules from the air – of course not any molecules but the ones that owe their appearance in the air to the meat product – the coatings slightly put on weight. The difference is negligibly small, however, it changes quartz plate vibration parameters under the influence of imressed voltage. The change in vibration parameters is the analytical response, which may be recorded and measured. To increase such analysis selectivity, the researchers used several electrodes, each of them showing heightened sensibility to this or that smell component, i.e. it captures the smell component more selectively and reliably.

Then it was necessary to teach the obtained sensor – to give it the references for “smelling”, i.e. the meat with different shelf lives. The composition of meat changes in the course of storage, and this, in turn, is inevitably reflected on the gas phase composition above the meat – i.e. on its smell. According to the researchers, the analysis result should be 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 object under consideration.

Thus the weighed smell of meat acquires visual outlines – something like a flower with different petals. 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. But the analysis of adipose tissue diagrams has showed that the piesoelectric weighing method can catch even the very unnoticeable changes in the fat quality. It’s a pity that there is along way from the laboratory to the store where such devices could be purchased, although it does not depend on the researchers. They have done their job – they have developed the laboratory sample of the sensor. The sensor is used successfully.