Visitors of Meat Technology Laboratory of Kaunas University of Technology (KTU) are advised not to use intensive perfume for this may overbalance the electronic nose that records the bouquet of odours in the environment being investigated. A team of scientists, in order to refine the software of electronic nose designed by IT solutions company Art21 conducts laboratory tests with poultry samples.
According to the hierarchy of senses suggested by Aristotle, the sense of smell is below sight or hearing, and in the modern world, smell is more of a decoration than a source of information. For example, many people talk about what essential oils have calming effect and which of them has a stimulating effect (in some case, however, not always, these statements have a scientific substantiation), however scientific studies on how human scent can signal diseases are relatively new and poorly developed.
However, if we talk about food, sense of smell is the main sense: 90 percent of what we call taste is actually smell. Nose “decides” whether we like certain meal or not, and, which is even more important, whether it is suitable for eating.
Electronic nose does not have bad mood
No matter how proud we are of our sense of smell, we cannot smell microorganisms or radioactive contamination that makes food unsafe to eat. “Smell is a set of volatile compounds emitted by any object or product. Scientific articles on meat alone identify several hundreds of such compounds”, – said Dr. Rimantė Vinauskienė who supervises the group of chemists conducting experiments with electronic nose. Different food products have different smell, and for example, chicken tight will have a smell different from chicken breast.
Human nose differs not only in its shape or length but also how good it can smell. Some of us are more sensitive to smells while others are less sensitive. Moreover, how strong we feel one or another smell depends on our mood, how was our morning, and in what was the mood of our boss.
Contrary to this, electronic nose is not subject to human factor. Its sense of smell is not dependent on sex, hobbies, or personal traits of the person that manages it. “Of course, for electronic nose to become smarter than a human nose, a human being must provide it with that “brain”, – smiled docent of the Department of Food Technology. Electronic nose has sensors to recognize certain organic compounds, including carboxylic acids, hydrocarbons, and aldehydes. In a laboratory, this nose is learning to smell when the product is still suitable for consumption and when it is not. “We purposefully investigate the changes in the compounds that signals deterioration”, – claims Vinauskienė R. who has defended doctoral thesis on volatile compounds indicating deterioration.
We should more rely on our senses
Despite electronic nose is many times more sensitive than human nose and is capable to inform about the condition of a certain food product more accurately, we will barely ever refuse information provided by natural senses. “Human being perceives any environment through sight, smell and sense of touching”, – explained R. Vinauskienė while presenting experiments conducted by the students in the KTU Meat technology laboratory investigating the effect of food additives, processing, and technologies on meat flavour and quality characteristics.
For example, smoked products have a different smell, and the colour shows the product has been exposed to smoke. Moreover, the scientists immediately denied the popular myth that smoked meat products are prepared by soaking them into or by spreading them with a liquid saturated with smoke extracts. “Of course, technologically it is possible to obtain smoke extract. There exists technological equipment in the world that could help to embed the flavour of smoke into the products. Nevertheless, as far as I know, no one in Lithuania has such equipment. After all, it would totally not worth the cost”, – the scientist remarked to sceptics. R. Vinauskienė advised not to be distracted by light spots on smoked products or sausages – such lighter spots occur at the points of bending, or at the places where products are in contact with one another.
There are still unrevealed possibilities left
Though electronic nose currently smells only chicken, it has enough work. “Smell of poultry depends on the breed of fowls as well as feed and growing conditions. Spoilage periods are also different”, – claimed Vinauskienė R. We have all seen how different is meat of corn-fed chicken from the meat of a chicken which grew in a farm or of a commercially grown broiler. Chemical composition of meat, i.e. the amounts of protein, fat, and other major components are very similar, however the sensory characteristics, including smell, are totally different. What characteristics of smell make food especially attractive? Is it possible to distinguish the “miraculous” chemical compound of delicious food? Can nose reliably warn about the spoilage processes starting in the product?
“The diamond has been mined and now we are working on polishing it”, – smiled Vinauskienė R. when talking about the studies still waiting for the electronic nose until all its possibilities are revealed.
The potential of electronic nose can be seen in the following video: http://www.youtube.com