|Development of an electronic nose based on piezoelectric quartz crystals to evaluate the aroma of cheese|
Maria Teresa S. R. Gomes
Execution dates - 2008-01-02 - 2011-01-01 (36 Months)
Funding Entity - FCT
Funding for CESAM - 51900 €
Total Funding - 51900 €
Proponent Institution - Universidade de Aveiro
The intensity and characteristics of the aroma of a cheese are very important both to consumer and producer. Different cheese varieties present characteristic smelling patterns, which are related with the properties and the processing of the used milk, the manufacturing methodology, the rennet used, ripening stage and storing conditions. Besides flavour, the aroma of cheese is part of its identity. Many of the cheese protected with origin denomination are now produced in industrial units that follow, as close as possible, the artisan processes and methodologies. However, very small deviations in the procedure, sometimes very difficult to identify, or considered irrelevant, can lead to the lost or intensification of compounds in the smell and to adulteration of the aroma that both for consumers and specialists characterize a certain cheese variety. The aroma of cheese can only be characterized by trained sensory panels, or, in a different way, by expensive analytical methodologies, such as gas chromatography.- mass spectrometry after quimiometric treatment of the results. Recently, electronic noses started to de developed. These are instruments that use an array of sensors that can be based in a few different type of transducers. The most electronic noses use metallic oxide semiconductors or acoustic wave sensors. These electronic noses intend to mimic the human nose by incorporating several sensors with different sensitivities to different compounds, or families of compounds. After calibration, the use of electronic noses would allow to obtain results that independent from human condition, such as fatigue, health, ingested food, or use of cosmetics. The use of these electronic noses for cheese is still very rare and some authors pointed the complexity of the matrix as a possible explanation. Therefore, it seems important that the electronic nose would be conceived for the type of compounds that exist in the aroma of cheese and that are most important for smell characteristics. The aim of this project is the assembling of an electronic nose based on acoustic wave sensors, specially designed for the evaluation of the aroma of cheese. After the development of the electronic nose, we intend to test and use it to distinguish cheese produced from raw and pasteurized milk, produced from flowers of Cynara cardunculus or animal rennet and stored in different conditions of light and temperature, but mainly in different ventilation conditions. Ventilation is suspected to may be the cause of differences detected in the aroma of artisan or manufactured cheeses, although there are no studies to confirm it.