Year 12 | 28 January 2020 | email@example.com
The presence of organoleptic defects will be assessed by routine chemical analyses. This is the future, but probably the professional tasters will not disappear since the assessing of harmony, equilibrium and pleasantness cannot be left to cold sensors
The tasting panels are criticized for many reasons:
- Long times for a result
- High training costs
- Low reproducibility among different panels, in particular if coming from different geographical areas.
Besides these problems, the organoleptic exam is still the pivotal test for assessing the commercial category for an olive oil. But those limitations, in particular the long time required for an evaluation, put the producers on the spot since the time from production to market needs to be fast to meet the market needs.
Given that the tasters will be still irreplaceable for long time, because of the human capability to perceive the complexity, the equilibrium and the harmony of oil, some of the duties of the panels could be soon given to automatic systems. The latter are reproducible, objective and fast.
The Aromolio project of the Arsia Toscana Association compared three different analysis systems to assess the capability of automatic systems to carry out specific tasks, such as the spotting of flawed samples. The preliminary results are encouraging.
The Dynamic Test Space (GC-MS) method agrees with the taster panel, except for the fruity defect and the fruity attribute. The same results were obtained for the solid phase micro-extraction method (HS-SPME-GC-MS).
Both the methods were able to spot the presence of molecules specific for many defects. Some of those compounds show very high correlation coefficients, resulting in perfect markers for the defects usually perceives with senses. The butyl acetate is strongly correlated with the heat defect, the ethylene propionate with the sludge, the guaicol ethyl with the mould and the 2-4 heptadienal is associated with the rancid.
Some of these results confirm literature but some others are new and very interesting, such as the one concerning the sludge defect. Moreover, it is noteworthy that, by using these methods, in some cases it was also possible to spot some defects missed by the panel. As a matter of fact, in many cases, once the tasters spot a defect out, they tend to ignore other defects. This is obviously not the case for automatic methods.
Nevertheless, such positive results are not enough to consider those methods more accurate than humans. The same quantity of different molecules have different effects on the olfactory profile of an oil; then, besides spotting the presence of a molecule, it is also necessary to determine the minimal concentration that produces a defect. This is the next step of the research.
As for the electronic nose, it gave good results in spotting the flawed samples, except for the avvinato and the sludge defect. On the contrary of the above methods, the electronic nose also showed a high degree of accordance with the panel as for the positive characteristics of bitter, spicy and fruity.
All the researchers involved in this project, presenting their results at the Medoliva, underlined that these methods need to be trained and calibrated with the official tasting panels in order to be fully effective and objective. The human senses are still the most sophisticated and complex tool for assessing the commercial classification of an olive oil.
by Alberto Grimelli
05 july 2010, Technical Area > Olive & Oil