The perception of taste sensations.
The taste sensor is located in the oral cavity. The stimuli are not perceived with the same intensity in all areas of the mouth. The most sensitive part of the mouth is the tongue, although sensitive parts are the epiglottis, the palate and the sides and back of the neck.
The perception of taste οn the tongue
- All the senses
- Sweet, salty, acidic
- Salty acidic
- Αcidic only
- Sensitive to all tastes
- Sweet, acidic
- Bitter, sweet, acidic
Therefore, for a correct perception of flavors, the taster takes a small amount of the sample and keeps it in their mouth only for two seconds. Then they wait for 15 to 60 seconds and retry.
The first and second test is the most sensitive and a good tester should educate themselves so that in these two first tests they will make all the brain comparisons and make the estimation needed for his work.
The perception of the trigeminal nerve senses
The pungent stimulus/em>
The sense of the trigeminal nerve is closely connected with the pungent stimulus. Generally speaking, the perception of spicy is caused by irritants, which activate the trigeminal nerve in the mouth or nose. Testers often have difficulty separating the responses of trigeminal nerve from the responses of gustatory or olfactory system. For most compounds, the response of the trigeminal nerve requires concentration of the irritant much higher than that required for the gustatory or olfactory system response.
The perception of smell sensations
The sense of smell lies in the back of the oral cavity, where the olfactory alveoli are found on the epithelium, which, if opened, covers an area of about one square inch. These cells are connected to the olfactory center with olfactory nerves. The anatomy of the nose is such that only a small fraction of the inhaled air reaches the olfactory epithelium via the nasal cavity or through the back of the mouth when ingested. The maximum contact of the olfactory system with the test sample is achieved with moderate inhalation for 1-2 seconds. When the two seconds end, the receptors are adapted to the new stimulus and the tester should let 5-10 seconds pass before retry. In less time, these receptors have not had time to shake off the stimulus and thus cannot produce a proper sense of the new stimulus. This is because the odor filled the area where the stimulus should be reached and thus the ability of the tester is reduced to detect a specific odor or differences between similar odors.
Positive organoleptic properties
- Fruity Combination of taste-smell senses (flavor), characteristic of the oils derived from healthy, fresh olives collected at optimum ripeness stage. The fruity is perceived either directly through the nose or the back of this and depends on the variety of olives. This property is the most important in sensory evaluation of the new method, because if not understood, the tested oil will not be classified as excellent or virgin.
- Bitter Characteristic taste of oil from green olives or olives which begin to change color. It can be pleasant or not depending on the volume. However, in no case should it be considered as a flaw. Therefore, if the bitterness is perceived with greater intensity than half of the scale , it should be stated in the certificate of analysis so that those interested have knowledge and make some actions (e.g. mixing) if the consumer requests less bitter.
- Spicy (Pungent) Intense tingling sensation characteristic of oils produced at the beginning of the olive season mainly from olives that are still unripe. It is caused by the action of phenolic substances on the ends of the trigeminal nerve, it spreads throughout the oral cavity and eliminates a few seconds after the test. The savory intensity decreases during the olive ripening. We must not confuse this sense of gripping with that of rancid, in which the sense is very annoying and kept for much longer.
Negative organoleptic properties
- Atrochado (fusty)
Characteristic odor-taste (flavor) of oil that has been received from olives kept in piles, which are in an advanced stage of anaerobic fermentation.
- Moldy – damp (musty)
Characteristic odor-taste (flavor) of olive received from olives which have developed a large number of fungi and yeast after keeping fruit in humid conditions for several days.
- Dregs (muddy sediment)
Characteristic odor-taste (flavor) of oil that has been in contact with the sediment in the storage tanks. For this reason, we recommend decanting the olive oil after a reasonable period of time in another storage container taking measures to ensure that contact with air is the least possible.
- Winey- vinegar
Characteristic odor-taste (flavor) of oils which remind of wine or vinegar. This flavor is mainly due to a fermentation process in the olive fruit, which leads to the formation of acetic acid, ethyl acetate and ethanol.
Flavor which reminds of metal. It is characteristic of oil that has been in prolonged contact with metal surfaces during the crushing of the olives, mixing, pressing or storage.
Characteristic odor-taste (flavor) of oil that has undergone an oxidation process due to prolonged contact with ambient air. This flavor cannot be corrected.
Other adverse organoleptic properties
- Heated or burnt. Characteristic flavor of oil caused by excessive or prolonged heating during its production, particularly during thermo-mixing of the paste, if performed in unsuitable conditions.
- Hay – wood. Characteristic flavor of certain oils that have been produced from dried olives.
- Severe (Rough). Thick and pasty sensation produced in the mouth by some oils.
- Greasy. Typical odor-flavor of oil, which reminds of lubricant or mineral oil.
- Vegetable water. Flavor derived from olive oil after prolonged contact with vegetable water.
- Brine. Flavor of oil from olives which have been preserved in saline solutions.
- Esparto. Characteristic odor – taste of oil from olives crushed into new esparto mats. The taste may vary according to whether the bags are made of green or dried esparto.
- Earthy. Odor – taste of oil from olives which have been collected with earth or mud and not washed.
- Worm (Grubby). Odor – taste of oil from olives severely infected by larvae of the fruit fly.
- Cucumber. Odor – taste produced when the oil is packaged in hermetically sealed containers for a long time, especially in tins. This flavor is attributed to the formation of 2-6 nonadienal.