• The
threshold value is the concentration at which an aroma or taste can be detected (air, water and fat). • The
recognition threshold or
arousal threshold of
olfactory neurons is the concentration at which an odor can be identified (air, water and fat). • The
odour activity value is the concentration divided by the threshold. • The
flavor impact is the value the rate of change in perception with concentration. • The
flavor contribution of an
aroma component in a mixture to the total profile can be calculated from the total odor units and the number contributed by that aroma chemical.
Odor detection value Odor threshold value (OTV) (also
aroma threshold value (ATV),
Flavor threshold) is defined as the most minimal
concentration of a substance that can be detected by a
human nose. Some substances can be detected when their concentration is only few
milligrams per 1000
tonnes, which is less than a
drop in an
Olympic swimming pool. Odor threshold value can be expressed as a concentration in water or concentration in air. Two major types of flavor thresholds can be distinguished: the absolute and the difference threshold. The odor detection threshold and the odor recognition threshold are absolute thresholds; the first is the minimum concentration at which an odor can be detected without any requirements to identify or recognize the stimulus, while the second is the minimum concentration at which a stimulus can be identified or recognized. The odor threshold value of an odorant is influenced by the medium. Examples of substances with strong odors: •
Grapefruit mercaptan (OTV = 0.1
ppt) •
Sotolon (OTV = 1 ppt) •
Geosmin (OTV = 10 ppt) •
strawberry furanone (OTV = 40 ppt) ==Variables==