Don't miss the piglix.com special BONUS offer during our Beta-test period. The next 100 new Registered Users (from a unique IP address), to post at least five (5) piglix, will receive 1,000 extra sign-up points (eventually exchangeable for crypto-currency)!

* * * * *    Free piglix.com Launch Promotions    * * * * *

  • Free Ads! if you are a small business with annual revenues of less than $1M - piglix.com will place your ads free of charge for up to one year! ... read more

  • $2,000 in free prizes! piglix.com is giving away ten (10) Meccano Erector sets, retail at $200 each, that build a motorized Ferris Wheel (or one of 22 other models) ... see details

Odor detection threshold


The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. The threshold of a chemical compound is determined in part by its shape, polarity, partial charges, and molecular mass. The olfactory mechanisms responsible for a compound's different detection threshold is not well understood. As such, odor thresholds cannot be accurately predicted. Rather, they must be measured through extensive tests using human subjects in laboratory settings.

Optical isomers can have different detection thresholds because their conformations may cause them to be less perceivable for the human nose. It is only in recent years that such compounds were separated on gas chromatographs.

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:

Threshold in a food is dependent upon:

The concentration of an odor above a food is dependent on its solubility in that food and its vapor pressure and concentration in that food.



  • The threshold of the aroma in air.
  • Concentration in the food
  • Solubility in oil and water
  • Partition coefficient between the air and the food
  • The pH of the food, some aroma compounds are affected by the pH - weak organic acids are protonated at low pH making them less soluble and hence more volatile.
  • Number & functionality of odorant receptors in the observer's nose
...
Wikipedia

1,000 EXTRA POINTS!

Don't forget! that as one of our early users, you are eligible to receive the 1,000 point bonus as soon as you have created five (5) acceptable piglix.

...