Pick a peck of sesquiterpenes

Sesquiterpenes. Isn't that a nice word? Doesn't it flow off the tongue? I think it does.

Sesquiterpenes are compounds that often also flow onto the tongue quite well. Limonene, one of the major components of citrus rind, is one such compound. Delicious!

A new sesquiterpene was just discovered by some enterprising food scientists that is among the most potent odorants ever discovered! Rotundone, so named perhaps for its rotund appearance, is detectable at levels of 4 nanograms per liter.


Picture an Olympic swimming pool full of pristine spring water - two and a half million liters of it. You would only need ten milligrams - the merest pinch - of rotundone to render the pool pungent. For comparison, capsaicin, the active ingredient in hot peppers, would only be detectable if we threw 2.5 grams of it into that swimming pool. That's 250,000 times the amount of rotundone. Not to mention the inherent hazards of handling that much capsaicin. Yikes.

The potency of rotundone is not the most interesting part of this story, however. The researchers found rotundone in their investigation of Shiraz grapes and wines, as they often have a pronounced peppery flavor.

Grapes, as you might be aware, do not typically taste like pepper.

Rotundone was the answer. After realizing how much the pure compound smelled like pepper, they decided to see if it was in, well, pepper, and it was! Until this discovery, the "peppery" aroma compound in pepper itself was completely unknown! That's the most important compound in one of the most important spices, hidden for this long.

Also, approximately 20% of the panel they used to test the limit at which the compounds could be detected couldn't taste anything - even at 4 micrograms per liter, 10,000 times greater than the detection limit. That means 20% of people could be missing out on the best part of pepper, and think that a good Shiraz is just like any other red wine.

Pity.