(In)sensitivity to another aroma in tea and wine...

Another aroma compound to which people may be insensitive is beta-ionone. It occurs in both tea, particularly oolong, and wine, especially Pinot noir. And there seems to be a conditional insensitivity to beta-damascenone, a significant aromatic compound in black tea and several different types of wine. By contrast, people do not seem to differ significantly in their thresholds for alpha-ionone, a minor component of both tea and wine.*

All of these compounds are also components of orange juice, so Plotto and colleagues used orange juice “pumpout” (which is deodorized orange juice concentrate) and water as carriers for their threshold determinations. Participants sniffed the samples to determine their orthonasal thresholds, then sipped the samples to determine their flavor thresholds.

Participants differed by orders of magnitude in their thresholds for beta-ionone dissolved in both pumpout and water. The same held true for beta-damascenone in pumpout, but not in water. There was no real difference among participants in their thresholds for alpha-ionone.

X-axis: serial dilutions of beta-ionone in water and pumpout.

Y-axis: frequency of thresholds at a given dilution.

Note that there appears to be two separate groups, one relatively sensitive and one relatively insensitive, as manifested by two separate peaks of frequency.

Interestingly, even at each participant’s threshold, beta-ionone gave different odor and flavor impressions. It was pleasant for participants with low thresholds—they characterized it as “floral, grape, sweet, soapy, perfumey” in water, and “floral, berries, soapy, perfumey” in pumpout. By contrast, participants with high thresholds included “musty, cleaner, plastic” for beta-ionone in pumpout, and “herbal, plastic, chemical” for the chemical in water—in other words many less sensitive participants found the odor and flavor of beta-ionone unpleasant at threshold. 

This study leaves a bunch of questions in my mind: First and foremost, what do these threshold differences mean for the enjoyment of wine and tea? Second, could a person be trained to develop a lower threshold for beta-ionone, and if so, could this training improve their experience of wine and tea? Third, would these kinds of differences in threshold exist for other compounds characteristic of wine and tea? Fourth, how does the ability to perceive beta-damascenone play out in wine and tea, if the thresholds in water are not so different? etc….

So much more research to be done!

* A. Plotto, K.W. Barnes, K.L. Goodner. Specific Anosmia Observed for β-Ionone, but not for α-Ionone: Significance for Flavor Research. Journal of Food Science, Vol. 71, Nr. 5, 2006, pages S401-S406.