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| Poster #364 1,1,6-Trimethyl-1,2-dihydroxnapthalene (TDN) is a common odor defect of Riesling wine (petrol) that screams “Riesling” at subthreshold levels. |
| Leanne Y LI, Hanfei Liu, Yao Jiang, Milan Poland, Leto Solla, Terry Acree Cornell University, Ithaca, NY, United States |
The idiosyncratic odor character of white wines, caused by their viticulture, enology, and aging, is a consequence of the ratios of a small subset of Key odorants. Riesling shares these key odorants with many white wines while maintaining its unique identity. 1,1,6-Trimethyl-1,2-dihydroxnapthalene (TDN), a unique odor defect in Riesling has a ‘petrol’ note when present above its threshold but it is found near its threshold in most Rieslings. In rat neurobiology, a “silent note” is a nonlinear response that creates mixture identity (Xu and Firestein 2021). We have investigated the role of TDN concentration in the recognition of Riesling character as a “silent note”. We presented Riesling-familiar subjects with 75ms duration puffs of 10mL Chardonnay headspace containing different ratios of TDN and measured their response to the binary forced-choice: “Riesling” or “not Riesling”. The response probability was fit to logistic models of response probability vs molar concentration of TDN in the Chardonnay. Separately, Riesling-familiar subjects were stimulated with the same Chardonnay-TDN samples but were asked “petrol” or “not-petrol”. These results were fit to a logistic model, with the predicted 0.5 probability of recognizing “petrol” defined as the threshold for TDN in Chardonnay. The subjects had similar but unique thresholds for TDN perceived as “petrol” in Chardonnay wine, but all subjects responded positively to recognition of “Riesling” odor at concentrations of TDN below the threshold for TDN in Chardonnay. At super-threshold levels, TDN in Chardonnay is recognized as “petrol”, a defect of Riesling. At sub-threshold levels in Chardonnay, TDN creates a “silent note” that screams Riesling. |