###### Abstract  
To determine the impact of oral physiology on the volatility of typical wine aroma compounds, mixtures of a synthetic wine with oral components (centrifuged human saliva (HS), artificial saliva with mucin (AS), and buccal epithelial cells (BC)) were prepared. Each wine type was independently spiked with four relevant wine odorants (guaiacol, \(\beta\)-phenyl ethanol, ethyl hexanoate, and \(\beta\)-ionone). Additionally, the impact of four types of phenolic compounds (gallic acid, catechin, grape seed extract, and a red wine extract) on aroma volatility in the HS, AS, and BC wines was also assessed. Static headspace was measured at equilibrium by solid phase microextraction-GC/MS analysis. Results showed a significant impact of oral components on the volatility of the four tested odorants. Independently of the type of aroma compound, aroma volatility was in general, higher in wines with BC. Moreover, while guaiacol and ethyl hexanoate volatility was significantly lower in wines with HS compared to wines with AS, \(\beta\)-ionone showed the opposite behavior, which might be related to metabolism and retention of mucin, respectively. Phenolic compounds also showed a different effect on aroma volatility depending on the type of compound and wine. Gallic acid had little effect on polar compounds but it enhanced the volatility of the most hydrophobic ones (ethyl hexanoate and \(\beta\)-ionone). In general, flavonoid type polyphenols significantly reduced the volatility of both polar (guaiacol and \(\beta\)-phenyl ethanol) and hydrophobic compounds (\(\beta\)-ionone in HS and BC wines), but through different mechanisms (e.g., \(\pi\)-\(\pi\) interactions and hydrophobic binding for polar and apolar odorants respectively). On the contrary, flavonoids enhanced the volatility of ethyl hexanoate, which might be due to the inhibition exerted on some salivary enzymes (e.g., carboxyl esterase) involved in the metabolism of this odorant molecule. wine; aroma volatility; aroma-matrix interactions; polyphenols; oral physiology; saliva; buccal cells +
Footnote †: journal: Medical  
by using more complex synthetic wines [8; 9] or reconstituted wines [10; 11]. All of them have provided valuable information on the outstanding role of some wine matrix components on aroma volatility highlighting the necessity to consider aroma-wine matrix interactions, and not only the wine aroma profile when trying to explain wine aroma perception [12]. However, and differently to what happens when a wine is smelt and its odor is perceived (orthonasal pathway), during eating or drinking, aroma compounds are released in the mouth and/or in the throat, and they travel pushed by the expiration flows to the olfactory receptors. Once in the mouth, wine components (volatile and non-volatile) can also interact with oral fluids (saliva) and structures (oral mucosa), which might also affect aroma volatility [13]. Recent in-vivo studies have shown differences in individual patterns of in-mouth aroma release which might be associated to differences in oral physiology [14]. Salivary flow and composition have also been related to differences on in-mouth [15] and in-nose [16] wine aroma release. Unfortunately, the molecular mechanisms behind these interactions remain poorly understood. The scarce studies trying to elucidate the nature of these interactions have been focused on the impact of saliva on wine aroma release by using different methodological approaches (static vs. dynamic headspace), wine matrix compositions (synthetic vs. real wines), tested odorants (mixtures of aroma compounds vs. original wine volatile profile), and salivary composition/treatment (e.g., saliva centrifuged/not centrifuged) [17; 18; 19].