Occurrence, biogenesis and sensory impact of methyl salicylate in Lugana wines

Lugana wines are produced in the winemaking regions of Veneto and Lombardia, employing Turbiana grapes grown in the proximity of the Garda Lake. Methyl salicylate (MeSA) has been reported as a potentially impactful compound in Lugana wines. The aim of this study was to evaluate the occurrence of MeSA in commercial Lugana wines, elucidate its formation during winemaking and aging, and assess its potential contribution to Lugana aroma. MeSA was quantified in a total of 93 samples including Lugana, Verdicchio (another Italian white wine produced in central Italy using Turbiana grapes locally referred to as Verdicchio), as well as other Italian white and red wines such as Corvina, Corvinone, Garganega, Sangiovese, Pinot nero, Pinot grigio. The results showed that Lugana showed an average concentration of MeSA of 50.6 µg/L, Verdicchio of 33.4 µg/L, while the rest of the wines showed concentration below 5 µg/L. These results indicate that MeSA can be considered a varietal marker of Lugana wines, as well as more in general of wines obtained from the Turbiana/Verdicchio varietal cluster. Concentration of free MeSA in Lugana grape must is however low, and experimental fermentations showed that MeSA was largely formed by yeast activity during alcoholic fermentation, which hydrolyzes the glycosidic precursors of MeSA present in the must to release the aglycone. Additional MeSA can be formed in wine during aging by acid hydrolysis of the glycosidic precursors. Finally, the olfactory threshold of MeSA in a commercial Lugana was estimated by BET method at 38 µg/L, suggesting that MeSA could play a role in Lugana aroma.