METHYL SALICYLATE: A TRENDY COMPOUND MARKER OF ZELEN, A UNIQUE SLOVENIAN VARIETY

Abstract

The wine market interest for autochthonous varieties, particularly from less known wine regions, has significantly raised in the past few years. In that context, Slovenia, a small country from central Europe with a long winemaking tradition, is getting more and more attention, particularly through its range of unique regional varieties. Among them, Zelen, meaning “green” in Slovene, can only be found in the Vipava valley region, located on the western side of the country, near the border with Italy. When they are young, Zelen wines display very singular aromas reminiscent of rosemary, sage and white fruit. Despite its uniqueness, Zelen wine aromatic typicality is poorly documented in the literature. The goal of this study was to highlight some potential aromatic markers specific to Zelen in comparison to other international and regional varieties grown in Slovenia. A first batch of 28 white wines from different Slovenian wine regions including 8 Zelen wines, were analysed for their contents in volatile thiols by GC/MS/MS, terpenoids, and untargeted screening by HS/SPME-GC/MS. Thereafter a second batch of 67 wines from Vipava valley including 25 Zelen wines, were analysed for their contents in methyl salicylate and volatile phenols by HS/SPME-GC/MS. The first batch of analyses showed that Zelen had lower content in volatile thiols and higher concentration in some monoterpenols such as linalool in comparison to other varieties. Nevertheless, two com- pounds identified with the untargeted analysis seemed to be particularly important in Zelen wines aro- matic profile: methyl salicylate and 4-vinylguaiacol. The second batch of analysis confirmed this trend with the average concentration of methyl salicylate at 14 µg/L and 3 µg/L in Zelen and other wines respectively. The highest concentration was measured at 38 µg/L in one Zelen wine, which corresponds to the sensory threshold measured in neutral white wines [1]. Methyl salicylate has recently gained some attention as it was found that this compound could contribute to the Italian Verdicchio and Lugana wines aromatic profile [1,2] and to some Bordeaux red wines made under specific conditions [3,4]. Zelen wines also displayed higher concentrations of 4-vinylguaiacol with 30% of Zelen wines having concentrations above the perception threshold reported for white wines [5]. Preliminary sensory investigations suggested that both compounds could potentially contribute to Zelen aromatic typicality.