## 3 Results and Discussion
The clustered heatmap computed on both VOCs and sensory quantitative data measured on a subset of eight samples (Figure 2) confirms the discriminability of Aglianico and Primitivo wines that were correctly clustered according to the grape variety. This confirms the intra-varietal similarity and the inter-varietal diversity of the two wine types. The clustering between VOCs and sensory data shows correlations not easy to interpret; however, some remarks seem to be of interest. Indeed, even if significant differences between the two wine types were not found in terms of terpenols levels (Table 1), the heatmap shows that beta-citronellol, alpha-terpineol and beta-linalool are positively correlated with Aglianico wines while negatively correlated with Primitivo ones, suggesting that they might serve as molecular markers of varietal origin to distinguish between these two single-varietal wines. In a recent study conducted on a larger sample-set and by applying a headspace VOCs isolation technique, [PERSON] et al. [19] determined the terpenoids composition in some Italian red wines including Aglianico and Primitivo. In this study, beta-citronellol, alpha-terpineol and beta-linalool were detected among other terpenoids, but no evidence of their potential discriminating power between the two wine types was found. From a sensory point of view, Aglianico wines do not strongly correlate with floral notes, a descriptor associable to terpenols. This could be due to the higher level of  
Figure 2: Heat map visualization of the wines (four Aglianico: AGL; four Primitivo: PRI) according to volatile composition and olfactory characteristics classified by a hierarchical cluster. higher alcohols in Aglianico wines (Table 1), as such as 2+3-methyl-1-butanol and isobutyl alcohol [41], which are aroma suppressors of some powerful aroma compounds [42; 43]. In Figure 2, these two alcohols were clustered together with phenylethyl alcohol and the \"alcoholic\" descriptor, in line with the concept of \"alcoholic-solvent aroma vector\" recently developed ([39], and references therein). As hypothesized above for Aglianico wines, the \"alcoholic\" sensory variable shows a positive correlation with three out of four Aglianico samples. On the other hand, 75% of Primitivo wines included in the HCA show positive correlations with the floral descriptors and, even if negatively correlated with the three detected terpenols, good correlations with other compounds associated with the floral aroma vector are highlighted, namely beta-phenethyl acetate and beta-ionone [38; 39]. In recent years, many works have investigated the effects of the interactions between volatiles. Many authors observed the capacity of some VOCs to enhance or mask the perception of other odorants present in the matrix, and the related olfactory attributes [23; 24; 25; 26; 44; 45; 46; 47]. It is, nowadays, clear that the olfactory profile of a given wine cannot be explained exclusively by the presence of volatile compounds related to a specific note, but also by the synergistic effect of different volatiles and/or by the presence of other VOCs negatively affecting its perception [23; 48]. Therefore, the correlations found between volatile compounds and sensory descriptors and their relationships with the specific wine samples investigated in the present work need to be further investigated.