# Chemical Characterization and Volatile Profile of Trebbiano di Lugana Wine: A Case Study
## 3 Results
### Sensory Evaluation  
Among the descriptors selected by the panelists, significant differences were found for yellow intensity, olfactory (O-) intensity, O-fruity, O-grapefruit/boxwood/passion fruit, O-floral, O-oxidized/marsala, O-honey, acidity, aftertaste (AF-) fruity, AF-peach and AF-marsala/honey/oxidized (Table 4). Concerning the yellow intensity descriptor, significant differences were found for the older samples, namely 2005, 2009 and 2011. The highest score (8/9) was assigned to the wine of 2005, while there were no differences in terms of intensity of the yellow color between the wines produced in 2011 and 2009 (score: 6/9). This result is supported by both the color analysis (Table 1) and the absorbance values at 420 nm (Table 2). In fact, depending on the storage time, increased values of absorbance at 420 nm, chroma and a decreased value of hue were reported [23; 54]. The yellow intensity descriptor did not result in a significant difference between the wines from 2017, 2016, 2015 and 2013 for which the panel assigned the same score (5/9), as supported by CIELab analysis and \(\Delta\)E values (Table 1). Considering the olfactory attributes, the lowest O-intensity was found for the wines produced in 2009, 2013 and 2015. In order to better clarify the relation between sensory attributes and volatile compounds, PCA was carried out, taking into account the effect of the storage time (Figure 2). The results showed that the first two components were significant in explaining 95% of the total variance, of which 88% was explained by P1 and 7% by P2. The wine samples were distributed on P1 as a function of the time of storage, and the youngest ones were mainly characterized by the presence of esters. As storage time increased, the wines stored for 13 and seven years (2005 and 2011, respectively) were characterized by intensity of yellow color, honey, marsala and oxidized descriptors associated with furfural (Figure 2). P2 was related to the vintage whose role will be further investigated in future studies. The decreased perception of fruity note for increasing storage time (Figure 2) can be associated with the decay of ester content (Table 3). The esters described with fruity notes and associated with the perception of the fruity descriptor were ethyl acetate, ethyl butanoate, isoamyl acetate, ethyl hexanoate, hexyl acetate, ethyl lactate and ethyl dodecanoate; \(\beta\)-damascenone was also included (Figure 2). Similarly, the perception of floral notes decreased for longer storage as the contents of higher alcohols (1-hexanol, 1-octanol, 2-ethyl-1-hexanol, 2-phenylethanol), esters (ethyl butanoate, ethyl isovalerate, ethyl decanoate, acetic acid, phenylethyl acetate, ethyl dodecanoate), norisoprenoids (\(\beta\)-damascenone) were significantly lower (Table 3). Interestingly, the wines produced in 2009 and in 2015 showed the same score for floral descriptors (4/9) (Figure 2). This finding was unexpected and is difficult to explain; the higher content of glutathione detected in the 2009 wine could limit the loss of aroma compounds, including esters and monoterenes [51; 52; 53]; particularly, favorable vintage or limited oxidative phenomena could preserve the fruity notes and, consequently, the floral and fruity notes. Moreover, increased scores were found for oxidized/marsala descriptors associated with the wine storage, with the exception of the wine from 2009 (Table 4). Likewise, the honey descriptor, a possible sensory marker of oxidative reactions, was perceived more in the 2005 and 2011 wines than the other samples (Figure 2). For the olfactory perception of boxwood/grapefruit/passion fruit descriptors, three groups were identified as wines produced in 2005, 2009 and 2011, wines of 2013 and 2015 and wines of 2016 and 2017 (Figure 2).