# Volatile Profiles of Sparkling Wines Produced by the Traditional Method from a Semi-Arid Region
## Results
### Volatile Composition
In relation to the esters ethyl butanoate and ethyl hexanoate, no difference was found between the four sparkling wines analyzed. Carboxylic acids are produced during alcohol fermentation and may have different origins. The hexanoic, octanoic, and decanoic acids can also be formed during the catabolism of the long chain fatty acids [6]. Depending on the concentration, these acids are related to a decrease in the sensory quality of wines [9; 14]. [PERSON] [39] showed that in concentrations of 4 to 10 mg L\({}^{-1}\) the C6 to C10 acids contribute to an agreeable wine aroma, while in concentrations above 20 mg L\({}^{-1}\) they have a negative impact on the organoleptic quality of wines. The sparkling wines produced by traditional method in the SFV presented higher normalized chromatographic areas for octonoic, hexanoic and n-decanoic acids (the last on was higher in CB+SY-R sparkling wines, as shown in Table 3). The high chromatographic areas of these acids may be related to two alcoholic fermentations that sparkling wines elaborated by traditional methods have undergone. [PERSON] et al. [8] observed an increase of the chromatographic area for almost all the acids identified in the volatile profile of base wines and their resulting sparklings. Sulphur compounds are originated from fermentative process contributing to the aromatic complexity of the wines, when present in low concentrations. However, in high concentrations, they may be responsible for unpleasant aromas [40]. As reported in Table 3, the 3-(methylthio)-1-propanol was identified in low normalized chromatographic areas in the sparkling wines produced in the SFV (ranging from 0.027 to 0.031). Aldehydes are formed from decarboxylation of unsaturated fatty acids and they can also be considered as products of lipoxygenase catalysis [41]. The presence of benzaldehyde was statistically higher in the Syrah sparkling wine, as compared to the others. But in general, the chromatographic areas was lower than 0.4 in the headspace for all the sparkling wines of the SFV (Table 3). The volatile phenols can have a negative effect on the global aroma of wines, providing aromas described as \"animal\", \"horse sweat\", \"leather\", or \"medicinal\". However, in low concentrations they contribute to increasing the aroma complexity [9]. The presence of this type of volatile compound in the sparkling wines of the SFV was discrete, ranging from 0.051 (Chenin Blanc and CB+SY-W) to 0.067 (Syrah) in the chromatographic area (Table 3). The terpen are responsible for the younger and floral aromas of wines and they are related to the varietal aromas of certain groups of varieties, mainly muscats [8; 14]. In this study, the only terpene that was tentatively identified was carvone, which presented the highest normalized chromatographic area in CB+SY-W and Chenin Blanc sparkling wines (Table 3). Despite being related to varietal aromas, terpen are not frequently identified in wines from Chenin Blanc and Syrah varieties. [PERSON] et al. [24] found two terpen in Chenin Blanc wines and [PERSON] et al. [42] identified four in Syrah wines. In order to link volatile compounds and identify main parameters contributing to discriminate four different sparkling wines from SFV, principal component analysis (PCA) was applied in the average of three replicates of the results obtained with 1D-GC/qMS (Table 3), from each one of the four sparklings evaluated. The PCA (Figure 1) showed that two PCs explained 81.57% of total variability of the data, separating the sparkling wines samples according to the grape varieties and blends used. The first principal component (PC1) explained 60.19% of the total variability from GC-MS data, separating the sparkling wines produced from Chemin Blanc, located in the positive side of the \(X\)-axis, from the Syrah sparkling wine located in the negative side of the \(X\)-axis (Figure 1).