## 3 Results
#### 3.2.3 Main Oenological Volatile Compounds  
Regarding the main volatile compounds (Table 4), significant differences were shown. Both sequential fermentations showed significantly higher amounts of esters and higher alcohols (with the exclusion of isoamylic alcohol) and terpenes in comparison with pure fermentation. The sequential fermentation of _T. delbrueckii_ DiSVA 130/_S. cerevisiae_ DiSVA 709 was characterized by ethyl acetate, isoamyl acetate, isobutanol amyl alcohol, linalool, and nerol production, while _T. delbrueckii_ ALPHA(r)/_S. cerevisiae_ DiSVA 709 exhibited significantly higher amounts of ethyl butyrate, ethyl lexanoate, isoamyl acetate, \(\beta\)-phenyl ethanol, phenyl ethyl acetate, linalool, and geraniol. However, the level of terpenes was lower than the threshold values in wines for these compounds. \begin{table}
\begin{tabular}{c c c c c c} \hline  & _S. cerevisiae_ & & _T. delbrueckii_ DiSVA & & _T. delbrueckii_ & \\  & **DiSVA 709** & **OAV** & **130/S. cerevisiae** & **OAV** & **ALPHA®_. cerevisiae_ & **OAV** \\  & **(mg/L)** & & **DiSVA 709 (mg/L)** & & **DiSVA 709 (mg/L)** & \\ \hline \multicolumn{5}{c}{**ESTERS**} \\ \hline Ethyl butyrate & & & & & \\  (0.02) & 0.40 \(\pm\) 0.10 b  & 1 & 0.31 \(\pm\) 0.01 c  & 0.77 & 0.52 \(\pm\) 0.19 a  & 1.3 \\ Ethyl acetate & & & & \\  (7.50) & 26.42 \(\pm\) 4.29 b  & 2.2 & 59.88 \(\pm\) 2.14 a  & 4.99 & 33.67 \(\pm\) 6.71 b  & 2.8 \\ Ethyl hexanoate & 2.76 \(\pm\) 0.33 b  & 34.5 & 2.90 \(\pm\) 0.41 ab  & 36.25 & 3.39 \(\pm\) 0.35 a  & 42.37 \\ Isoamyl acetate & (0.03) & 0.90 \(\pm\) 0.01 b  & 5.62 & 0.95 \(\pm\) 0.08 a  & 4.06 & 1.03 \(\pm\) 0.04 a  & 6.43 \\ Phenylethyl & & & & & \\   acetate & 0.08 \(\pm\) 0.01 c  & 1.09 & 0.74 \(\pm\) 0.16 b  & 10.13 & 0.98 \(\pm\) 0.08 a  & 13.42 \\  & (0.25) & & & & \\ \hline \multicolumn{5}{c}{**ALCOHOLS**} \\ \hline n-propanol & & & & & \\  (9.0) & 37.01 \(\pm\) 3.09 a  & 0.12 & 39.25 \(\pm\) 1.40 a  & 0.13 & 38.73 \(\pm\) 0.79 a  & 0.12 \\ Isobutanol & & & & & \\  (40.0) & 15.38 \(\pm\) 1.72 b  & 0.38 & 26.67 \(\pm\) 5.20 a  & 0.66 & 11.92 \(\pm\) 3.30 c  & 0.30 \\ Amyl alcohol & & & & & \\  (12.2) & 12.99 \(\pm\) 0.26 b  & 0.20 & 39.76 \(\pm\) 8.28 a  & 0.62 & 14.33 \(\pm\) 3.77 b  & 0.22 \\ \hline \end{tabular}
\end{table} 
Table 4: The main volatile compounds of pure fermentation of _S. cerevisiae_ DiSVA 709 and sequential fermentation with _T. delbrueckii_ DiSVA 130 and ALPHA® commercial strain (mg/L). The threshold values are reported in brackets (mg/L). OAV: odor activity value. ND = not detected. Data with different superscript letters (a,b,c) within each column are significantly different (Duncan tests; \(p<0.05\)). \begin{table}
\begin{tabular}{c c c c c} \hline  & **Ethanol** & **Total Acidity** & **Volatile Acidity** & **Malic Acid** \\  & **(\%\%/\(\
u\))** & **(g/L)** & **(g/L)** & **(g/L)** \\ \hline _S. cerevisiae_ DiSVA 709 & 14.43 \(\pm\) 0.00 a  & 5.52 \(\pm\) 0.02 a  & 0.25 \(\pm\) 0.06 a  & 1.2 \(\pm\) 0.00 a  \\ _T. delbrueckii_ DiSVA 130/_S. cerevisiae_ DiSVA 709 & 13.77 \(\pm\) 0.10 b  & 5.55 \(\pm\) 0.14 a  & 0.23 \(\pm\) 0.01 a  & 1.2 \(\pm\) 0.14 a  \\ _T. delbrueckii_ ALPHA®_S_. cerevisiae_ DiSVA 709 & 13.71 \(\pm\) 0.02 b  & 5.52 \(\pm\) 0.06 a  & 0.25 \(\pm\) 0.03 a  & 1.1 \(\pm\) 0.00 a  \\ \hline \end{tabular}
\end{table} 
Table 3: The main analytical characteristics of pure fermentation of _S. cerevisiae_ DiSVA 709 and sequential fermentation with _T. delbrueckii_ DiSVA 130 and ALPHA® commercial strain. Data with different superscript letters (a,b) within each column are significantly different (Duncan tests; \(p<0.05\)). Sensory Analysis of Verdicchio Wines inoculated with S. cerevisiae DiSVA 709, T. delbrueckii DiSVA 130/S. cerevisiae DiSVA 709, and T. delbrueckii ALPHA\({}^{\circledR}\)/S. cerevisiae DiSVA 709  
The wines obtained by the second fermentation trials (without SO\({}_{2}\) added) were evaluated by sensory analysis to establish the role and the influence of _T. delbrueckii_ in their aroma features and complexity.