## 3 Results and Discussion
### Volatile Aroma in Grape Juice and Skin
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline  & \multicolumn{4}{c}{**NS**} & \multicolumn{4}{c}{**SKIN BND (ug kg \({}^{-1}\))**} & \multicolumn{4}{c}{**JS**} & \multicolumn{4}{c}{**JUICE BND(ug kg \({}^{-1}\))**} & \multicolumn{4}{c}{**SS**} & \multicolumn{4}{c}{**SS**} \\  & **max** & **min** & **mean** & **max** & **min** & **mean** & **mean** & **max** & **min** & **mean** & **max** & **min** & **mean** & **mean** \\ \hline
2-Methyl-2-butanol* & 47.0 & 7.9 & 26.5 & 49.0 & 15.3 & 30.0 \({}^{\rm m}\) & 22.4 & 30.6 & 11.0 & 21.3 \({}^{\rm m}\) & 42.1 & 13.8 & 252.2 \({}^{\rm m}\) & 17.3 \\ Buyl acetate & 36.8 & 0.00 & 20.9 \({}^{\rm m}\) & 52.4 & 4.3 & 30.8 \({}^{\rm m}\) & 26.7 & 50.0 & 4.7 & 23.3 \({}^{\rm m}\) & 46.2 & 7.5 & 26.3 \({}^{\rm m}\) & 43.4 \\ Buiden & 19.0 & 0.00 & 13.3 \({}^{\rm m}\) & 28.0 & 6.1 & 16.8 \({}^{\rm m}\) & 15.2 & 18.9 & 6.8 & 14.1 \({}^{\rm m}\) & 31.8 & 11.0 & 17.5 \({}^{\rm m}\) & 14.1 \\ Pen-3-en-20-1* & 93.7 & 52.1 & 79.6 \({}^{\rm m}\) & 124.2 & 15.0 & 79.9 \({}^{\rm m}\) & 84.4 & 57.7 & 10.1 & 44.7 \({}^{\rm m}\) & 65.5 & 27.9 & 48.2 \({}^{\rm m}\) & 38.3 \\ Limoneme* & 4.8 & 0.00 & 2.1 \({}^{\rm m}\) & 5.5 & 0.3 \({}^{\rm m}\) & 0.3 \({}^{\rm m}\) & 0.5 & 7.2 & 0.2 & 2.8 \({}^{\rm m}\) & 6.3 & 0.9 & 3.4 \({}^{\rm m}\) & 3.4 \\ Nonanal & 162.1 & 0.20 & 10.5 \({}^{\rm m}\) & 166.6 & 8.3 & 96.9 \({}^{\rm m}\) & 39.9 & 150.7 & 10.8 & 71.9 \({}^{\rm m}\) & 149.8 & 22.3 & 90.6 \({}^{\rm m}\) & 127.6 \\ Prepenoid * & 12.0 & 0.00 & 5.7 \({}^{\rm m}\) & 16.3 & 0.9 \({}^{\rm m}\) & 7.7 \({}^{\rm m}\) & 0.00 & 9.5 & 0.4 & 4.7 \({}^{\rm m}\) & 15.4 & 2.4 & 8.1 \({}^{\rm m}\) & \\
2-Ethyl-1-heanol & 147.7 & 37.2 & 77.0 & 70.0 & 140.3 & 3.6 \({}^{\rm m}\) & 84.0 \({}^{\rm m}\) & 38.4 \({}^{\rm m}\) & 11.5 & 4.5 & 57.2 \({}^{\rm m}\) & 129.0 & 22.2 & 78.6 \({}^{\rm m}\) & 86.3 \\ Benataldehyde & 246.2 & 1.9 & 106.2 \({}^{\rm m}\) & 305.5 & 11.8 & 178.3 \({}^{\rm m}\) & 17.4 & 24.8 & 12.7 & 105.2 \({}^{\rm m}\) & 221.8 & 17.5 \({}^{\rm m}\) & 137.5 \({}^{\rm m}\) & 196.2 \\ Acetophenone & 13.3 & 4.6 & 7.9 \({}^{\rm m}\) & 21.1 & 1.3 & 12.5 \({}^{\rm m}\) & 6.4 & 11.3 & 1.8 & 6.7 \({}^{\rm m}\) & 14.5 & 4.5 & 9.5 \({}^{\rm m}\) & 9.1 \\ \(\alpha\)-Terphenyl & 17.1 & 3.0 & 8.8 \({}^{\rm m}\) & 20.0 & 0.00 & 10.8 \({}^{\rm m}\) & 3.6 & 13.2 & 0.9 & 6.6 \({}^{\rm m}\) & 14.6 & 1.9 & 88.8 \({}^{\rm m}\) & 13.4 \\ Benaryl alcohol & 216.9 & 9.4 & 80.9 \({}^{\rm m}\) & 282.3 & 5.3 & 166.7 \({}^{\rm m}\) & 10.2 & 282.3 & 3.9 & 121.6 \({}^{\rm m}\) & 227.7 & 7.6 & 126.0 \({}^{\rm m}\) & 190.2 \\ \(\beta\)-Terphenylethanol & 6.9 & 0.00 & 3.5 \({}^{\rm m}\) & 10.3 & 0.2 & 48.9 \({}^{\rm m}\) & nd & nd & nd & nd & nd & nd & nd \\ Total VOCs & 507.5 & & & & & & & & & & & & & \\ \hline NS-samples collected in north Sardinia area (\(n=6\)); CS-samples collected in central Sardinia area (\(n=7\)); SS-sample collected in south Sardinia area (\(n=1\)); nd-not detected; tr-trace \({}^{\rm m}\); not significant. Data are the mean of three replicates. *- quantified with a calibration curve of a compound of the same chemical class as reported in Table 2. & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 4: Range and average levels of volatile glyco-coeriugated aroma compounds in the skin and pulp of Cannonau grapes collected in Sardinia. The main monoterpene detected in Cannonau grapes was \(\alpha\)-terpineol, ranging from 2.6 to 15.7 \(\mu\)g kg\({}^{-1}\) and 0 to 20.0 \(\mu\)g kg\({}^{-1}\) in skins; and 0.04 to 14.6 \(\mu\)g kg\({}^{-1}\) and 0.9 to 14.6 \(\mu\)g kg\({}^{-1}\) in juice for the free and bound forms, respectively. In line with a previous study [35], the glycosylated monoterpenes were found to be more abundant than the respective compounds in the free form. The average total amount of terpenoids (\(\alpha\)-terpineol, limonene, and the unidentified terpenoid) present in grape skins accounted for 28.6 \(\mu\)g kg\({}^{-1}\) (free and bound forms combined) in the NS samples, and 31.1 \(\mu\)g kg\({}^{-1}\) (free and bound forms combined) in the CS samples.