## 2 Results and Discussion
### Volatile Organic Compounds
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Volatile** & **RI\({}_{\text{Exp}}\) \({}^{\ast}\)** & **RI\({}_{\text{Lib}}\) \({}^{\ast\ast}\)** & **BLP** & **C** & **B2.5** & **B5** & **Odour** \\  & & & & & & & **Description *** \\ \hline _Aldehydes_ & & & & & & & \\ \multicolumn{1}{c}{Propanal} & 817 & 801 & 4.85 \(\pm\) 0.45 & ND *** & 5.17 \(\pm\) 0.55 & 5.89 \(\pm\) 0.25 \({}^{\text{a}}\) & fresh, fruity, malty \\ \multicolumn{1}{c}{Butanal} & 891 & 883 & 2.01 \(\pm\) 0.13 & ND & ND & 0.40 \(\pm\) 0.04 & malty, sweaty \\ \multicolumn{1}{c}{2-Methylbutanal} & 922 & 915 & 5.48 \(\pm\) 0.42 & ND & 0.19 \(\pm\) 0.02 \({}^{\text{b}}\) & 3.00 \(\pm\) 0.03 \({}^{\text{a}}\) & malty \\ \multicolumn{1}{c}{3-Methylbutanal} & 927 & 920 & 7.87 \(\pm\) 0.49 & ND & 0.41 \(\pm\) 0.05 \({}^{\text{a}}\) & 0.54 \(\pm\) 0.09 \({}^{\text{a}}\) & malty \\ \multicolumn{1}{c}{Pentanal} & 987 & 983 & ND & 2.22 \(\pm\) 0.19 \({}^{\text{b}}\) & 2.74 \(\pm\) 0.15 \({}^{\text{a}}\) & 2.98 \(\pm\) 0.08 \({}^{\text{a}}\) & green, fatty, mouldy \\ \multicolumn{1}{c}{Hexanal} & 1087 & 1093 & 50.83 \(\pm\) 0.98 & 53.66 \(\pm\) 4.91 \({}^{\text{a}}\) & 31.91 \(\pm\) 1.53 \({}^{\text{b}}\) & 28.05 \(\pm\) 1.98 \({}^{\text{b}}\) & green grass, fatty \\ \multicolumn{1}{c}{(\(E\))-2-Methyl-2-} & 1097 & 1098 & 12.81 \(\pm\) 1.15 & ND & 0.53 \(\pm\) 0.28 \({}^{\text{b}}\) & 2.14 \(\pm\) 0.31 \({}^{\text{a}}\) & green, fruity, aromatic \\ \multicolumn{1}{c}{(\(E\))-2-Pentenal} & 1139 & 1140 & 20.12 \(\pm\) 0.2 & 0.13 \(\pm\) 0.00 \({}^{\text{c}}\) & 1.49 \(\pm\) 0.11 \({}^{\text{b}}\) & 2.24 \(\pm\) 0.07 \({}^{\text{a}}\) & oily, fatty, fruity \\ \multicolumn{1}{c}{Heptanal} & 1189 & 1188 & ND & 5.29 \(\pm\) 0.39 \({}^{\text{a}}\) & 3.97 \(\pm\) 0.61 \({}^{\text{b}}\) & 4.78 \(\pm\) 0.15 \({}^{\text{a}}\) & fatty, citrus-like \\ \multicolumn{1}{c}{(\(E\))-2-Hexenal} & 1227 & 1220 & 30.85 \(\pm\) 0.53 & 1.38 \(\pm\) 0.11 \({}^{\text{c}}\) & 4.01 \(\pm\) 0.22 \({}^{\text{b}}\) & 5.28 \(\pm\) 0.21 \({}^{\text{a}}\) & green apple-like, bitter \\ \multicolumn{1}{c}{(\(Z\))-4-Heptanal} & 1251 & 1235 & 13.92 \(\pm\) 0.07 & ND & 0.87 \(\pm\) 0.24 \({}^{\text{b}}\) & 1.45 \(\pm\) 0.16 \({}^{\text{a}}\) & fish-like, train oil-like \\ \multicolumn{1}{c}{Octanal} & 1293 & 1291 & 3.38 \(\pm\) 0.11 & 1.73 \(\pm\) 0.29 \({}^{\text{b}}\) & 5.48 \(\pm\) 0.62 \({}^{\text{a}}\) & 4.63 \(\pm\) 0.40 \({}^{\text{a}}\) & citrus-like, green \\ \multicolumn{1}{c}{Nonanal} & 1398 & 1390 & 7.47 \(\pm\) 0.13 & 2.39 \(\pm\) 0.33 \({}^{\text{b}}\) & 4.01 \(\pm\) 0.29 \({}^{\text{a}}\) & 4.88 \(\pm\) 0.65 \({}^{\text{a}}\) & citrus-like, soapy \\ \multicolumn{1}{c}{(\(E\)-2-Octenal} & 1440 & 1437 & 2.76 \(\pm\) 0.1 & 3.01 \(\pm\) 0.18 \({}^{\text{b}}\) & 6.59 \(\pm\) 0.66 \({}^{\text{a}}\) & 6.52 \(\pm\) 0.77 \({}^{\text{a}}\) & fatty, nutty \\ \multicolumn{1}{c}{(\(E\),\(E\)-2-4-} & 1477 & 1497 & 26.15 \(\pm\) 0.47 & ND & 1.04 \(\pm\) 0.11 \({}^{\text{b}}\) & 1.65 \(\pm\) 0.18 \({}^{\text{a}}\) & green, fatty, flowery \\ \multicolumn{1}{c}{Heptadien} & 1538 & 1530 & 37.59 \(\pm\) 0.92 & 2.26 \(\pm\) 0.94 \({}^{\text{a}}\) & 1.32 \(\pm\) 0.10 \({}^{\text{a}}\) & 1.95 \(\pm\) 0.34 \({}^{\text{a}}\) & bitter almond-like \\ \multicolumn{1}{c}{(\(E\))-2-Nonenal} & 1547 & 1543 & ND & 1.96 \(\pm\) 0.15 \({}^{\text{c}}\) & 3.78 \(\pm\) 0.45 \({}^{\text{b}}\) & 5.10 \(\pm\) 0.48 \({}^{\text{a}}\) & fatty \\ \multicolumn{1}{c}{(\(E\),\(Z\))-2,6-} & 1598 & 1596 & 2.05 \(\pm\) 0.71 & ND & 0.26 \(\pm\) 0.04 \({}^{\text{b}}\) & 0.55 \(\pm\) 0.06 \({}^{\text{a}}\) & green, cucumber-like \\ \multicolumn{1}{c}{Nonadien} & 1661 & 1648 & 4.71 \(\pm\) 0.78 & ND & 0.36 \(\pm\) 0.06 \({}^{\text{b}}\) & 0.53 \(\pm\) 0.04 \({}^{\text{a}}\) & herbal \\ \multicolumn{1}{c}{(\(E\),\(E\)-2-4-} & 1716 & 1691 & ND & 0.29 \(\pm\) 0.03 \({}^{\text{a}}\) & 0.11 \(\pm\) 0.04 \({}^{\text{b}}\) & 0.10 \(\pm\) 0.04 \({}^{\text{b}}\) & fatty, green \\ \multicolumn{1}{c}{(\(E\),\(E\))-2,4-} & 1779 & 1786 & ND & 0.64 \(\pm\) 0.07 \({}^{\text{a}}\) & 0.88 \(\pm\) 0.07 \({}^{\text{a}}\) & 0.84 \(\pm\) 0.09 \({}^{\text{a}}\) & fatty, deep-fried \\ \multicolumn{1}{c}{Redones} & & & & & & & \\ \multicolumn{1}{c}{Acetone} & 838 & 813 & 8.08 \(\pm\) 0.32 & ND & 0.30 \(\pm\) 0.09 Although the VOCs in Brassica vegetables have been widely studied [38; 39; 40; 41], in this study, the profile of broccoli leaves was analysed for the first time.