## 3 Results and Discussion
### Evaluation of SAFE, SDE and SPME Extracts by GC\(\times\)GC

Table 2: Volatile compounds identified by GC\(\times\)GC-ToFMS (tentative identification using NIST mass spectra library) from SAFE. SDE and SPME extracts. nd: not determined. Quantities expressed as percentage value using two decimal points. Compounds with peak area % \(>\) 0.01% shown. Compounds listed according to their increasing molecular weight (MW). Figure 1: Main groups of volatile compounds in raw broccoli obtained using different extraction techniques. Graphs created based on area % of peaks identified using two-dimensional gas chromatography time-of-flight mass spectrometry (GC\(\times\)GC-ToFMS). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Compound** & **Molecular Weight** & **SDE \%** & **SAFE \%** & **SPME \%** \\ \hline sulfide, allyl methyl & 88 & 0.02 & nd & nd \\ dimethyl sulfone & 94 & 0.05 & 1.62 & 0.51 \\ disulfide, dimethyl & 94 & 5.50 & 3.19 & 13.00 \\ pyrazine. methyl- & 94 & 0.40 & 0.01 & nd \\
2,4-hexadien, (E,E)- & 96 & 0.60 & 0.28 & 0.19 \\ furan, 2-ethyl- & 96 & 1.84 & 0.65 & 10.29 \\ furfurral & 96 & 3.76 & nd & nd \\ hexanentirile & 97 & 0.09 & 0.06 & 0.19 \\ pentanenitrile, 4-methyl- & 97 & s & 0.01 \\
2-hexanal, (E)- & 98 & 1.39 & 1.06 & 3.63 \\
3-hexanal & 98 & nd & 0.55 & 0.57 \\ thiophene, 2-methyl- & 98 & 0.05 & 0.04 & 0.03 \\ thiophene, 3-methyl- & 98 & 0.02 & nd & nd \\
2-hexen-1-ol, (E)- & 100 & 8.51 & 6.02 & 0.02 \\
3-hexen-1-ol, (Z)- & 100 & 5.62 & 3.51 & 23.58 \\ hexanal & 100 & 0.52 & 0.31 & 3.10 \\ isopropyl isothiamate & 101 & 0.03 & nd & nd \\
1-hexanol & 102 & 9.70 & 6.48 & 4.91 \\ S-methyl propanaethioate & 104 & 0.03 & nd & nd \\ benzaldehyde & 106 & 0.51 & 1.09 & 0.46 \\ pyrazine, ethenyl- & 106 & 0.02 & nd & nd \\ hexanedinitrile & 108 & 0.02 & 0.01 & nd \\ pyrazine, 2.3-dimethyl- & 108 & 0.10 & nd & nd \\ pyrazine, 2.5-dimethyl- & 108 & 0.20 & nd & nd \\
2,4-heptotal, (E,E)- & 110 & 2.05 & 1.21 & 0.26 \\ furan, 2-ethyl- & 110 & 0.10 & nd & 0.01 \\ furan, 2-propyl- & 110 & 0.32 & nd & 0.02 \\ hexanentirile, 5-methyl- & 111 & 0.10 & 0.03 & 0.28 \\
2(5H)-furanone, 5-ethyl- & 112 & 0.71 & 1.65 & 0.14 \\
3-hepten-2-one & 112 & 0.52 & 0.04 & nd \\ thiophene, 2-ethyl- & 112 & 0.46 & 0.38 & 2.87 \\
1-butene, 4-isothiocyanato- & 113 & 1.75 & 9.83 & 0.01 \\ heptanal & 114 & 0.45 & 0.08 & 0.15 \\ octane & 114 & 0.26 & nd & nd \\ butane, 1-isothiocyanato- & 115 & nd & nd & 0.01 \\ butane, 2-isothiocyanato- & 115 & 0.10 & nd & nd \\ butanenitrile, 4-(methylthio)- & 115 & 0.06 & nd & nd \\ isobutyl isothiamate & 115 & nd & nd & 0.01 \\ benzyl nitrite & 117 & 0.13 & 0.21 & 0.05 \\ indlo & 117 & 1.67 & 0.03 & nd \\ butane Antibiotic acid, S-methyl ester & 118 & 0.04 & nd & nd \\ benzeneacetaldehyde & 120 & 0.69 & 0.64 & 0.72 \\ pyrazine, (1-methyleth)- & 120 & 0.01 & nd & nd \\ phenylethyl alcohol & 122 & nd & 0.66 & 0.17 \\ pyrazine, trimethyl- & 122 & 0.05 & nd & nd \\
1,2,4-trithiolane & 124 & 0.11 & 1.33 & 0.06 \\
2,4-octadien, (E,E)- & 124 & 0.66 & nd & nd \\ cyclohexane, isocyanoato- & 125 & 0 & 0.01 & nd \\ butane, 1-isothiocyanato- 3-methyl- & 126 & 0 & 0.01 & 0.01 \\ dimethyl trisulfide & 126 & 2.33 & 2.57 & 3.37 \\ S-methyl methanethiosulfphone & 126 & 2.80 & 9.53 & 0.08 \\ cyclopentyl isothiamate & 127 & 0.01 & 0.06 & nd \\ hexane, 1-isocyanato- & 127 & nd & 0.03 & 0.01 \\
3-hexen-1-ol, formate. (Z)- & 128 & 2.13 & 0.77 & 0.82 \\ butanoic acid, 2-propenyl ester & 128 & nd & 0.58 & nd \\ heptane, 2.4-dimethyl- & 128 & nd & 0.28 & nd \\ octanal & 128 & 0.10 & nd & nd \\
2-methylbutyl isothiamate & 129 & 0.14 & nd & nd \\ pentanenitrile, 5-(methylthio)- & 129 & nd & 0.51 & nd \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._Analysis of volatiles in plants is a complex issue. The composition of volatile metabolites is unstable and dependent on many factors, such as storage conditions, cultivars or technological processes [16]. This makes it extremely important to choose an appropriate technique to isolate those components. Ideally, this technique should not modify the volatile composition by high temperature, long extraction times, etc.