# Construction of IsoVoc Database for the Authentication of Natural Flavours
## 3 Results and Discussion
### Authenticity Assessment of Commercial Samples
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Natural Compound**} & \multicolumn{3}{c}{**Synthetic Compound**} & \multicolumn{3}{c}{**Detectable Synthetic**} \\ \cline{2-9}
**Aroma Compound** & **Min** & **Max** & **Median** & **Min** & **Max** & **Median** & **x** & **x** \\ \cline{2-9}  & \multicolumn{3}{c}{\(\delta^{13}\)C (\%)**} & \multicolumn{3}{c}{\(\delta^{13}\)C (\%)} & \multicolumn{3}{c}{**50\%**} & \multicolumn{3}{c}{**100\%**} \\  & \multicolumn{3}{c}{} & \multicolumn{3}{c}{} & \multicolumn{3}{c}{**Threshold**} & \multicolumn{3}{c}{**Threshold**} \\ \hline \(\gamma\)-decalactone & \(-37.7\) & \(-28.7\) & \(-31.5\) & \(-26.9\) & \(-24.4\) & \(-26.1\) & \(0.52\) & \(0.83\) \\ \(1\)-butanol & \(-44.5\) & \(-40.8\) & \(-42.3\) & \(-31.4\) & \(-31.4\) & \(-31.4\) & \(0.14\) & \(0.28\) \\ \(1\)-hexanol & \(-43.7\) & \(-30.2\) & \(-39.4\) & \(-24.4\) & \(-24.4\) & \(-24.4\) & \(0.61\) & \(0.70\) \\ \(1\)-octanol & \(-36.5\) & \(-31.5\) & \(-34.9\) & \(-29.2\) & \(-28.8\) & \(-29.0\) & \(0.57\) & \(0.68\) \\ \(2\)-heptanone & \(-27.6\) & \(-20.7\) & \(-24.8\) & \(-29.4\) & \(-29.4\) & \(-29.4\) & \(0.61\) & \(0.80\) \\ \((\)E)-2-hexen-1-olololollinearity & \(-38.8\) & \(-32.2\) & \(-34.9\) & \(-30.2\) & \(-28.0\) & \(-30.1\) & \(0.56\) & \(0.78\) \\ \((\)E)-2-hexen-1-ollinearity, acetate & \(-32.4\) & \(-29.5\) & \(-30.8\) & \(-37.0\) & \(-33.2\) & \(-35.1\) & \(0.37\) & \(0.78\) \\ acetic acid & \(-31.3\) & \(-28.1\) & \(-30.2\) & \(-42.0\) & \(-42.0\) & \(-42.0\) & \(0.09\) & \(0.23\) \\ benzaldehyde & \(-35.4\) & \(-28.0\) & \(-31.3\) & \(-26.0\) & \(-25.3\) & \(-25.7\) & \(0.59\) & \(0.79\) \\ butyl acetate & \(-40.1\) & \(-30.4\) & \(-35.8\) & \(-28.6\) & \(-28.6\) & \(-28.6\) & \(0.75\) & \(0.84\) \\ butyl butyrate & \(-41.4\) & \(-32.1\) & \(-36.8\) & \(-26.8\) & \(-26.8\) & \(-26.8\) & \(0.47\) & \(0.64\) \\ ethyl \(2\)-methyl butyrate & \(-34.3\) & \(-27.0\) & \(-29.3\) & \(-27.0\) & \(-24.7\) & \(-25.8\) & \(0.66\) & \(1.00\) \\ ethyl butyrate & \(-36.2\) & \(-28.5\) & \(-30.9\) & \(-25.7\) & \(-16.5\) & \(-21.1\) & \(0.24\) & \(0.73\) \\ hexanal & \(-45.0\) & \(-27.5\) & \(-38.0\) & \(-26.2\) & \(-25.3\) & \(-25.5\) & \(0.83\) & \(0.93\) \\ hexanoic acid & \(-29.9\) & \(-20.2\) & \(-25.8\) & \(-35.6\) & \(-35.6\) & \(0.42\) & \(0.63\) \\ hexyl \(2\)-methyl butyrate & \(-41.9\) & \(-31.0\) & \(-34.4\) & \(-27.6\) & \(-27.6\) & \(-27.6\) & \(0.49\) & \(0.76\) \\ hexyl butyrate & \(-40.0\) & \(-34.8\) & \(-36.2\) & \(-33.5\) & \(-33.5\) & \(-33.5\) & \(0.52\) & \(0.80\) \\ isoamyl acetate & \(-36.9\) & \(-30.2\) & \(-32.3\) & \(-28.5\) & \(-18.6\) & \(-23.5\) & \(0.24\) & \(0.80\) \\ methyl acetate & \(-38.2\) & \(-30.9\) & \(-34.3\) & \(-26.7\) & \(-26.7\) & \(-26.7\) & \(0.45\) & \(0.63\) \\ methyl butyrate & \(-33.8\) & \(-29.2\) & \(-31.1\) & \(-26.7\) & \(-26.7\) & \(-26.7\) & \(0.44\) & \(0.66\) \\ methyl hexanoate & \(-29.2\) & \(-24.1\) & \(-27.3\) & \(-35.9\) & \(-35.1\) & \(-35.5\) & \(0.23\) & \(0.47\) \\ propyl acetate & \(-37.9\) & \(-30.2\) & \(-33.4\) & \(-27.2\) & \(-27.2\) & \(-27.2\) & \(0.52\) & \(0.72\) \\ propyl propionate & \(-35.7\) & \(-29.6\) & \(-31.9\) & \(-25.5\) & \(-25.5\) & \(-25.5\) & \(0.36\) & \(0.60\) \\ \(\alpha\)-ionone & \(-34.2\) & \(-32.6\) & \(-33.4\) & \(-28.0\) & \(-21.6\) & \(-25.9\) & \(0.11\) & \(0.26\) \\ \(\beta\)-ionone & \(-33.4\) & \(-32.4\) & \(-32.7\) & \(-28.6\) & \(-25.6\) & \(-27.7\) & \(0.05\) & \(0.19\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The calculated fractions of added synthetic volatile organic compounds in commercial samples based on the isotope mass balance model. It is impossible to distinguish certain synthetic (petroleum-based) VOCs from natural ones since they can have a \(\delta^{13}\)C signature similar to that of a plant [42], which was also observed in our study for (E)-2-hexanal, 2-methylbutyl acetate, amyl acetate, E-neridol, ethyl acetate, ethyl hexanoate, hexyl acetate, and linalool.