## 2 Results and Discussion
### Multivariate Analyses of Metabolites in the Five Rice Varieties
\begin{table}
\begin{tabular}{l c c c} \hline
**Differential Metabolites** & **RT [min]** & _p-Value_ & **VIP** \\ \hline
5-Ethyl-2-decen-4-one & 23.50 & 0.000312 & 1.85 \\
1-(3,3-Dimethyloxiranyl)ethanone & 13.61 & 0.004344 & 1.84 \\
3-Methyl-6-ethyl-2,4-dioxadecane & 21.00 & \(1.83\times 10^{-6}\) & 1.84 \\
3-Methyl-2-butenal- & 10.58 & \(1.01\times 10^{-5}\) & 1.84 \\ Mei vs. PU & (2-Methylcyclopentene & 6.37 & \(3.01\times 10^{-8}\) & 6.83 \\
2,6,7-Trimethyldecane & 6.03 & 0.048495 & 4.75 \\
2,2-Dichloroethanol & 21.64 & 0.000132 & 3.81 \\
1,2-Dimethoxybenzene & 24.32 & \(5.19\times 10^{-9}\) & 3.79 \\
2-Butyl-2-octenal & 23.12 & \(1.36\times 10^{-7}\) & 3.69 \\ Tetramethylpyrazine & 18.45 & 0.017066 & 3.35 \\
2-Isopropyl-5-methyl-9-methylenebicyclo[4.4.0]dec-1-ene & 21.43 & 0.044206 & 3.31 \\
1-Ethyl-5-methylcyclopentene & 4.59 & \(1.84\times 10^{-6}\) & 3.14 \\
4,8-Dimethyluthemat & 10.76 & 0.092829 & 3.04 \\ Docceamenethylcyclohexassiloxane & 15.17 & \(1.00\times 10^{-9}\) & 3.01 \\
3-Isopropyl-1,1,7,7,7-hexamethyl-3,5,5-tris(trimethylsiloxy)tetrasiloxane & 19.53 & \(1.52\times 10^{-8}\) & 2.98 \\ Acetoin & 13.11 & \(2.78\times 10^{-6}\) & 2.86 \\ Propanoic acid butyl ester & 8.96 & 0.000923 & 2.78 \\ _trans_-2-(2-Propynyloxy)cyclopentanol & 24.23 & 0.000126 & 2.49 \\ n-Butylbenzene- & 13.93 & 0.071259 & 2.45 \\
2-Propenoic acid butyl ester & 10.00 & 0.000325 & 2.32 \\
2-2-Octen-1-ol & 21.96 & \(6.04\times 10^{-6}\) & 2.28 \\
1-Ethenylazirdine & 5.45 & \(6.06\times 10^{-7}\) & 2.26 \\ Acetic acid butyl ester & 6.97 & \(1.03\times 10^{-8}\) & 2.22 \\
3-Octen-2-one & 16.60 & 0.000309 & 2.22 \\
5-Oxotetrahydrofuran-2-carboxylate acid & 21.35 & 0.00012 & 2.21 \\
5-Ethyl-2-decen-4-one & 23.50 & \(3.86\times 10^{-5}\) & 2.21 \\
6,10,14-Trimethyl-pentadecan-2-ol & 26.30 & \(1.48\times 10^{-5}\) & 2.14 \\
5-Methyl-2-(1-methylethyl)-2-cyclohexen-1-one & 23.68 & 0.000157 & 2.13 \\
3-Nonen-2-one & 19.32 & 0.036233 & 2.10 \\
2-Ethyl-2-(hydroxymethyl)-1,3-propanediol & 14.11 & \(1.26\times 10^{-8}\) & 2.09 \\
2,5-Dimethyl-2,4-hexadiene & 5.92 & \(1.18\times 10^{-5}\) & 2.03 \\ Pentanoic acid & 25.13 & 0.000287 & 1.98 \\ Pentanal & 4.54 & \(3.83\times 10^{-5}\) & 1.97 \\
2-Methyldecane & 7.90 & 0.03382 & 1.88 \\ DAO vs. HU & 21.43 & 0.021135 & 5.63 \\
2-Isopropyl-5-methyl-9-methylenebicyclo[4.4.0]dec-1-ene & 21.43 & 0.021135 & 5.63 \\
1(5-_exo_)-2-Methyl-3-methylene-2-(4-methyl-3-pentenyl)bicyclo[2.2.1]heptane & 22.69 & \(1.76\times 10^{-6}\) & 4.87 \\ Butyl benzoate & 27.34 & 5.09 \(\times\) 10\({}^{-6}\) & 4.46 \\
2-Acetyl-1-pyrroline & 14.64 & \(3.82\times 10^{-7}\) & 4.38 \\
4,8-Dimethylundecane & 10.76 & 0.127631 & 3.90 \\ _trans_-Verbenyl caprate & 14.35 & 0.016663 & 3.87 \\
2-Butyl-2-octenal & 23.12 & \(5.95\times 10^{-5}\) & 3.24 \\
1,3-Dimethoxybenzene & 24.80 & \(2.90\times 10^{-8}\) & 3.23 \\ Dibtuoxymethane & 11.28 & \(3.72\times 10^{-8}\) & 3.06 \\
1-Ethenylazirdine & 5.45 & \(1.63\times 10^{-5}\) & 3.05 \\ Carbon monoxide & 2.25 & 0.041224 & 3.05 \\ Sulfurous acid dodecyl pentyl ester & 16.81 & 0.000566 & 3.03 \\ (E)-2-Hexenal & 11.16 & 0.001103 & 3.02 \\ DL-2-Phenyl-1,2-propanediol & 25.13 & 0.000277 & 3.02 \\
1-(1H-Pyrrol-2-yl)ethanone & 29.47 & \(1.36\times 10^{-6}\) & 2.97 \\
2-Methyldecane & 7.90 & 0.005357 & 2.96 \\
17.66 & \(1.40\times 10^{-6}\) & 2.79 \\
6.03 & 0.289158 & 2.79 \\
27.52 & \(2.16\times 10^{-7}\) & 2.73 \\
13.11 & 0.005829 & 2.62 \\
19.32 & 0.030047 & 2.58 \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._