# Nutritional Analysis of Red-Purple and White-Fleshed Pitaya (_Hylocereus_) Species
## 3 Results
### The Difference of Volatile Compounds between Red- and White-Fleshed Pitaya
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & & & & \\ \cline{3-8}
**RI** & **R.T.** & **Compound Name** & & & & & \\ \cline{3-8}  & & & & & & & \\ \cline{3-8}
1777 & 40.866 & Pentadecanol & - & - & 2.09 & - \\
1586 & 36.188 & Tridecycl alcohol & 8.96 & - & 4.68 & - \\ \hline  & & Total Alcohols & 15.5 & 10.86 & 9.37 & 37.17 \\ \hline  & & Terpenes & & & & \\
989 & 17.713 & 1-Limonene & 2.23 & 2.70 & - & - \\ \hline  & & Total Terpenes & 2.23 & 2.70 & 0 & 0 \\ \hline  & & Ketones & & & & \\
850 & 12.483 & 1-(2-furanyl)-Ethanone, & 3.24 & 4.11 & - & - \\
1456 & 32.730 & 5-hexyldihydro-2(3H)-Furanone, & - & - & - & 1.63 \\
1781 & 40.952 & diphenyl-methananone, & - & - & - & 1.08 \\
1714 & 39.369 & delta-dodecalactone & - & - & - & 1.30 \\ \hline  & & Total Ketones & 3.24 & 4.11 & 0 & 4.01 \\ \hline  & & Aldehydes & & & & \\
996 & 17.990 & 2 Octenal & - & - & 6.84 & - \\
1144 & 23.200 & 2,4 Monadenal & - & - & 1.56 & - \\
1192 & 24.783 & (E)- 2-Decenal & 2.2 & 10.13 & 2.76 & - \\
771 & 9.563 & 2-Furancarboxaldehyde & 17.37 & - & - & - \\
898 & 14.288 & (Z)-2-Heprenal & - & - & 5.11 & - \\
1100 & 21.724 & 3-methyl benzaldehyde & - & - & - & 137 \\
1011 & 18.540 & Caprylaldehyde & - & 2.08 & - & - \\
746 & 8.669 & Hexanal & 19.36 & 17.23 & 32.85 & - \\
1158 & 23.658 & 2(E)Nonneal & - & - & 2.75 & - \\
1044 & 19.721 & Nonanal & 2.23 & 8.13 & 4.05 & - \\
947 & 16.131 & Octanal & - & 6.34 & 1.8 & - \\
1289 & 27.865 & Trans-2-dodecenal & - & 7.69 & 0.98 & 0.57 \\
1173 & 24.159 & trans-2-Undecenal & - & - & - & 0.86 \\ \hline  & & Total Aldehydes & 41.16 & 51.60 & 58.70 & 2.80 \\ \hline  & & Esters & & & & \\
1643 & 37.628 & 1,2-Benzenzenederboxylic acid, & & & & \\  & & diethyl ester & - & - & - & 29.9 \\ \hline  & & Total Esters & 0 & 0 & 0 & 29.9 \\ \hline  & & Acids & & & & \\
1194 & 24.851 & Caprylic acid & - & 2.58 & - & - \\
1551 & 35.285 & Decanoic acid & - & - & 3.36 \\
1792 & 41.201 & Dodecanoic acid & - & - & 1.8 \\
1321 & 28.818 & Heptanoic acid & - & - & - & 0.81 \\
922 & 15.222 & Hexanoic acid & 8.07 & 5.84 & 6.74 & 6.58 \\
1194 & 24.852 & Nonanoic acid & 2.75 & - & 6.65 & - \\
1102 & 21.787 & Octanoic acid & 4.37 & 4.7 & 2.35 & 13.05 \\
1845 & 42.401 & Pentadecanoic acid & 12.14 & 6.46 & 3.53 & - \\
1658 & 37.993 & Tetradecanoic acid & 2.69 & - & - & - \\ \hline  & & Total Acids & 30.02 & 19.58 & 19.27 & 25.6 \\ \hline  & & Other compounds & & & & \\
767 & 9.430 & \(<\)1-methyl-\(>\)Piperidine & 2.63 & - & - & - \\
1438 & 32.206 & & 2,6-bis(1,-dimethylethyl)- & 5.2 & 8.49 & 3.05 & - \\
1582 & 36.100 & 1,1\({}^{*}\)-oxybis- octane, & - & - & 2.05 & 0.53 \\
1767 & 40.630 & 2,6,10,14-tetramethyl-hexadecane, & - & - & 5.2 & - \\
1248 & 26.573 & Tridecane & - & 2.64 & 2.37 & - \\ \hline  & & Total Other Compounds & 7.83 & 11.13 & 12.67 & 0.53 \\ \hline  & & & & & \\ \multicolumn{6}{c}{-: not detected.} \\ \end{tabular}
\end{table} 
Table 3: _Cont._The detailed compound names and content values are presented in Table 4. In the present study, we compared the extraction capabilities of both SPME fibers in red and white-fleshed pitaya. According to Table 4, the PDMS fiber extracted a total of 32 compounds and that of PDMS/DVB was 32. The PDMS fiber is preferred for the extraction of non-polar analytes, whereas the polar polyacrylate (PA) fiber is more suitable for the extraction of polar analytes. Mixed coating fibers, containing divinylbenzene (DVB) copolymers, templated resin (TPR) or carboxen (CAR) increase retention capacity. Thus, PDMS/DVB and CAR/DVB fibers can be more efficacious for the extraction of low molecular weight volatile compounds [76; 77]. Although both PDMS/DVB and PDMS fibers could extract a similar number of volatile compounds, the detailed compounds differ greatly, 12 volatile compounds were extracted by both PDMS and PDMS/DVB fibers; these compounds are described in Table 4.  
These results also showed that the PDMS and PDMS/DVB could independently extract 15 and 14 volatile compounds, respectively (Table 4). [PERSON] et al.