# Effects of Growth Parameters on the Analysis of _Aspergillus flavus_ Volatile Metabolites
## 3 Results and Discussion
### Effect of Temperature on MVOCs' Production  
Temperature has been proven to affect _A. flavus_ growth and aflatoxin production. MVOC production from _A. flavus_ was investigated using four different temperatures: 15, 30, 37 and 45 \({}^{\circ}\)C. Again, spores were grown on MEA media for seven days; the inoculated spore count was 10 \(\mu\)L of a 10\({}^{6}\) spores/mL mixture, and the MVOCs were collected with a CAR/PDMS SPME fiber for 5 h at \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compound Name**} & \multicolumn{4}{c}{**Peak Area (\(\times\)10\({}^{7}\)) a**} & \multirow{2}{*}{**\(p\)-Value b**} \\ \cline{3-3} \cline{5-7}  & & **High** & **Medium** & **Low** & **Toothpick** & \\ \hline
1 & Ethanol & 2.36 \(\pm\) 0.9 & 2.62 \(\pm\) 0.2 & 1.56 \(\pm\) 0.41 & 1.58 \(\pm\) 0.37 & 0.791 \\
2 & 1,4-Pentalidene & 6.99 \(\pm\) 2.39 & 7.98 \(\pm\) 3.29 & 8.89 \(\pm\) 2.49 & 0.91 \(\pm\) 0.13 & 0.010 \\
3 & 2-methylfuran & 4.4 \(\pm\) 1.13 & 5.25 \(\pm\) 0.9 & 4.8 \(\pm\) 1.24 & 2.26 \(\pm\) 0.52 & 0.009 \\
4 & 1-Propanol, 2-methyl- & 5.38 \(\pm\) 1.09 & 6.02 \(\pm\) 0.9 & 5.16 \(\pm\) 1.21 & 9.17 \(\pm\) 3.09 & 0.045 \\
5 & 3-methylbutanol & 1.83 \(\pm\) 0.63 & 2.35 \(\pm\) 0.56 & 1.93 \(\pm\) 0.45 & 2.7 \(\pm\) 1.02 & 0.061 \\
6 & 2-methylbutanol & 2.07 \(\pm\) 0.44 & 2.61 \(\pm\) 0.52 & 2.34 \(\pm\) 0.51 & 3.12 \(\pm\) 1.03 & 0.012 \\
7 & Toluene & 0.66 \(\pm\) 0.16 & 0.66 \(\pm\) 0.11 & 0.63 \(\pm\) 0.07 & 0.84 \(\pm\) 0.16 & 0.005 \\
8 & (\(-\))-Aristolene & 19.27 \(\pm\) 10.45 & 21.66 \(\pm\) 6.07 & 10.33 \(\pm\) 1.63 & 15.04 \(\pm\) 8.68 & 0.597 \\
9 & \(\beta\)-Elemene & 66.06 \(\pm\) 35.61 & 86.67 \(\pm\) 36.71 & 37.35 \(\pm\) 5.26 & 71.08 \(\pm\) 41.45 & 0.381 \\
10 & \(\alpha\)-Farnesene & 23.52 \(\pm\) 18.37 & 31.07 \(\pm\) 14.74 & 9.61 \(\pm\) 3.76 & 18.99 \(\pm\) 10.72 & 0.499 \\
11 & Cubenene & 19.48 \(\pm\) 13.56 & 28.81 \(\pm\) 13.4 & 7.86 \(\pm\) 3.78 & 27.33 \(\pm\) 14.48 & 0.363 \\
12 & \(\delta\)-Cadinene & 50.58 \(\pm\) 30.48 & 53.46 \(\pm\) 11.63 & 26.83 \(\pm\) 6.6 & 51.12 \(\pm\) 22.88 & 0.712 \\
13 & \(\beta\)-Germacene & 6.22 \(\pm\) 4.88 & 7.24 \(\pm\) 2.67 & 2.92 \(\pm\) 0.83 & 5.12 \(\pm\) 2.25 & 0.174 \\
14 & \(\beta\)-Panasingene & 3.45 \(\pm\) 3.22 & 2.77 \(\pm\) 0.55 & 1.46 \(\pm\) 0.4 & 2.85 \(\pm\) 1.06 & 0.402 \\
15 & \(\beta\)-Cadinene & 5.94 \(\pm\) 4.84 & 5.44 \(\pm\) 1.18 & 2.65 \(\pm\) 0.75 & 5.7 \(\pm\) 2.66 & 0.613 \\ \hline \hline \end{tabular} Note: The mean difference is significant with a 95% confident interval. \({}^{\circ}\) Data expressed as means and standard deviations of peak area; b comparison of high, medium and low concentrations and the toothpick method.  
\end{table} 
Table 5: Quantities of 15 selected common MVOCs of fungi culture inoculated with four different spore concentrations. 30 \({}^{\circ}\)C. The TIC chromatograms obtained from analyzing the MVOCs emitted by _A. flavus_ 5-3B grown at different temperatures were compared to select the preferred temperature (Figure 4). The fungi grown at 15 and 30 \({}^{\circ}\)C produced more amounts of sesquiterpenes compared to the fungi grown at 37 and 45 \({}^{\circ}\)C (Figure 4B). The morphologies of the fungi grown in 15, 30 and 37 \({}^{\circ}\)C are similar after seven days; however, the fungi grows slowly at 45 \({}^{\circ}\)C. The compound 1-butanol can be used as the indicator of fungi growth condition, because 1-butanol is produced largely from MEA medium. The presence of a large amount of 1-butanol (Figure 4A) in the fungi culture indicated the slow growth rate of fungi at 45 \({}^{\circ}\)C.  
[PERSON] _et al._ [62] reported that the optimum temperature for aflatoxin production occurred at 24 \({}^{\circ}\)C, and the maximal growth of _A. flavus_ isolates occurred at 29 and 35 \({}^{\circ}\)C. However, the optimum growth and aflatoxin production temperature may vary when growing on the different substrates. [PERSON] and [PERSON] [63] reported that the mycelial growth and sporulation of _A.