# Headspace Solid-Phase Microextraction Analysis of Volatile Components in Peanut Oil
## 2 Results and Discussion
### Differences in Volatile Components of Peanut oil Prepared at Different Roasting Temperatures  
The composition of volatiles in the oil samples was different, and a total of 66 volatile components were identified (Table 1). The results show that the primary components of peanut oil at the roasting temperature of 120 \({}^{\circ}\)C were hexanal, nonanal, methyl pyrrol-2-yl ketone, \(p\)-ethylphenol, 2-methylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-3-methylpyrazine, and 2-ethyl-3,6-dimethylpyrazine. When the roasting temperature was 140 \({}^{\circ}\)C, the primary components of peanut oil were hexanal, dodecane, undecane, methyl pyrrol-2-yl ketone, 2-methoxy-4-vinylphenol, 2, 5-dimethylpyrazine, 2-dimethylpyrazine, and 2-ethyl-3,6-dimethylpyrazine. The primary components of peanut oil at the roasting temperature of 160 \({}^{\circ}\)C were (\(E\))-2-heptenal, nonanal, \(p\)-vinylphenol, 2-methylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-3-methylpyrazine, and 2-ethyl-3,5-dimethylpyrazine. Figure 3: Comparison of the contents of the total volatiles in Hekei-140 at different absorption times using HS-SPME. The data correspond to the mean \(\pm\) SD of triplicate experiments. \({}^{\text{a-c}}\): Values possessing different superscripts are significantly different (\(p<0.05\)). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{Compound\({}^{*}\)} & \multicolumn{1}{c}{R1\({}^{*}\)} & \multicolumn{1}{c}{Relative Content (\(\Sigma_{3}\))\({}^{*}\)} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\ \cline{2-10} \multicolumn{1}{c}{} & No-120\({}^{*}\) & No-140\({}^{*}\) & No-160\({}^{*}\) & No-190\({}^{*}\) & Heke-120\({}^{*}\) & Heke-120\({}^{*}\) & Heke-120\({}^{*}\) & Heke-140\({}^{*}\) \\ \hline Allidays & 775 & 6.64 \(\pm\) 1.17 & 1.74 \(\pm\) 0.04 & 2.21 \(\pm\) 0.28 & 3.33 \(\pm\) 0.15 & 4.88 \(\pm\) 0.35 & 2.36 \(\pm\) 0.21 & 2.01 \(\pm\) 0.23 \\ Empirical & 726 & 10.74 \(\pm\) 0.12 & 2.01 \(\pm\) 0.15 & 2.67 \(\pm\) 0.14 & 1.89 \(\pm\) 0.02 & & 1.89 \(\pm\) 0.02 \\ Empirical & 726 & 3.52 \(\pm\) 0.45 & 2.01 \(\pm\) 0.15 & 2.67 \(\pm\) 0.14 & 4.41 \(\pm\) 0.15 & & 1.82 \(\pm\) 0.18 \\ In  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{Compound} & RI & \multicolumn{6}{c}{Relative Content (\(\
abla\))} \\ \cline{2-9}  & No-123 & No-140 & No-140 & No-140 & Hads-123 & Hads-140 & Hems-123 & Hems-140 \\ \hline \(\Delta\)Multiplicative & 70\(\pm\) 48 & 3.72 \(\pm\) 48 & 5.93 \(\pm\) 0.13 & 3.50 \(\pm\) 0.12 & 5.64 \(\pm\) 0.56 & 5.68 \(\pm\) 0.27 & 3.66 \(\pm\) 0.19 \\ \(\Delta\)2.5 DD/Lyapunov & 881 & 9.82 \(\pm\) 126 & 11.40 \(\pm\) 0.15 & 12.96 \(\pm\) 1.54 & 16.80 \(\pm\) 0.82 & 14.65 \(\pm\) 0.67 & 21.36 \(\pm\) 0.98 & 13.54 \(\pm\) 1.79 \\ \(\Delta\)V  
The aldehydes produced by the oxidation of fatty acids included hexanal, nonanal, (_E_)-2-heptenal, 2-octenal, (_E_)-2-nonenal, (_E_)-2-decenal, (_2E,4Z_)-decadienal, (_2E,4E_)-decadienal, and benzaldehyde [24]. According to previous studies, the pyrazines present in peanut oil are the source of roasting flavor [25], and pyrazines are the products of the Mener reaction that occur in meat, fish, cocoa, nuts, popcorn, and bread [26]. From the data presented in Figure 4, it can be observed that the primary components of Tainan S. No. 9 peanut oil were pyrazines, and their content was increased greatly at high temperatures (160 \({}^{\circ}\)C). Such compounds are the products of the Maillard reaction, which increases their content upon an increase in the processing temperature. Two compounds related to the roasting taste were produced, including 2,5-dimethylpyrazine and 2-ethyl-3,5-dimethylpyrazine. These pyrazines are considered to be the key factors that cause peanut oil to possess a strong nutty flavor [11]. The content of aldehydes in Tainan S. No.