## 3 Results
### Volatile Compounds  
Altering FAs' composition in meat directly affects the VCs formed during cooking [20]. Particularly, the autoxidation of FAs correlates with the formation of aldehydes, furans, and organic acids such as hexanoic acid [21]. Among the VCs, furan and pyrazine are particularly important contributors to enhancing the flavor of beef [22]. A total of 24 VCs were identified and classified according to their chemical nature (Table 4: 11 aldehydes, 5 alcohols, 1 ketone, 1 furan, and 6 aliphatic hydrocarbons. Hexanal was the predominant aldehyde, followed by pentanal and heptanal. Other aldehydes, such as nonanal, octanal, and benzaldehyde, were found to be less prevalent than other aldehydes. Aldehydes are the dominant chemical group detected in cooked meat samples of ruminants. In addition, aldehydes are known to be mostly derived from PUFA oxidation during heat treatment and amino acids' degradation during the Maillard reaction through Strecker degradation [23]. Octane-2-3-dione was the main ketone in both samples. [PERSON] [24] reported that octane-2-3-dione is formed in the Maillard reaction of lysine and ribose during prolonged heating, which supports our findings. Furan derivatives are typical compounds formed in the Maillard reaction and fat degradation [22]. In both samples, only a single furan was identified. Among the analyzed VCs, 14 components showed significant differences between samples. Therefore, principal component analysis (PCA) was performed to determine the relationship between the VCs in steaks (Figure 1). The two principal components accounted for 92.2% and 7.76%, respectively (99.96% in total). Aldehydes, such as hexanal, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Volatile Compounds** & **Seared Steak** & **Reverse-Seared Steak** & **t** \\ \hline _aldehydes_ & & & \\ hexanal & 16.64 \(\pm\) 0.45 a  & 5.13 \(\pm\) 0.01 b  & 44.30 *** \\ octanal & 3.25 \(\pm\) 0.19 a  & 2.73 \(\pm\) 0.97 b  & 4.07 * \\ nonanal & 6.44 \(\pm\) 0.11 & 6.41 \(\pm\) 0.20 & 0.26 \\ (E)-2-nonenal & 1.45 \(\pm\) 0.06 & 1.55 \(\pm\) 0.10 & \(-\)1.37 \\ decanal & 0.32 \(\pm\) 0.02 & 0.39 \(\pm\) 0.13 & \(-\)0.87 \\ (E)-2-decenal & 3.83 \(\pm\) 0.32 a  & 2.47 \(\pm\) 0.04 b  & 45.62 *** \\ benzaldehyde & 0.81 \(\pm\) 0.12 a  & 1.61 \(\pm\) 0.05 b  & \(-\)10.76 *** \\ tridecanal & 0.36 \(\pm\) 0.20 & 0.38 \(\pm\) 0.05 & \(-\)0.69 \\ tetradecanal & 0.96 \(\pm\) 0.15 & 0.89 \(\pm\) 0.10 & 1.31 \\ pentadecanal & 2.08 \(\pm\) 0.15 a  & 1.62 \(\pm\) 0.46 b  & 16.38 *** \\ hexadecanal & 2.73 \(\pm\) 0.23 a  & 3.45 \(\pm\) 0.95 b  & \(-\)12.75 *** \\ \hline _ketones_ & & & \\ octane-2-3-dione & 0.32 \(\pm\) 0.15 a  & 0.53 \(\pm\) 0.75 b  & \(-\)4.60 * \\ _alcohols_ & & & \\
1-hexanol & 3.06 \(\pm\) 0.65 a  & 1.08 \(\pm\) 0.04 b  & 46.03 *** \\ heptanal & 2.44 \(\pm\) 0.26 a  & 1.45 \(\pm\) 0.08 b  & 19.56 *** \\
1-heptanol & 0.87 \(\pm\) 0.12 & 0.75 \(\pm\) 0.03 & 1.69 \\
1-octen-3-ol & 1.12 \(\pm\) 0.31 & 1.11 \(\pm\) 0.04 & 0.24 \\
1-octanol & 1.65 \(\pm\) 0.25 a  & 1.41 \(\pm\) 0.06 b  & 6.30 ** \\ \hline _furans_ & & & \\
2-pentylfuran & 1.13 \(\pm\) 0.21 a  & 0.57 \(\pm\) 0.03 b  & 4.64 * \\ \hline _aliphatic hydrocarbons_ & & & \\ dodecane & 0.19 \(\pm\) 0.17 & 0.19 \(\pm\) 0.02 & 0.25 \\ tridecane & 0.49 \(\pm\) 0.31 & 0.37 \(\pm\) 0.16 & 1.33 \\ tetradecane & 1.02 \(\pm\) 0.01 a  & 0.60 \(\pm\) 0.05 b  & 14.29 *** \\ hexadecane & 0.31 \(\pm\) 0.03 a  & 0.30 \(\pm\) 0.13 b  & 0.13 * \\ heptadecane & 0.12 \(\pm\) 0.15 & 0.19 \(\pm\) 0.05 & \(-\)2.21 \\ octadecane & 0.08 \(\pm\) 0.00 a  & 0.15 \(\pm\) 0.02 b  & \(-\)5.55 ** \\ \hline \hline \end{tabular} Values are presented as mean \(\pm\) SD (\(n=3\)); *, **, *** indicate significant differences as \(p<0.05\), \(p<0.01\), and \(p<0.001\), respectively; different letters indicate significant differences (\(p<0.05\)).  
\end{table} 
Table 4: Volatile compounds (%) of seared and reverse-seared steaks.