## 3 Results and Discussion
### Volatile Compounds
\begin{tabular}{l c c c c c c c c c c} \hline \hline
**Factors** & \multicolumn{4}{c}{**Cooking Method (C)**} & \multicolumn{4}{c}{**Muscle (M)**} & \multicolumn{4}{c}{**C.M**} \\ \hline  & **Stewing** & **Roasting** & **SEM** & _p-v_ & **SM \({}^{\$}\)** & **BF** & **RF** & **SEM** & _p-v_ & _p-v_ \\ \hline _Strecker aldehydes_ & & & & & & & & & & \\
2-Methyl butanal & 15.9 & 15.9 & 1.42 & 0.988 & 16.3 & 18.2 & 13.2 & 1.42 & 0.355 & NS \\
3-Methyl butanal & 28.1 & 27.3 & 2.23 & 0.857 & 28.9 & 32.2 & 22.2 & 2.23 & 0.167 & NS \\ Benzaldehyde & 4.1 \({}^{\$}\)b & 2.0 \({}^{\$}\)a & 0.20 & \textless{}0.001 & 3.1 & 3.3 & 2.7 & 0.20 & 0.431 & \textless{}0.001 \\ \hline _Thiophenes_ & & & & & & & & & & \\
2-Methyl thiophene & 0.7 \({}^{\$}\)b & 0.3 \({}^{\$}\)a & 0.07 & \textless{}0.001 & 0.6 & 0.6 & 0.4 & 0.07 & 0.572 & \textless{}0.01 \\ \hline _Ketones_ & & & & & & & & & & \\
2-3-Butanedione & 35.6 & 35.5 & 4.42 & 0.991 & 36.8 & 40.8 & 29.3 & 4.42 & 0.563 & NS \\
2-Heptanone & 3.9 & 3.2 & 0.20 & 0.086 & 3.1 & 3.9 & 3.5 & 0.20 & 0.366 & NS \\
3-Heptanone & 1.4 & 1.6 & 0.12 & 0.623 & 1.6 & 1.6 & 1.3 & 0.12 & 0.569 & NS \\ \hline _Sulfides_ & & & & & & & & & & \\ Dimethyl disulfide & 4.6 \({}^{\$}\)b & 0.2 \({}^{\$}\)a & 0.41 & \textless{}0.001 & 2.7 & 2.5 & 2.0 & 0.41 & 0.786 & \textless{}0.001 \\ Dimethyl trisulfide & 27.3 \({}^{\$}\)b & 0.7 \({}^{\$}\)a & 2.42 & \textless{}0.001 & 15.9 & 14.0 & 12.2 & 2.42 & 0.839 & \textless{}0.001 \\ \hline _Furans_ & & & & & & & & & & \\
2-PentyI furan & 0.9 \({}^{\$}\)b & 0.1 \({}^{\$}\)a & 0.12 & \textless{}0.001 & 0.6 & 0.4 & 0.5 & 0.12 & 0.837 & \textless{}0.01 \\ \hline _Alcohols_ & & & & & & & & & & \\
1-Hexanol & 0.3 & 0.3 & 0.04 & 0.625 & 0.3 & 0.4 & 0.2 & 0.05 & 0.203 & NS \\
2-Ethyl hexanol & 0.0 & 0.4 & 0.15 & 0.176 & 0.3 & 0.4 & 0.0 & 0.15 & 0.615 & NS \\ \hline _Acids_ & & & & & & & & & & \\ Octanoic acid & 0.2 & 0.2 & 0.02 & 0.876 & 0.2 & 0.2 & 0.1 & 0.02 & 0.798 & NS \\ \hline \hline \end{tabular}   
Dimethyl disulphide (DMDS), dimethyl trisulphide (DMTS), 3- and 2-methylbutanal, 2-methylthiophene, and benzaldehyde were included as markers for different pathways of the Maillard reaction, a complex chemical reaction between amino acids and reducing  
Figure 2: (**a**) Volatile compound content (ng/g) in the muscles depending on the applied heat treatment for Benz—Benzaldehyde, DMDS—dimethyl disulphide, and DMTS—dimethyl trisulfide. (**b**) Volatile compound content (ng/g) in the muscles depending on the applied heat treatment for 2 Methioph—2-Methyl liiophene and 2 PeFur—2-Pentyl furan. $ SM—_Semimembranosus_; BF—_Biceps femoris_; RF—_Rectus femoris_.,a,b,c Values for one compound that do not share a common superscript are significantly different (\(p<0.05\)). sugars that occurs at high temperatures. 2-Methylthiophene may be formed from the Maillard reaction of giving 1,4-diketones, with further reactions with, for example, H2S from cysteine [38]. The compounds 3-methylbutanal and 2-methylbutanal are formed from the Strecker degradation of leucine and isoleucine [39]. Benzaldehyde may be formed by the same mechanism as the rare amino acid phenylglycine, but its abundance in meat suggests that there are alternative routes of formation. DMDS and DMTS are formed through the Strecker degradation of methionine to release methanethiol, followed by an oxidation reaction to form DMDS and DMTS. DMDS and DMTS were more than 20\(\times\) higher in the stewed meat, while the other products of Strecker degradation, such as the methyl butanal isomers, were unchanged. This may have been due to the presence of onions in the stewing mix giving rise to additional sulfur-containing precursors. Their formation has been shown to be inhibited by the presence of anti-oxidants or Maillard-produced thiols [40]. In wine, disulphide and trisulphide formation may be catalyzed by the presence of CuII and FeIII [41].