## 3 Results and Discussion
### Volatile Profile
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{N\({}^{*}\)}} & \multirow{2}{*}{**Compound**} & \multicolumn{2}{c}{**Unknown**} & \multicolumn{2}{c}{**Reference**} & \multicolumn{3}{c}{**Raw Meet Alternatives (EMA)**} & \multicolumn{3}{c}{**Gilled Meet Alternatives (CMA)**} & \multicolumn{3}{c}{**2-Way ANOVA**} \\  & & **LR1\({}^{*}\)** & **LR1\({}^{*}\)** & **RMA** & **RMA** + 0.5\%** & **RMA** + 1.0\%** & **RMA** & **CMA** & **CMA** + 0.5\%** & **RMA** + 1.0\%** & **RMA** + 0.5\%** & **RMA** + 1.0\%** & **RMA** + 0.5\%** & **RMA** + 0.5\%** & **RMA** + 0.5\%** & **RMA** + 0.5\%** & **RMA** + 0.5\%** & **RMA** + 0.5\%** \\ \hline
35 & 2-Ethly-5 & 973 & 973 & 57.28 \(\pm\) 10.19 * & 41.63 \(\pm\) 7.28 * & 51.90 \(\pm\) 7.34 * & 647.55 \(\pm\) 134.84 * & 850.09 \(\pm\) 167.10 * & 1390.69 \(\pm\) 158.40 * & - & - & 0.000 \\
36 & 2-Ethly-5 & 1053 & 1053 & 89.18 \(\pm\) 11.76 * & 77.79 \(\pm\) 13.32 * & 79.78 \(\pm\) 2.08 * & 701.87 \(\pm\) 196.78 * & 853.54 \(\pm\) 179.08 * & 1392.55 \(\pm\) 198.91 * & - & - & 0.002 \\
37 & 2-Ethly-3 & Gehly-5 & 1132 & 1138 & 6.87 \(\pm\) 41.0* & n.d. * & 2.46 \(\pm\) 4.26* & 126.15 \(\pm\) 2.06 * & 151.17 \(\pm\) 27.13 * & 271.03 \(\pm\) 57.99 * & - & - & 0.002 \\
38 & **Ottawa** & **964.00 \(\pm\) 1326.6* & **S840.08 \(\pm\) 417.59* & **S719.21 \(\pm\) 224.49* & **893.64 \(\pm\) 28.79* & **866.31 \(\pm\) 132.82 * & **8847.88 \(\pm\) 89.96 * & - & - & **0.000** \\
38 & **Pyrable** & 727 & 731 & n.d. & n.d. & n.d. & 2.083 \(\pm\) 57.51 & 22.82 \(\pm\) 17.28 & 720.24 \(\pm\) 7.31 & NS & 0.000 & NS \\
39 & 2-Penlyraum & 978 & 994 & 800.61 \(\pm\) 1252.79 & 553.32 \(\pm\) 17.72 * & 5136.56 \(\pm\) 258.42 * & 7706.36 \(\pm\) 314.55 * & 763.53 \(\pm\) 394.20* & 7796.63 \(\pm\) 87.75* & - & - & 0.011 \\
40 & **Malot** & 1276 & 1272 & 49.38 \(\pm\) 88.24 & 494.76 \(\pm\) 342.44 & 582.65 \(\pm\) 118.56 & 99.60 \(\pm\) 229.24 & 103.15 \(\pm\) 22.85 & 1380.71 \(\pm\) 197.83 & 0.024 & 0.000 & NS \\
40 & **Total variables** & & & & & & & & & & & \\  & & & & & & & & & & & & & \\ \hline \multicolumn{1}{c}{\({}^{1}\) Linear retention index (LR1) based on 30 m HP-11 ms column. Reference values obtained by comparison with sources from the literature in the NIST Chemistry WebBook. ([[https://webweb.mit.gov/documents/](https://webweb.mit.gov/documents/)]([https://webweb.mit.gov/documents/](https://webweb.mit.gov/documents/))) accessed on 20 May 2022) using similar columns and similar temperature programs.} & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._All six pyrazine compounds identified in the analyzed samples have previously been reported in beef, pork, chicken and mutton [34]. Pyrazines are derived from Maillard reactions and their presence in meat matrices is mainly associated with roasted aromas [39; 40; 41]. Small amounts of pyrazines are initially present in RMA, and do not vary with Mb addition. They are likely formed during the extrusion-cooking process in the production of TSP. Temperatures at which soy protein are heated during extrusion generally range from 120 to 180 \({}^{\circ}\)C, at which point pyrazines can be formed via the Maillard reaction [42; 43; 44]. HS-SPME-GC-MS analysis of raw materials (data not shown) confirmed the presence of all six pyrazines in TSP, and similar findings have previously been reported in the literature [45]. Grilling is expected to increase the pyrazine content in plant-based meat alternatives considerably, but Mb supplementation in GMA is found to further stimulate pyrazine formation significantly (\(p<0.05\)). Interactions are known to occur between products derived from lipid-oxidation and intermediates of the Maillard reaction [46; 47]. The pyrazine fraction of the total volatile profile increases from 11.9 \(\pm\) 3.0% in GMA to 16.1 \(\pm\) 2.3% in GMA + 1.0%Mb. Other Maillard-related compounds, such as furfural and furfuryl alcohol [48], are found to exhibit similar patterns.