## 3 Results and Discussion
Another study conducted on traditional pastrrma types found that the use of MTGase was effective on a few volatile compounds [16]. A correlation heat map was used to study the relationship between using MTGase and volatile compounds is shown in Figure 1. Although the use of different rates of MTGase did not lead to a statistically significant difference in the volatile compound profile of pastrrma, the correlation analysis showed that there was a difference between the groups. The use of different amounts of MTGase resulted in the formation of two clusters. The groups containing 0% (control) and 0.25% MTGase and the groups containing 0.5% and 1% MTGase were in the same clusters and showed closer correlations. It was also observed that the use of MTGase caused differences in the volatile compounds (Figure 1). Hexanal, one of the secondary products produced during the oxidation of linoleic acid and linoleic acid that has a characteristic odor of green grass [34], had a higher abundance in the 0.5% and 1% MTGase groups compared with the other groups. The free amino acid composition of pastrrma containing transglutaminase enzyme at different levels is presented in Table 5. Alanine, arginine, cystine, glutamic acid and valine were determined to be the dominant free amino acids. The effect of the enzyme treatment on cystine and phenylalanine was determined at the \(p<\) 0.01 level, and on arginine and proline at the \(p<\) 0.05 level. The lowest amounts of proline and arginine in the pastrrma samples were determined in pastrrma containing 0.25% enzyme. In terms of cystine, the lowest mean value was given by the control group, but the mean value of the pastrrma containing 0.25% enzyme did not vary from the mean value of the control group. It was observed that the mean phenylalanine content of the control group and pastrrma produced using 0.25% enzyme were higher than those of other groups (samples containing 0.50% and 1% enzyme) (Table 5). On the other hand, [PERSON] et al. [16] reported that MTGase \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Transglutaminase (\%)**} & \multicolumn{2}{c}{**Cutting**} & \multicolumn{2}{c}{**Stress–Relaxation**} \\ \cline{2-5}  & **Max. Cutting Force (N)** & **Max. Force (N)** & **Relaxation Time (s)** & **Min. Force (N)** \\ \hline Control & 18.71 b & 82.25 c & 80.42 & 25.54 \\
0.25 & 22.91 a & 100.74 b & 80.65 & 33.73 \\
0.50 & 22.20 a & 132.02 a & 109.79 & 37.76 \\
1 & 24.61 a & 118.04 a & 85.47 & 34.45 \\ \(p\) & 0.011 & \textless{}0.001 & 0.120 & 0.075 \\ SEM & 0.690 & 9.903 & 5.565 & 2.744 \\ \hline \hline \end{tabular}  
*a\({}^{<}\): Different letters indicate statistical difference in each column (\(p<\) 0.05). SEM: Standard error of mean.  
\end{table} 
Table 3: Effect of transglutaminase application on cutting and stress–relaxation properties. application (0.50%) in different pastrma type productions increased the level of histidine, alanine and proline. Additionally in the same study, the presence of MTGase decreased the levels of arginine, isoleucine, threonine and valine. These differences can be clarified by fiber type, the production conditions (traditional or industrial) of pastrma and the anatomical location of the muscle(s). The taste of the product is directly affected by the free amino acids and peptides formed as a result of proteolysis. Free amino acids are the precursor of some volatile compounds and therefore affect the aroma of dry-cured meat products. The degree of proteolysis in this type of meat product varies according to the raw material, process conditions (temperature, time, pH, a\({}_{\text{w}}\) and redox potential) and curing components (salt, nitrate nitrite and ascorbic acid) [35]. In addition, endogenous muscle enzymes cause the degradation of proteins [36].