## 3 Results and Discussion
### Effect of Added Fingerroot Essential Oil on Formation of HAs  
The meatballs with added essential oil were fried at a temperature of approximately 190 \({}^{\circ}\)C. Figure 2A shows the results of the determination of the HAs. Only the concentration of MeIQx was significantly lower with the addition of 0.5 wt% EOF, with a reduction of 39%. The other compounds, PHIP, norharman, and harman, were significantly increased via the addition of EOF in increasing concentrations, with an increase of 59% for PhIP, 61% for norharman, and 118% for harman with the highest addition of EOF (2.5 wt%). The highest PhIP concentration of 0.64 ng/g was found with the addition of 0.5 wt% EOF. This PhIP concentration was significantly higher than all other PhIP concentrations when lower and higher amounts of EOF were added. An increase of 213% in the concentration of PhIP was observed compared with the control. However, the PhIP concentrations in all batches showed high standard deviations compared with the other HAs. One reason for the increase in most of the HA concentrations in this study may be the use of the EOF compared with the study by [PERSON] et al. [29], where fresh or dried roots were used in the beef patties. The authors found that pinocchrin and pinostrobin, which are found in fingerroot, had high antioxidant activity, using the DPPH assay to determine free radical scavenging activity. Phenolic compounds are not only antioxidants but are also effective in reducing the concentrations of HAs, as reported in different studies [30; 31; 32; 33; 44; 45]. Increases in the concentrations of \(\beta\)-carbolines were shown in earlier studies using different spices [22]. Increases in the levels of HAs, such as PhIP, in the presence of pro-oxidant substances have also been reported [46]. Increasing weight loss could also favor an increase in HA levels, as reported in [22; 46]. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Condition**} & \multirow{2}{*}{**Batch**} & \multirow{2}{*}{**Shelf-Life 1**} & \multicolumn{4}{c}{**Microbial Reduction (log cfu/g) 2**} \\ \cline{4-6}  & & & **TVC** & **LAB** & **Enterobacteriaceae** \\ \hline Addition & Control & 3 & & & \\  & 0.25 & 3 & 0.27 \(\pm\) 0.14 a & 0.15 \(\pm\) 0.06 a & 0.18 \(\pm\) 0.46 a \\  & 0.50 & 3 & 0.34 \(\pm\) 0.22 a & 0.27 \(\pm\) 0.12 a & 0.50 \(\pm\) 0.99 a \\  & 1.00 & 9 & 0.71 \(\pm\) 0.10 ab & 0.74 \(\pm\) 0.10 ab & 3.76 \(\pm\) 0.54 b \\  & 2.50 & 15 & 2.22 \(\pm\) 1.48 b & 2.71 \(\pm\) 1.84 b & 6.65 \(\pm\) 0.08 c \\ Marinated & Control & 3 & & & \\  & 0.25 & 9 & \(-\)0.57 \(\pm\) 0.56 a & 0.09 \(\pm\) 0.76 a & 4.85 \(\pm\) 1.05 b \\  & 0.50 & 9 & 0.27 \(\pm\) 0.66 a & \(-\)0.16 \(\pm\) 0.72 a & 6.89 \(\pm\) 0.51 c \\  & 1.00 & 12 & 1.08 \(\pm\) 0.48 ab & 0.13 \(\pm\) 0.59 a & 6.89 \(\pm\) 0.51 c \\  & 2.50 & 18 & 3.83 \(\pm\) 0.60 c & 2.97 \(\pm\) 0.38 c & 6.89 \(\pm\) 0.51 c \\ \hline \hline \end{tabular} 1
[FOOTNOTE:1]Footnote 1: footnotetext: Shelf-life based on TVC standard criterium. 2  
\end{table} 
Table 1: Shelf-lives and microbial reductions in TVC, LAB, and Enterobacteriaceaeae in minced meat with the addition of EOF. The correlation plot is shown in Figure 3. Strong negative correlations were found between the addition of EOF and the TVC (r = \(-\)0.91; \(p\) < 0.05) as well as the Enterobacteriaceaeeeee count after storage for 18 days (\(-\)0.99; \(p\) < 0.001), which indicated the strong antimicrobial activity of EOF. Significant positive correlations were observed between the addition of EOF and weight loss (\(p\) < 0.05) as well as the harman concentration in pan-fried meatballs (\(p\) < 0.01). In addition, a positive correlation was found between weight loss and harman levels (\(p\) < 0.05). However, a significant correlation does not necessarily indicate a causal relationship.