## 3 Results and Discussion
### Volatile Compounds of Cold Brew Samples
#### 3.3.17 [PERSON] et al. [38], in their study, reported that important compounds modified and formed during the dark roast defect, include indole, which is made from the wax surrounding coffee. The highest final roasting temperature should show the highest concentration of indole in the extracts. It is an unpleasant smelling animatic, cheesy compound that can also be formed during the roasting of serotonin and which behaves in the same way as the related tryptophan [30]. The mean indole content in cold brew coffee samples was 4.1 ug/g. The analyses carried out in the present cold brew experiment showed that almost all concentrations of this compound were from coffees B and were 85.1%, generally. The highest measured concentration was 33.5 ug/g. Due to the elevated abundance in the light roast defect samples, indole is also proposed as a chemical marker for the light roast defect [38]. There is no other similar research on cold brew coffee analysisto compare with. Otherwise, indole concentration in the unprocessed cocoa was below the odor threshold value of 51 ug/kg. In the processed samples, the amounts increased continuously with increasing roasting temperature. It was the most odor active among the four off-flavor compounds at 140 \({}^{\circ}\)C [83]. Moreover, indole low concentration is normally observed in commercial wines (1 mg/L to 10 mg/L, approximate mean 5 mg/L) [84].  
Additional parameters from the chromatography analysis for all volatile compounds are given in Table 5.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Nr** & **tR (min)** & **Compound** & **RI Exp. 1** & **RI Lit. 2** & **Identification 3** \\ \hline
1 & 4.17 & Pyrazine & 739 & 736 & RI, MS, IS \\ \hline
2 & 4.42 & Pyridine & 744 & 746 & RI, MS, IS \\ \hline
3 & 5.97 & 3(2H)-Furanone, dihydro-2-methyl- & 799 & 809 & RI, MS \\ \hline
4 & 6.24 & 4-Methylthiazole & 817 & 823 & RI, MS \\ \hline
5 & 6.42 & 2-Methylpyrazine & 835 & 831 & RI, MS \\ \hline
6 & 6.74 & Furfural & 835 & 833 & RI, MS, IS \\ \hline
7 & 7.87 & \(\alpha\)-Furfurylalcohol & 872 & 860 & RI, MS, IS \\ \hline
8 & 9.17 & Pyrazine, 2,6-dimethyl- and Pyrazine, 2,5-dimethyl- & 909 & 917 & RI, MS, IS \\ \hline
9 & 9.27 & Pyrazine, ethyl- & 926 & 921 & RI, MS \\ \hline
10 & 9.39 & Pyrazine, 2,3-dimethyl- & 926 & 926 & RI, MS \\ \hline
11 & 9.90 & \(\alpha\)-Pinene & 939 & 937 & RI, MS, IS \\ \hline
12 & 10.77 & Benzaldehyde & 970 & 962 & RI, MS, IS \\ \hline
13 & 10.87 & 2-Furancarboxaldehyde, 5-methyl- & 970 & 965 & RI, MS \\ \hline
14 & 11.29 & \(\beta\)-Pinene & 980 & 979 & RI, MS, IS \\ \hline
15 & 11.43 & 1-Octen-3-ol & 985 & 980 & RI, MS, IS \\ \hline
16 & 11.66 & 5-Hepten-2-one, 6-methyl- & 991 & 986 & RI, MS, IS \\ \hline
17 & 11.78 & 2-Octanone & 994 & 990 & RI, MS, IS \\ \hline
18 & 11.91 & 2-Furammethanol, acetate & 997 & 995 & RI, MS \\ \hline
19 & 11.97 & Pyrazine, 2-ethyl-6-methyl- & 1001 & 1003 & RI, MS \\ \hline
20 & 12.05 & Pyrazine, 2-ethyl-3-methyl- & 1003 & 1004 & RI, MS \\ \hline
21 & 12.11 & Pyrazine, 2-ethyl-5-methyl- & 1004 & 1005 & RI, MS, IS \\ \hline
22 & 12.84 & p-Cymene & 1030 & 1025 & RI, MS, IS \\ \hline
23 & 13.05 & Eucalypt & 1035 & 1032 & RI, MS, IS \\ \hline
24 & 14.44 & 2-Acetyl-1-methylpyrrole & 1083 & 1096 & RI, MS \\ \hline
25 & 14.55 & Pyrazine, 3-ethyl-2,5-dimethyl- & 1083 & 1082 & RI, MS \\ \hline
26 & 14.74 & Pyrazine, 2-ethyl-3,5-dimethyl- & 1088 & 1084 & RI, MS, IS \\ \hline
27 & 14.85 & Fenchone & 1091 & 1096 & RI, MS, IS \\ \hline
28 & 15.22 & Linalool & 1099 & 1099 & RI, MS, IS \\ \hline \hline \end{tabular}
\end{table}
Table 5: List of aromatic compounds based on retention time and analyzed methods.