## 3 Results
### HS-SPME GC-MS Analysis of Volatile Organic Compounds
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Peak No.** & **Compound Name** & **Group** & \multicolumn{2}{c}{**Odor**} & \multicolumn{5}{c}{**Samples**} \\ \cline{3-10}  & & & **Characteristic** & **C1** & **C2** & **C3** & **C4** & **C5** & **C6** \\ \hline
1 & 2-Butanone & Ketones & Ethereal & 6.2 & 12.5 & 8.9 & 6.7 & 11.2 & 9.3 \\ \hline
2 & Furan & Furans & Ethereal & 5.8 & 10.9 & 10.1 & 9.3 & 13.7 & 10.9 \\ \hline
3 & 2-Oxopropanol & Aldehydes & Caramelly & 0.4 & 0.3 & 1.5 & 0.5 & 0.9 & 0.5 \\ \hline
4 & 2-Butanol & Alcohol & Fruity & 0.2 & 0.1 & 0.3 & 1.3 & 1.5 & 1.9 \\ \hline
5 & 2-Methylfuran & Furans & Chocolatey & 9.3 & 15.2 & 22.8 & 13.8 & 16.8 & 13.7 \\ \hline
6 & 2-Methylbutanal & Aldehydes & Chocolatey & 0.5 & 0.4 & 1.4 & 1.2 & 1.2 & 0.8 \\ \hline
7 & Methyl formate & Esters & Fruity & 6.7 & 5.8 & 5.2 & 5.8 & 4.2 & 1.3 \\ \hline
8 & 2,3-Butanedione & Ketones & Buttery & 0.5 & 0.4 & 3.6 & 1.1 & 1.2 & 0.6 \\ \hline
9 & 2-Methyl-3-buten-2-ol & Alcohol & Herby & 0.7 & 0.9 & 4.2 & 6.4 & 4.1 & 6.4 \\ \hline
10 & 3-Pentanone & Ketones & Ethereal & 0.4 & 0.4 & 0.5 & 0 & 1.2 & 1.1 \\ \hline
11 & 2,3-Pentanedione & Ketones & Buttery & 9.1 & 11.2 & 8.8 & 5.7 & 10.8 & 10.3 \\ \hline
12 & Hexanal & Aldehydes & Green & 0.6 & 0.7 & 0.5 & 0.2 & 0 & 0.5 \\ \hline
13 & 2-Methyl-2-butenal & Aldehydes & Green & 0.2 & 0.2 & 0.2 & 0.2 & 0.2 & 0.2 \\ \hline
14 & 3-Penten-2-one & Ketones & Fruity & 0.3 & 0.3 & 0.2 & 0.3 & 0.3 & 0.4 \\ \hline
15 & 3,4-Hexanedione & Ketones & Buttery & 0.3 & 0.3 & 0.3 & 0.5 & 0.3 & 0.4 \\ \hline
16 & 2-Methyl-1-butanol & Alcohol & Roasted & 0.3 & 0.3 & 0.2 & 0.2 & 0.3 & 0.4 \\ \hline
17 & Furfuryl methyl ether & Furans & Coffee & 0.4 & 0.4 & 0.1 & 0.2 & 0.7 & 0.5 \\ \hline
18 & Trimethyloxazole & Oxazoles & Nutty & 0.5 & 0.4 & 0.1 & 0 & 0 & 0.4 \\ \hline
19 & Methylpyrazine & Pyrazines & Nutty & 6.3 & 6.1 & 1.3 & 4.2 & 1.5 & 0.7 \\ \hline
20 & 3-Hydroxybutanone & Ketones & Buttery & 2.6 & 0 & 0.4 & 0 & 0.8 & 3.1 \\ \hline
21 & 1-Hydroxy-2-propanone & Ketones & Caramelly & 0.4 & 0.3 & 0.5 & 9.7 & 1.6 & 0.5 \\ \hline
22 & 3-Methyl-2-buten-1-ol & Alcohol & Fruity & 0.6 & 0.5 & 0.2 & 0.1 & 0.2 & 0.8 \\ \hline
23 & Acetic acid & Carboxylic acid & Acidic & 5.8 & 7.3 & 2.4 & 2.9 & 3.5 & 3.3 \\ \hline
24 & Furfural & Furans & Bready & 7.7 & 10.3 & 19.6 & 11.8 & 15.5 & 4.7 \\ \hline
25 & 1-Ethyl-2-pyrrolecalablehyde & Pyrroles & Roasted & 0.4 & 0.5 & 0.1 & 3.2 & 2.1 & 0.1 \\ \hline
26 & 2-Acetylfuran & Furans & Balsamic & 0.2 & 0.3 & 0.1 & 0.1 & 0.1 & 0.2 \\ \hline
27 & Furfuryl ether & Furans & Coffee & 0.5 & 0.5 & 0.3 & 0.2 & 0.2 & 0.2 \\ \hline
28 & 5-Ethyl-2.3-dimethylpyrazine & Pyrazines & Burnt & 0.4 & 0.5 & 0.6 & 0.3 & 1.6 & 0.6 \\ \hline
29 & Furfuryl propionate & Furans & Fruity & 0.2 & 0 & 0 & 3.3 & 1.3 & 0.2 \\ \hline
30 & Furfuryl acetate & Furans & Fruity & 2.3 & 1.1 & 0.4 & 0.1 & 0.5 & 1.3 \\ \hline
31 & 2-Ethyl-2-3-dimethylpyrazine & Pyrazines & Nutty & 2.7 & 0.2 & 0 & 0 & 0 & 1.6 \\ \hline
32 & 5-Methyl furfural & Furans & Caramelly & 8.4 & 1.9 & 0.7 & 2.4 & 0.6 & 5.8 \\ \hline
33 & 2-Furanmethanol & Furans & Bready & 11.6 & 3.4 & 1.2 & 3.1 & 1.2 & 9.6 \\ \hline
34 & Benzaldehyde & Aldehydes & Fruity & 2.6 & 1.6 & 0.5 & 3.7 & 0.3 & 3.7 \\ \hline
35 & Guaiacol & Phenolic compounds & Phenolic & 0.5 & 0 & 0 & 0.2 & 0 & 0.6 \\ \hline
36 & \(\gamma\)-Butyrolactone & Furans & Creamy & 2.6 & 1.5 & 0.3 & 0.2 & 0.2 & 1.8 \\ \hline
37 & 2-Acetyl-5-methylfuran & Furans & Nutty & 0.4 & 2.8 & 1.5 & 0 & 0 & 0.5 \\ \hline
38 & 2-Formyl-1-methylpyrrole & Pyrroles & Roasted & 0.9 & 0.4 & 0.1 & 0.5 & 0.1 & 0.7 \\ \hline
39 & 5-Methyl–cyclopentapyrazine & Pyrazines & Earthy & 0.5 & 0.1 & 0.9 & 0.6 & 0.1 & 0.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Volatile organic compound contents (%) identified by HS-SPME GC-MS.  
Figure 3: Total ion chromatograms of volatile organic compounds identified in coffee samples by HS-SPME-GC-MS analysis: (**a**) C1; (**b**) C2; (**c**) C3; (**d**) C4; (**e**) C5; and (**f**) C6.