## 3 Results and Discussion
### VOCs of Green Coffee Beans
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**R.T. (Min)** & **CAS Number** & **Volatile Compounds** & & \multicolumn{2}{c}{**Quantities**} \\  & & **High** & **Medium** & **Low** \\ \hline
10.9 & 100-52-7 & Benzaldehyde & 0.00 ns & 0.68 & 0.80 \\
16.0 & 2548-87-0 & (E)-2-Octenal & 0.00 ns & 0.00 & 0.84 \\
18.9 & 124-19-6 & Nonanal & 7.46 a  & 7.07 a  & 4.17 b  \\
22.9 & 56114-69-3 & Benzaldehyde, 2,5-bis[(trimethylsilyl)oxy]-2.00 & 2.00 a  & 1.40 b  & 2.02 a  \\
22.6 & 18829-56-6 & (E)-2-Nonanal & 0.00 ns & 0.00 & 1.62 \\
26.6 & 5910-87-2 & (E,E)-2,4-Nonadien & 0.00 ns & 0.00 & 0.66 \\
40.7 & 121-33-5 & 4-Hydroxy-3-methoxybenzamidedehyde (Vanilene) & 2.49 a  & 2.78 a  & 0.65 b  \\
**Kettones** & & & & & \\
20.2 & 1000302-96-9 & Propenone, 1-(4-nitrophenyl)-3-phenylamino-3.17 ns & 0.00 & 0.00 \\
27.6 & 2758-18-1 & 3-Methyl-2-cyclopenten-1-one & 1.19 ns & 0.00 & 0.00 \\
45.4 & 105-86-2 & Geraniol & 1.23 b  & 1.71 a  & 0.81 c  \\
71.3 & 502-69-2 & 2-Pentadecanone, 6,10,14-trimethyl- & 0.73 c  & 4.26 b  & 5.07 a  \\
8.4 & 141-32-2 & 2-Propenoic acid, butyl ester & 0.44 ns  & 0.38 & 0.26  \\
22.2 & 103-09-3 & Acetic acid, 2-ethylhexyl ester & 2.02 a  & 1.59 b  & 0.32 c  \\
22.2 & 72218-58-7 & 3-Methylheptyl acetate & 0.84 ns  & 0.00 & 0.00 \\
26.1 & 109-15-9 & 2-Methyl-propanoic acid, octyl ester & 4.33 ns  & 0.00 & 0.00 \\
54.3 & 1000298-25-6 & 1,3-Dimethylbutyl isopropylphosphonofluiduidate & 0.66 ns  & 0.00 & 0.00 \\
74.2 & 628-97-7 & Hexadecanoic acid, ethyl ester & 1.41 a  & 1.43 a  & 0.88 b  \\
80.7 & 544-35-4 & Linoleic acid ethyl ester & 0.00 ns  & 0.53 & 0.59  \\  & & **Acids derivates** & & \\
6.9 & 503-74-2 & 3-Methyl-butanoic acid & 0.34 c  & 2.32 b  & 2.84 a  \\
6.7 & 4536-23-6 & 2-Methyl-hexanoic acid & 1.51 a  & 1.02 b  & 0.39 c  \\
7.2 & 116-53-0 & 2-Methyl-butanoic acid & 0.00 ns  & 0.00 & 1.80 \\
8.2 & 541-47-9 & 3-Methyl-2-butenoic acid & 1.34 a  & 0.69 b  & 0.38 c  \\  & & **Carbovilic acids** & & & \\
2.3 & 64-19-7 & Acetic acid & 0.12 c  & 1.02 b  & 1.32 a  \\
6.5 & 109-52-4 & Pentanoic acid & 0.00 & 0.59 b  & 1.80 a  \\
12.1 & 142-62-1 & Hexanoic acid & 0.00 ns  & 0.00 & 1.06 \\
12.1 & 107-92-6 & Butanoic acid & 0.00 ns  & 0.00 & 1.29  \\
24.9 & 124-07-2 & Octanoic acid & 0.83 c  & 1.99 b  & 5.72 a  \\
31.6 & 112-05-0 & Nonanoic acid & 2.43 c  & 3.42 b  & 4.80 a  \\  & & **Lactones** & & & \\
9.0 & 96-48-0 & \(\gamma\)-Butrylolactone & 0.00 ns  & 0.00 & 0.39  & **Aromatics** & & \\
12.0 & 108-95-2 & Phenol & 2.34 a  & 1.54 b  & 0.00 & 0.00 \\
14.2 & 5989-27-5 & (D-Limonene) & 1.98 a  & 2.01 a  & 1.36 b  \\
17.8 & 90-05-1 & 2-Methoxy-phenol (Guaiocl) & 0.66 ns  & 0.00 & 0.00 \\
34.2 & 7786-61-0 & 2-Methoxy-4-vinylphenol & 9.92 a  & 7.01 b  & 2.27 c  \\
37.2 & 584-84-9 & Benzene, 2,4-diisocyanato-1-methyl-75.1 & 2.48 a  & 1.79 b  & 0.00 & 0.84  \\
75.1 & 33777-9 The furan compounds significantly decreased in low-quality coffee, with 2-methylfuran and furan representing the most abundant compounds, increasing 2.5 times more than in high-quality coffee. In the literature, these compounds provide negative aromas (smoky or roasted) [28] and are linked to causing mutagenesis in mice [29]; therefore, the European Commission published a recommendation regarding monitoring the presence of this compound in foods [30]. Thus, in green coffee, this family is shown to decrease coffee quality. Pyridine (5.73%) and 2,5-di methyl-pyridine (4.01%) were found in much higher proportion in low-quality coffee in pyrazines and pyrimidines families, with significant results. These VOCs have roasted and burnt notes [21]. As for the group of pyrroles, the main volatile composition varied in the different samples. In medium- and high-quality coffee, 1H-pyrrole (1.12-1.13%) was the main VOC found, and it smells like dried fruit [31]. However, in low-quality coffee, 3,4-dihydro-2,2,3-trimethyl-2H-pyrrole 1-oxide (1.05%) and 1H-indole (0.26%) appeared in low proportion. These compounds are linked to a roasted odor [9].