## 3 Results and Discussion
### Volatile Compound Analysis  
The results of the analysis of volatile compounds were reported in Table 3. In general, volatile compounds belonging to aldehyde, ketone and alcohol chemical classes discriminated the geographical origin of EC samples, especially for light and medium roasting conditions. However, the development of furrans and sulfur compounds was pronounced in dark roasting EC samples [27; 28], reducing the differences attributable to the geographical origin. N-heterocyclic compounds, e.g., pyrroles, increase as the degree of roasting increases (D treatment), while pyrazines decrease [29].  
In order to summarize the results and reduce the dataset dimensionality [30], PCA was conducted. Figure 3 shows the biplot of the PCA, carried out on the chemical classes quantified in the EC samples. As previously stated, the dark roasting treatment caused a higher abundance of volatile compounds, in agreement with the work of [PERSON] et al. [31] and [PERSON] et al. [32]. In particular, a greater quantity of furan, ester, N-heterocyclic and sulfur compounds were present in the dark-treated samples. Moreover, the dark roasting of coffee beans reduced differences in VOCs by variety and provenance, corroborating the results obtained in the LDA. Esters were more abundant in the coffee Arabica varieties, as previously found by [PERSON] et al. [33]. Alcohols, ketones and aldehydes, as well as pyrazines, phenols and pyrimidines, were distributed between the light and medium treatments. Furthermore, the Arabica coffee samples had a higher quantity of phenols, contributing to spicy and smoky odors [33]. The roasted light and medium Robust varieties, i.e., INDIA Cherry and VIETNAM, showed higher amounts of pyrazines and pyrimidines, while aldehydes, alcohols and ketones were generally more abundant in the Arabica variety samples. These results confirm the findings of [PERSON] et al. [14], who reported higher amounts of alcohols in Arabica green coffee varieties. Furthermore, [PERSON] et al. [34] reported a higher quantity of sulfur compounds in coffee with 80% of Robust variety, while aldehydes, ketones and alcohols were present in higher quantities in samples with 80 % of Arabica variety.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **D\_BRAZIL** & \begin{tabular}{c} **D\_INDIA** \\ _Cherry_ \\ \end{tabular} & \begin{tabular}{c} **D\_COLOMBIA** \\ \end{tabular} & \begin{tabular}{c} **D\_PERU** \\ \end{tabular} & \begin{tabular}{c} **D\_UCANDA** \\ \end{tabular} & \begin{tabular}{c} **D\_VIETNAM** \\ \end{tabular} & \begin{tabular}{c} **Total** \\ \end{tabular} & \
\begin{tabular}{c} **Correct** \\ **Response (\%)** \\ \end{tabular} \\ \hline D\_BRAZIL** & 9 & 0 & 0 & 0 & 0 & 0 & 9 & 100.00 \\ D\_INDIA _Cherry_ & 0 & 7 & 0 & 0 & 0 & 2 & 9 & 77.78 \\ D\_COLOMBIA & 0 & 0 & 9 & 0 & 0 & 9 & 100.00 \\ D\_PERU & 0 & 0 & 0 & 9 & 0 & 9 & 100.00 \\ D\_USAD & 0 & 0 & 0 & 0 & 9 & 0 & 9 & 100.00 \\ D\_VIETNAM & 0 & 2 & 0 & 0 & 0 & 7 & 9 & 77.78 \\ \hline \multirow{2}{*}{M\_BRAZIL} & M\_INDIA & M\_COLOMBIA & M\_PERU & M\_USADDA & M\_VIETNAM & \\ \cline{2-7}  & M\_BRAZIL &
\begin{tabular}{c} **\_C\_\  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & \multicolumn{6}{c}{**Peak Area (\(\times\)10\({}^{6}\)) 1**} \\ \cline{2-7}  & & \multicolumn{6}{c}{**Robusta**} & \multicolumn{6}{c}{**Arabica**} \\ \hline
**Chemical Classes** & **RD 2** & **INDIA Cherry** & **VETNAM** & **UGANDA** & **FENU** & **COLOMBIA** & **BRAZIL** \\ \hline \multirow{3}{*}{Acids} & L & 0.512 \(\pm\) 0.107 pA & 0.458 \(\pm\) 0.112 b & 0.474