## 3 Results and Discussion
### Relationship between Coffee Acceptability and Volatile Compounds  
Volatile compounds in the coffee samples were investigated by PCA (Figure 1a,b). StarbucksCS, TwosomeplecSC, and Folgers samples were positioned in quadrants 1 or 4, and most volatile compounds were also placed close to CS and Folgers samples. The CB and CM samples were positioned close together by extraction method rather than coffee variety. ColombiaCB and KenyaCB were related to 3,5-ocatdion-2-one (V15), 5-methyl-2-furaldehyde (V7), furfural (V3), and tetradecanoic acid (V36). ColombiaCM and KenyaCM were not related to any particular volatile compounds. This suggests that different extractions could influence volatile compound profiles markedly. However, blended coffees, BlendingCB and CM, were placed close to each other, showing that they were not different regardless of the extraction method. RTD samples were arranged in quadrant 3, and only BaristaRTD samples were slightly related to 3-methylphenol (V13) and nonanal (V22). The overall result of the confidence ellipse explained that sample discrimination by the brewing method was in the Colombia and Kenya samples. Furthermore, CS samples and Folgers samples were clearly discriminated between Colombia, Kenya, and RTD samples by volatile compounds.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{\(p\)-Value} \\ \cline{2-4}  & **Variety (Brand) 1** & **Brewing Method 2** & **Variety \(\times\) Brewing Method** \\ \hline Overall Liking & \(<\)0.0001 & 0.0149 & 0.0071 \\ Bitterness Intensity & \(<\)0.0001 & \(<\)0.0001 & 0.0202 \\ CoffeeID Intensity & 0.0041 & 0.1240 & 0.0073 \\ \hline \hline \end{tabular}
\end{table}
Table 7: \(p\)-Values of coffee variety (brand) and brewing method effects for consumers’ overall liking, bitterness intensity, and coffeeID intensity of CB and CM samples.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Sample Name 1**} & \begin{tabular}{c} **Overall** \\ **Liking 2** \\ \end{tabular} & \
\begin{tabular}{c} **Bitterness** \\ **Intensity 2** \\ \end{tabular} &
\begin{tabular}{c} **CoffeeID** \\ **Intensity 2** \\ \end{tabular} \\ \hline BlendingCB & \(4.29\pm 1.97\) b,c,d & \(4.89\pm 1.75\) d & \(5.63\pm 1.53\) b,c,d \\ BlendingCM & \(4.56\pm 2.00\) b,c,d & \(4.89\pm 1.78\) d & \(5.21\pm 1.37\) e,f \\ ColombiaCB & \(3.64\pm 1.83\) e,f,g & \(4.60\pm 1.94\) d & \(5.20\pm 1.74\) e,f \\ ColombiaCM & \(3.50\pm 2.01\) b & \(4.90\pm 2.09\) d & \(5.35\pm 1.72\) d,ef \\ FolgersCB & \(4.13\pm 2.13\) c,d & \(5.83\pm 1.76\) b & \(5.53\pm 1.49\) c,d,e \\ FolgersCM & \(3.18\pm 2.01\) b & \(6.84\pm 1.72\) a & \(6.00\pm 1.59\) b \\ KenyaCB & \(3.53\pm 1.87\) f,b & \(4.36\pm 1.94\) e,f & \(5.40\pm 1.60\) d,ef \\ KenyaCM & \(3.10\pm 1.93\) h & \(5.04\pm 2.14\) d & \(5.82\pm 1.51\) b,c \\ BaristaRTD(A) 3 & \(5.54\pm 2.15\) a & \(4.23\pm 1.82\) e,f & \(5.18\pm 1.74\) e,f \\ BaristaRTD(B) & \(5.80\pm 1.90\) a & \(4.14\pm 1.77\) e,f & \(5.01\pm 1.79\) f \\ BabinskiRTD & \(5.50\pm 2.04\) a & \(3.89\pm 1.73\) f & \(5.18\pm 1.61\) e,f \\ FrenchCafeRTD & \(4.65\pm 2.09\) b,c & \(4.07\pm 1.81\) f & \(5.54\pm 1.66\) c,d,e \\ StarbucksCS & \(4.05\pm 2.12\) d,e,f & \(625\pm 1.82\) b & \(6.01\pm 1.42\) a,b \\ TwosomeplecSC & \(4.76\pm 2.47\) b & \(5.69\pm 1.97\) c & \(6.41\pm 1.68\) a \\ \hline \hline \multicolumn{1}{c}{\(p\)-value} & \(<\)0.0001 & \(<\)0.0001 & \(<\)0.0001 \\ LSD & 0.52 & 0.47 & 0.41 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Mean intensity of consumers’ overall liking, bitter intensity, and coffeeID intensity of coffee samples.  
Figure 1: (a) Principal component analysis (PCA) of coffee samples and volatile compounds and (b) confidence ellipses map of the samples. V1–V36 stands for each volatile compound numbering in Table 4.  
Relationship between Sensory Data, Volatiles, and Caffeine, Chlorogenic Acid, and Trigonelline Compounds in Coffee