## 3 Results and Discussion
### Caffeine, Chlorogenic Acid, and Trigonelline Compounds in CB Coffee Samples
Thus, the low caffeine content in RTD samples in this study may be explained by the different grinding levels and brewing times of different manufacturing companies. Blended CB and CM samples underwent a higher intensity of roasting than that for the Colombia and Kenya samples, which may explain the lower chlorogenic acid contents in the CM samples. This result agrees with those of other studies (e.g., [PERSON] et al. [20] and [PERSON] and [PERSON] [3]). According to their studies, chlorogenic acid can be degraded (\(>\)90%) by thermal processing such as dark roasting, suggesting that the roasting time and temperature influence the chlorogenic-acid content in coffee products [21; 22]. Trigonelline contributes to the overall aroma perception of brewed coffee [23]. Usually, it has a very weak bitter taste, but it degrades rapidly during the roasting process and produces impactful volatile compounds such as pyridines and pyrroles [3]. The lower chlorogenic-acid and trigonelline \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample Name** & **Caffeine** & **Chlorogenic Acid** & **Trigonelline** \\ \hline BlendingCB & 0.80 \(\pm\) 0.04 \({}^{\mathrm{d}}\) & 0.21 \(\pm\) 0.03 \({}^{\mathrm{c,d,e}}\) & 0.25 \(\pm\) 0.03 \({}^{\mathrm{d}}\) \\ ColombiaCB & 0.63 \(\pm\) 0.03 \({}^{\mathrm{f}}\) & 0.21 \(\pm\) 0.01 \({}^{\mathrm{d,e}}\) & 0.25 \(\pm\) 0.03 \({}^{\mathrm{d}}\) \\ FolgersCB & 0.95 \(\pm\) 0.04 \({}^{\mathrm{b}}\) & 0.25 \(\pm\) 0.02 \({}^{\mathrm{a,b}}\) & 0.29 \(\pm\) 0.02 \({}^{\mathrm{b,c}}\) \\ KenyaCB & 0.75 \(\pm\) 0.02 \({}^{\mathrm{d,e}}\) & 0.23 \(\pm\) 0.01 \({}^{\mathrm{a,b}}\) & 0.28 \(\pm\) 0.02 \({}^{\mathrm{b,c}}\) \\ BlendingCM & 0.77 \(\pm\) 0.07 \({}^{\mathrm{d,e}}\) & 0.18 \(\pm\) 0.02 \({}^{\mathrm{f,g}}\) & 0.19 \(\pm\) 0.03 \({}^{\mathrm{e}}\) \\ ColombiaCM & 0.74 \(\pm\) 0.04 \({}^{\mathrm{e}}\) & 0.23 \(\pm\) 0.01 \({}^{\mathrm{b,c,d}}\) & 0.27 \(\pm\) 0.03 \({}^{\mathrm{c,d}}\) \\ FolgersCM & 1.05 \(\pm\) 0.04 \({}^{\mathrm{a}}\) & 0.25 \(\pm\) 0.02 \({}^{\mathrm{a}}\) & 0.31 \(\pm\) 0.04 \({}^{\mathrm{a,b}}\) \\ KenyaCM & 0.76 \(\pm\) 0.03 \({}^{\mathrm{d,e}}\) & 0.23 \(\pm\) 0.01 \({}^{\mathrm{b,c,d}}\) & 0.27 \(\pm\) 0.03 \({}^{\mathrm{c,d}}\) \\ BabinskiRTD & 0.63 \(\pm\) 0.06 \({}^{\mathrm{f}}\) & 0.16 \(\pm\) 0.02 \({}^{\mathrm{g}}\)h & 0.18 \(\pm\) 0.03 \({}^{\mathrm{e}}\) \\ BaristaRTD & 0.59 \(\pm\) 0.04 \({}^{\mathrm{f}}\) & 0.10 \(\pm\) 0.01 \({}^{\mathrm{i}}\) & 0.11 \(\pm\) 0.02 \({}^{\mathrm{f}}\) \\ FrenchCafeRTD & 0.61 \(\pm\) 0.03 \({}^{\mathrm{f}}\) & 0.13 \(\pm\) 0.01 \({}^{\mathrm{h}}\) & 0.14 \(\pm\) 0.02 \({}^{\mathrm{f}}\) \\ StarbucksCS & 0.97 \(\pm\) 0.04 \({}^{\mathrm{b}}\) & 0.25 \(\pm\) 0.03 \({}^{\mathrm{a}}\) & 0.33 \(\pm\) 0.01 \({}^{\mathrm{a}}\) \\ TwosomeplaceCS & 0.87 \(\pm\) 0.03 \({}^{\mathrm{c}}\) & 0.19 \(\pm\) 0.04 \({}^{\mathrm{e,f}}\) & 0.26 \(\pm\) 0.05 \({}^{\mathrm{c,d}}\) \\ \hline \(p\)-value & \(<\)0.0001 & \(<\)0.0001 & \(<\)0.0001 \\ LSD & 0.05 & 0.03 & 0.04 \\ \hline \hline \end{tabular} \({}^{\mathrm{1}}\) CB stands for cold brew; CM stands for coffee maker brewed (hot); RTD stands for ready-to-drink; CS stands for coffee shop samples. \({}^{\mathrm{2}}\) Mean \(\pm\) SD. \({}^{\mathrm{3}}\) Same characters in the same column mean no significant difference by ANOVA at 95% confidence level.  
\end{table} 
Table 3: Mean amount of caffeine, chlorogenic acid, and trigonelline of CB coffee samples (mg/mL) [1; 2; 3]. contents in RTD samples can possibly be ascribed to several thermal processes during manufacturing because both chlorogenic and trigonelline were vulnerable to thermal processes such as roasting. Degradation during processing could also be considered a reason for the reduced amount of chlorogenic acid in the RTD samples. Additionally, according to a study conducted by [PERSON] et al. (2018), caffeine, chlorogenic acid, and trigonelline contents increased with a decrease in particle size of the espresso coffee samples.