## 3 Results and Discussion
### Volatile Compounds in CB Coffee Samples
Phenol (V8), which is related to phenol materials ([PERSON] et al., 2018) and smoky ([PERSON] et al., 2018), burning taste, coal tar odor ([PERSON] et al., 2018), also showed higher amounts in CS and Folgers samples. Pyrroles are usually related to nutty, hay-like, and herb aroma. First, 1-Furfuryl pyrrole (V26), which has hay-like, mushroom, and green characteristics [26], was higher in FolgersCM. In the case of 2-acetylepyrrole (V14), CS and Folgers samples showed higher contents. With respect to tetradecanoic acid (V36), which was reported to be associated with faint odor [30], only ColombiaCB and KenyaCB contained about 1 ng/mL. The concentration of 3,5-ocatadien-2-one (V15) was higher in ColombiaCB and KenyaCB than in other samples. Maltol (V23) is associated with caramel-like odor and chocolate flavor [30]. When in solution, it exhibits fruity characteristics, especially when the concentration is below 20 ppm [28]. StarbucksCS had a higher amount of maltol, followed by TwosomeplaceCS, ColombiaCM, and KenyaCM showed lower contents than those of ColombiaCB and KenyaCB. These volatile compound patterns suggested that the Colombia and Kenya samples were more influenced by the extraction method than the origin of coffee. [PERSON] et al. [33] compared the contents of aroma compounds in brewed coffee. Among the key aroma compounds that they reported, guaiacol (V20) and maltol (V23) were identified in our coffee samples. In their study, guaiacol (V20) and maltol (V23) contents detected by LLE--GC--MS were higher in the Kenya brewed coffee sample than in the Colombia brewed coffee sample. Similarly, Kenya samples had higher amounts of guaiacol (V20) and maltol (V23) than those in Colombia samples, regardless of the extraction method (CB and CM) in this study. This result might be due to the difference in coffee bean components that affect volatile compounds rather than the difference in extraction methods. Nonanal (V22) is related to citrus, fat, and green attributes [32]. KenyaCB (2 ng/mL), ColombiaCB and CM (0 and 3 ng/mL, respectively), FrenchCafeRTD (3 ng/mL), and BabinskiRTD (2 ng/mL) are more likely to have a refreshing, citrus, and waxy taste because n-nonanal showed these characteristics when it was below a concentration of 5 ppm [28]. Nonanoic acid (V28) is also related to green, fatty, and bitterness, and this compound was found in higher concentrations in FolgersCM and StarbucksCS. Decanoic acid (V32), which had rancid fatty notes [28] were present in slightly higher amounts in FolgerCM and StarbucksCS samples. Although there were no peppermint-like attributes, ColombiaCB and FolgersCB showed slightly higher amounts of methyl salicate (V27), which is associated with peppermint characteristics [32]. The results of volatile compounds showed that CS and Folgers samples had higher amounts of volatiles than those in RTD samples. Specifically, RTD samples, except BaristaRTD, generally had lower contents of most volatile compounds, which corresponded with non-volatile compounds, showing the lowest contents in RTD samples. [PERSON] and [PERSON] [34] suggested that heat treatment for sterilization could affect the sensory aspect of canned coffee. The results of sensory evaluation showed significant differences between heated coffee and non-heated coffee samples. Furthermore, after heat treatment, 3-methylbutanoic acid, and another \"unknown\" compound related to sour odor were identified by gas chromatography-olfactometry (GC-O). Although coffee volatiles that were affected by heat processing might vary according to coffee variety or specific brewing preparation, some volatile compounds of RTD could change. [PERSON] and [PERSON] [35] compared the concentrations of volatile compounds in Turkish coffee and French press coffee. The results showed that volatile profiles of both coffee samples were similar, but there were still a few differences in the volatile compounds and concentrations. This research suggests that the brewing method could influence volatile profiles.