## 4 Discussion
Recent research has shown that levels of 2-ethyl-5-methylpyrazine and 2,5(6)-dimethylpyrazine tend to be slightly higher in fermented coffees [34; 35], which may explain the elevated presence of 2-ethyl-5-methylpyrazine and 3-ethyl-2,5-dimethylpyrazine in civet coffee, given its more extensive fermentation process. Interestingly, only 3-ethyl-2,5-dimethylpyrazine was detected in elephant coffee, which might be due to 2-ethyl-5-methylpyrazine being more susceptible to degradation during digestion, considering the significantly longer gastrointestinal tract of elephants. This hypothesis is supported by evidence that a structural analogue, 2,3-diethyl-5-methylpyrazine, can be degraded by mycobacteria [36]. While this bacterium is linked to pathogenic intestinal conditions such as inflammatory bowel disease, it is likely not the only microorganism capable of breaking down this compound. Furthermore, recent studies have noted an increase in 3-ethyl-2-hydroxy-2-cyclopenten-1-one in fermented coffees [37; 38]. In our study, this compound was elevated in civet coffee but absent in elephant coffee, suggesting it may undergo a similar degradation pathway as 2-ethyl-5-methylpyrazine. Additionally, unfermented coffees tend to have higher levels of furuns but generally lower amounts of furfuryl acetate [34], which aligns with our findings where both civet and elephant coffees contained significantly less 5-methylfurfural but higher levels of furfuryl acetate. It thus appears that animal-derived coffees have higher levels of certain pyrazines, aliphatic compounds, and furans, alongside lower caffeine and antioxidant contents. This trend is evident in civet coffee but seems even more pronounced in elephant coffee, likely due to the elephant's larger gastrointestinal tract and the increased fermentation of coffee beans in their gut. This is further supported by the fact that elephants are hindgut fermenters, relying heavily on gastrointestinal microflora for digestion because of their limited production of digestive enzymes [39]. Previous studies [22; 23] identified compounds such as 3-methyl-1-butanol, 2-methyl-1-butanol, 2-furfurylfuran, 3-penten-2-one, 2-hydroxymethylpyrrole, 3-methylfuran, 2-methylfuran, and 2-ethyl-3-methylpyrazine as unique to elephant coffee. While our findings partially align with this, these compounds were also detected, to some extent, in other coffee samples, suggesting they cannot be considered definitive markers. Unlike earlier research, we did not identify any conclusive markers for authenticating elephant coffee. This may be due to factors such as the limited sample size. However, it is important to note that previous studies also worked with small sample sets and similar analytical methods, like GC-MS. Therefore, we propose that authenticating elephant coffee is likely more complex than previously thought and will require more advanced, comprehensive approaches, such as metabolomics or NMR-based profiling applied to larger sample groups [40]. This remains a challenge, especially since there is currently only one commercial supplier of elephant coffee worldwide. It thus seems that animal-derived coffee has increased content of selected pyrazines and aliphatic compounds, furans, and lower amounts of caffeine and antioxidants. This trend was also found in the case of civet coffee but appears to be more profound in elephant coffee, presumably mainly due to the larger gastrointestinal tract and increased fermentation rate of the coffee bean in the gut. This assumption is further supported by the fact that elephants (in comparison to civets) are hindgut fermenters and rely heavily on gastrointestinal microflora for digestion (fermentation), due to their limited production of digestive enzymes [39]. Previous studies [22; 23] have shown that some compounds, e.g., 3-methyl-1-butanol, 2-methyl-1-butanol, 2-furfurylfuran, 3-penten-2-one, 2-hydroxymethylpyrrole, 3-methylfuran, 2-methylfuran, 2-ethyl-3-methylpyrazine, 2-hexanol are exclusively specific to elephant coffee.