## 3 Results and Discussion
### Volatile Composition of Single-Dose Espresso Coffee-Based Blends
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Compound** & **CAS Number** & **Reported \({}^{\star}\)** & **Aroma Descriptor \({}^{\text{\text{\textregistered}}}\)** & **References \({}^{\text{\text{\textregistered}}}\)** \\ \hline
**Pyidines** & & & \\ \hline Pyridine & 110-86-1 & [33] & Pungent, nauseeting, warm, burnt, smoky, coffee-like & [20,34,36,54] \\
2-Methylpyridine & 109-06-8 & [33] & Roussed popcorn, coffee & [20,60] \\
2,6-Dimethylpyridine & 108-48-5 & [33] & Minty-tarrry, pyridine, peppermint & [36] \\
2-Ethpyridine & 107-71-0 & [33] & \\
3-Ethylpyridine & 536-78-7 & [33] & Tobacco, caramel, burnt, coffee-like, toasted & [20,36,54,60] \\
3-Vinylpyridine & 1121-55-7 & - & - \\
2-Acetylpyridine & 1122-62-9 & [33] & Popcorn, bready, tobacco, cracker-like, roasted barley & [36,60] \\ Methyl 3-pyridinccarboxylate & 93-60-7 & [33] & Nauseeating, sweet-herbaceous, mildly tobacco-like, fresh, caramel nutty & [34,36] \\
2-Perntlypyridine & 2294-76-0 & - & Tallowy-like & [36] \\ \hline
**Pyrocles** & & & \\ \hline
1-Methylpyrrole & 96-54-8 & [33] & Smoky-tarrry, sweet, woody-herbaceous, animal, coffee & [20,34] \\ Pyrrole & 109-97-7 & [33] & Warm, slightly pungent, hay-like herbaceous, sweet, green, toasted & [20,34,36,54] \\
1-Ethylpyrrole & 617-92-5 & [33] & - & \\
2,5-Dimethylpyrrole & 625-84-3 & [33] & - & \\
2-Ethyl+4-methylpyrrole & 69687-77-0 & [37] & - & \\
1-Acetylpyrrole & 609-41-6 & [33] & - & \\
3-Ethyl-2,4-dimethylpyrrole & 517-22-6 & [33] & - & \\
1-Methyl-2-formpyrrole & 1192-58-1 & [33] & Cracker-popcorn, burnt & [54,60] \\
1-Ethyl-2-formpyrrole & 2167-14-8 & [33] & - & \\
2-Acetyl-1-methylpyrrole & 932-16-1 & [33] & - & \\
2-Acetylpyrrole & 1072-83-9 & [33] & Bread, walnut, licorice, cracker, popcorn-like & [20,36,60] \\ \hline
**Sulfur compounds** & & & \\ \hline Dimethyl disulfide & 624-92-0 & [33] & Onion & [34,36] \\ Methylthio-2-propanone & 14109-72-9 & Melon & [36] \\
2-Furylmethylsulfide & 13129-38-9 & [33] & Garlic-like & [60] \\
2-Fururylmethylthiol & 99-02-2 & [33] & Coffee-like, burnt-camellar-like, sweet, roasty, sulfury & [44,34,34,54] \\
3-Methylthiopropanol (Methion) & 3268-49-3 & [33] & Onion, meat-like, boulin-like, soup-like, cooked & [44,34,36,38,46] \\
1-Methylthio-2-butanone & 13678-58-5 & [33] & Mushroom, garlic & [36,60] \\ Dimethylsulfide & 3658-80-8 & [33] & Fresh onion, cabbage-like, brothy, salivary, pungent & [4,34,36,37] \\
3-Mercapto-3-methyl-1-butanol & 34300-94-2 & [33] & Sweet, soup-like, cooked meat, spicy, smoke-roast, & [37,52,60] \\  & & meat, chicken brothy & & \\
2-Furfuryl methyl sulfide & 1438-91-1 & [33] & Coffee-like, onion, garlic, burnt, sulfury, & [20,36,37,60] \\  & & cooked cabbage & & \\
3-Mercapto-3-methylburl formate & 50/746-10-6 & [33] & Sweaty, fruity, blackcurant-like, catty, & [4,39,44,52,60] \\
3-Mercapto-3-methylburl acetate & 50/746-09-3 & [65] & - & \\ \hline Furfuryl methyl disulfide & 57500-00-2 & [33] & Fresh white bread crust & [60] \\ \hline
**Terpenic compounds** & & & \\ \hline \multicolumn{4}{c}{_Monoterpenses_} & & \\ \hline \multicolumn{4}{c}{\(\alpha\)-Fineinee & 80-56-8 & [19] & Pine, turpentine-like & [36] \\ \multicolumn{4}{c}{\(\beta\)-Finee & 127-91-3} & [19] & Turpentine, dry, woody, resinous & [36] \\
2,6-Dimethyl\(\beta\)-2-6-cadiene (isomer) & 2729-39-4 & - & - & \\ \multicolumn{4}{c}{\(\beta\)-Myrene} & 123-35-3 & [33] & Sweet, balsamic, plastic, sweet-balsamic- resinous gum & [34,36] \\
2,6-Dimethyl\(\beta\)-2-6-cataloine (isomer) & 2792-39-4 & - & - & \\ \multicolumn{4}{c}{\(\alpha\)-Phellandrene} & 99-83-2 & [66] & Fresh, citrus, peppery, discrete mint, minity, & \\ \multicolumn{4}{c}{\(\alpha\)-Terpinene} & 99-86-5 & [19] & Wood, terpene, lemon & [36] \\ \multicolumn{4}{c}{\(\gamma\)-Cyrene} & 99-87-6 & [33] & Carrot-like, kerosene-like & [34,36] \\ \multicolumn{4}{c}{Limonene} & 138-86-3 & [33] & Citrus, lemon-like, fresh, sweet & [60] \\ \multicolumn{4}{c}{\(\beta\)-Coimeene (isomer)} & 13877-91-3 & [49] & Warm herbaceous & [36] \\ \multicolumn{4}{c}{\(\beta\)-Coimeime (isomer)} & 13877-91-3 & [49] & Warm herbaceous & [36] \\ \multicolumn{4}{c}{\(\gamma\)-Terpinene} & 99-85-4 & [19] & Lemon & [36] \\ \multicolumn{4}{c}{\(\alpha\)-Terpinene} & 586-62-9 & - & Sweet, pine & [36] \\ \multicolumn{4}{c}{\(P\)-Cymenene} & 1195-32-0 & [33] & Citrus-ly-lemon-like, gassy & [34] \\ \multicolumn{4}{c}{\(\alpha\)-Cosme} & 460-01-5 & - & - & \\ \multicolumn{4}{c}{\(\Delta\)-o-cidemene} & 673-84-7 & - & - & \\ \hline \multicolumn{4}{c}{_Monoterpensuits_} & & & \\ \hline Linalool oxide (isomer) & 1365-19-1 & [33] & Sweet, woody, floral, woody-earthy & & [34,36] \\ \multicolumn{4}{c}{\(\beta\)-Coime} & 1365-19-1 & [33] & Water, woody, floral, woody-earthy & & [34,36] \\ \multicolumn{4}{c}{\(\beta\)-Coime} & 1387-70-6 & [33] & Floral-wood, faintly ctruswote, fioral, sweet-fruity & [34,36,39,50,52] \\ \multicolumn{4}{c}{\(\alpha\)-Terpine} & 98-55-5 & [33] & Floral, lilac & [60] \\ \multicolumn{4}{c}{\(p\)-Menth-1-1-en-9-al} & 29548-14-9 & - & - & \\ \hline \hline \end{tabular}
\end{table}