## 3 Results and Discussion
### Volatile Composition of Single-Dose Espresso Coffee-Based Blends
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Compound** & **CAS Number** & **Reported \({}^{*}\)** & **Aroma Descriptor \({}^{b}\)** & **References \({}^{*}\)** \\ \hline _Sesquierrepens_ & & & \\ \hline _a_-Cubehene & 17699-14-8 & & - \\ _a_-Copehene & 3865-25-5 & [29] & - \\ _Longidione_ & 475-20-7 & & - \\ _b_-Caryophyllene & 87-44-5 & & Cloves, twtpentine & [36] \\ _a_-Humulene & 6733-86-6 & & - \\ _a_-Muurclone & 31983-22-9 & & - \\ _c_-Calchinee & 483-76-1 & [29] & - \\ \hline _Nonisoprenoids_ & & & \\ \hline _Vitigiprane_ (C\({}_{13}\)) & 65416-59-3 & & - \\ _Thespirane_ (C\({}_{13}\)) & 36431-72-8 & & - \\ _1,2-Dhyhydro-1,1,6-trimethylnaphthalene_ (C\({}_{13}\)) & 30364-38-6 & & \\ _b_-Damascene_ (C\({}_{13}\)) & 23726-934 & [33] & Tea-like, fruity, honey-like, fruity, sweet-fruity & [2,39,44,50,52, 60,62] \\ _a_-Ionenne_ (C\({}_{13}\)) & 127-41-3 & & Warm, woody, berry characteristic violet-like & [36] \\ _Geranyl acetone_ (C\({}_{13}\)) & 6897-67 & & Green, rosy floral, fresh-flav, sweet-roy, slightly & [36] \\ \hline _Thiazoles_ & & & \\ \hline _Thiazole_ & 288-47-1 & [33] & Green, sweet, nutity, tomato, toasted & [20,36] \\ _2_-Methylthiazol_ & 3581-87-1 & [33] & - & - \\ _4_-Methylthiazol_ & 693-95-85 & [33] & Nutty, green, roasted & [36,54] \\ _5_-Methylthiazol_ & 3581-89-3 & [33] & - & - \\ \(2\),4-Dimethylthiazol_ & 541-58-2 & [33] & Salty, sulfury, burnt, rubber & [37] \\ \(2\),5-Dimethylthiazol_ & 475-66-0 & [33] & & \\ \(4\),5-Dimethylthiazol_ & 3581-91-7 & [33] & Roasted nutty, boiled poultry & [36] \\ _5_-Ethylthiazol_ & 17626-73-2 & [33] & - & - \\ _Ethyl-+methylthiazol_ & 15679-12-6 & [33] & Nutty, green & [36] \\ _5_+Propylthiazole_ & 41981-60-6 & & - & \\ _5_-Ethyl-2_methylthiazol_ & 1991-52-5 & [33] & Ruben-like & [2] \\ _2_-isopropyl-2_methylthiazol_ & 15679-13-7 & & Green, vegetable, nutity, roofy, earthly & [36] \\ _5_-Ethyl-4_methylthiazol_ & 31883-01-9 & [33] & Nutty, green, earthly & [36] \\ _2_-Acetylthiazol_ & 2425-03-2 & [33] & Green onion, herbal, grassy & [36] \\ _Ethyl-2_5-dimethylthiazol_ & 32272-67-4 & [33] & & \\ _5_-Ethyl-2_4-dimethylthiazol_ & 38205-61-7 & [33] & Earthy, roasty & [39] \\ _2_-Acetyl+methylthiazol_ & 7533-07-5 & [33] & - & - \\ _2_-Propranolol-thiazol_ & 43039-98-1 & & & \\ _Benozothiazole_ & 95-16-9 & [33] & Delicate, persistent, rose-like & [36] \\ \hline \multicolumn{2}{c}{**Tiophene compounds**} & & & \\ \hline _Thiophene_ & 110-02-1 & [33] & - & - \\ _2_-Methylthiophene_ & 554-14-3 & [33] & Onion, sulfury & [60] \\ _3_-Methylthiophene_ & 616-44-4 & [33] & - & - \\ _2_-Ethylthiophene_ & 872-55-9 & [2,49] & - & - \\ _2_-Dimethylthiophene_ & 638-02-8 & [37] & - & \\ _2_-Dimethylthiophene_ & 638-00-6 & & - \\ _2_-Dimethylthiophene_ & 632-16-6 & [37] & - & \\ _2_-Vinylthiophene_ & 1918-82-7 & [37] & - & \\ _3_-Methyl-Morphone_ & 17573-92-1 & & - & \\ _3_-Thiophene_ & 1003-04-9 & [33] & Garlic meaty, green vegetable, buttery & [36] \\ _2_-Isopropylthiophene_ & 4095-22-1 & & - & - \\ _2_-3_-Trimethiophene_ & 1759-04-6 & & - \\ _Dihydro-2_methyl-3_(2H)-thiophenone_ & 13679-85-1 & [33] & - & - \\ _3_-Thiophene_vacaldehyde_ & 498-62-4 & & - & \\ _Dihydro-2_(3H)-thiophenone_ & 1003-10-7 & [33] & & - \\ _2_-Thiophene_vacaldehyde_ & 98-03-3 & [33] & Coffee & [20] \\ _3_-Methyl-2_thiophenone_ & 1468-33-6 & [33] & - & - \\ _3_-Acetylthiophene_ & 1468-33-3 & [33] & - & - \\ _2_-Acetylthiophene_ & 88-15-3 & [33] & - & - \\ _2_-5_Distribiophene_ & 5009-23-8 & & - & - \\ _Methyl-2_-thiophene_ carboxylate_ & 5380-42-7 & [33] & - & - \\ _5_-Methyl-2_-thiophenone_vacaldehyde_ & 13679-70-4 & [33] & - & - \\ _2_-Penylthiophene_ & 4861-58-9 & & - & - \\ _2_-Propionylthiophene_ & 13679-75-9 & [33] & - & - \\ \hline \hline \end{tabular}  
* Compounds previously identified in roasted coffee and/or brews. \({}^{b}\) Aroma descriptors and \({}^{c}\) corresponding references of each volatile compound, determined in aqueous conditions.  
\end{table} 
Table 1: _Cont._and green notes related to 2,5-diethyltetrahydrorofuran and 2-isopropyl-4-methylthiazolole (Table 1).