## 3 Results and Discussion
### Volatile Organic Compounds
Aldehydes contribute remarkably to citrus, fruity, floral, fresh, and herbaceous notes [55]. Some of these com  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & & & & & & & \multicolumn{3}{c}{_Samples_} \\ \cline{6-13}  & & & & & & & & & & & & \\ \hline
**Volatile Compound** & **Odor Description** & **\({}^{\star}\)CAS\#** & \({}^{\text{b}}\)ELRI & \({}^{\star}\)LRI & **1** & **2** & **3** & **4** & **5** & **6** \\ \hline
**Alcohols** & & & &  
pounds, such as octanal, decanal and dodecanal, identified in this study, have been listed as impact compounds in citrus fruits and have attractive sensory qualities, according to aroma and flavor assessments [49; 50]. Octanal has also been listed as one of the main aromatic compounds responsible for the unique aroma of toasted mate leaf [51]. Hexanal, heptanal, nonanal and benzaldehyde have been listed as key aroma and flavor compounds in black tea [23; 52]. Hexanal has been previously identified in fresh _C. arabica_[45] and _C. canephora_[46] cherry pulps. Nonanal, which also has been identified in fresh _C. canephora_ cherry pulp [46], contributes to citrus, fresh, orange, and green characteristics [53; 54]. This aldehyde was the most relevant concerning the chromatogram peak areas in all evaluated teas, accounting, in the fermented samples, for 9-15% of the total chromatogram peak area and, in the unfermented samples, for 15-20%. Because of their high chemical reactivity, the concentration of aldehydes is significantly altered during thermal processing [56] and, therefore, boiling these teas is probably not recommended. Acids accounted for 11.0-33.4% of the total chromatogram peak area, with the highest percentages found in infusions from fermented teas, especially Samples 2 and 3. Acids contribute pungent, vinegar, sour, fermented, and acidic notes. Acetic acid, also identified in the fresh _C. canephora_ pulp [46], has been listed as a key aroma compound in fermented beverages [51]. Octanoic and nonanoic acids were the most relevant in all samples concerning peak area, except for Sample 5 (unfermented), in which decanoic acid was more relevant. These compounds generally impart acid, sweat, and fruit characteristics to the beverage [53; 54]. Alcohols accounted for 3.3-11.4% of the total peak area of the volatile fraction of different samples, with higher percentages in the infusions from fermented teas, especially Sample 2. Phenylethyl alcohol, identified in fresh _C. canephora_ pulp [46], has been reported as key aroma compound in black tea [23; 52]. Together with ethyl hexanol, it was the most relevant alcohol in all samples. Alcohols, in general, contribute honey, floral, fresh, rose, citrus and alcohol notes [53; 54]. Esters comprised 3.0-23.5% of the total peak area of the chromatograms. The highest percentages of esters were observed in the fermented infusions. These compounds are essential volatile components in many fruits, and most of them have a strong fruity and floral odor and contribute to the \"mature\" flavor [57; 58]. Methyl and ethyl salicate have been previously identified in fresh pulps of _C. archaea_[45; 59] and _C. canephora_[46]. Methyl salicate has also been identified in Pu-erh tea samples and reported as an important component for the overall tea aroma formation [60]. Terpenoids comprised 2.8-8.5% of the total peak area of the chromatograms. Although these compounds are characterized by poor aroma, they still impart sweet, citrus, fruity, woody, and herbal characteristics [55]. However, they are susceptible to degradation reactions when exposed to air (oxygen), light, heat and undergo consequent conversion to terpenic alcohols or oxides [55]. Linalool, the most relevant terpenoid in the cascara teas, has been identified in fresh _C. arabica_[45] and _C. canephora_[46] pulps. It has been reported as key aroma compound in black tea [23; 50; 52]. \(\beta\)-ionone, only identified in Sample 2 (fermented), has also been listed as one of the main aroma-active compounds in toasted mate leaf [49].