## 4 Discussion  
### Compounds Obtained by Hydrodistillation and SPDE  
A remarkable difference between the extraction techniques employed for the present work can be observed at a first glance: HS-SPDE was more sensitive to the more volatile compounds and hydrodistillation to the less volatile. For instance, cymene is the 11 th identified compound in the HS-SPDE samples while it is the fifth in the essential oils (Table 5). These results are logical, considering that HS-SPDE occurs at a lower temperature, and during a shorter extraction time, but within a hermetic vial, which prevents any losses  
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Compound**}} & **Average Odor** & **Minimum Odor** & \multirow{2}{*}{**Odor Characteristics b**} \\  & **Threshold (ppm) a** & & & \\ \hline Geraniol & 0.0066 & 0.001 & Rose, geranium, floral, sweet, fruity, citrus \\ Cymene \textless{p}-\textgreater{} & 0.0114 & 0.0062 & Lemon, fruity, fuel-like, sweet, herbal, spicy \\ Pinene \textless{a}-\textgreater{} & 0.014 & 0.0025 & Terpeny, fruity, sweet, green, woody, pine, citrus \\ Pentyl furan \textless{2}-\textgreater{} & 0.0145 & 0.0058 & Buttery, green bean \\ (\(\beta\))–Myrecene & 0.015 & 0.0012 & Metallic, untsy, geranium, sweet, fruity \\ Estragole & 0.016 & 0.006 & Liquorice, sweet, herbal, anise, spicy \\ Eucalyptusptol & 0.023 & 0.0011 & Camphor, minty, sweet, liquorice, pine \\ Safrole & 0.033 & 0.01 & Sweet, warm, spicy, woody, floral \\ Ocimee \textless{(E)}-\textgreater{} & 0.034 & 0.034 & Herphal, mild, citrus, sweet, orange, lemon \\ MethylSalicylate & 0.04 & 0.0349 & Wine, berry, warm, sweet, wintergreen \\ Heptadienal \textless{(}\text{(}\text{2}\text{,}\text{\text{\text{\text{\text{\text{\text{ \text{\text{\text  
of analytes. Some of the most volatile compounds in the essential oils could not be detected or identified either due to their low concentration or due to the saturated peak of the solvent (n-hexane) that covered them. Considering that mate tea traditional consecutive infusions are prepared while they are being drunk-- therefore with warm but not boiling water [13]--hydrodistillation at 100 \({}^{\circ}\)C would be less representative than HS-SPDE at 70 \({}^{\circ}\)C, which was performed closer to the temperature of consumption. Independently of the temperature, HS-SPDE applied to the analysis of the infusions themselves presents the advantage of analyzing the final product that is ingested (the infusion) instead of the ingredient (mate tea) used for preparing the beverage. In the essential oils, the 71 identified compounds showed generally similar mean relative areas in both samples. The exceptions, showing a difference larger than twofold (%) between samples A and B, were cynmee <o->, 3,5-octalori-2-one <(E,E)->, linalooloxide <(Z)->, safranal, damascenone, farnesylacetone, and methyl linolenate. Therefore, both products can be considered similar and the average peak areas between both essential oils (A and B) were considered suitable for evaluating the highest means (above 1%) for: linalool (18.1%); farnaseen (10.5%); squalene (6.6%); palmitic acid (4.5%); phytol (4.5%); terpineol <\(\alpha\)-> (3.4%); damascenone, <(Z)-> (3.2%); geraniol (3.2%); 3-heptadecene <(Z)-> (2.6%); meridolol <(E)-> (2.1%); farnesylacetone <(5E,9E)-> (1.9%); hexahydrofranesylacetone (1.6%); methyl linolenate (1.5%); dendrolasin (1.4%); nerol (1.3%); geranylacetone <(E)-> (1.2%); ionone <(E)-> (1.1%); and 6,9-heptadecadiene (1.1%). The HS-SPDE samples presented a total of 30 identified compounds, which showed always similar patterns of relative peak area, independently of tea sample (A or B) and infusion technique (SI or TCI).