## 3 Results and Discussion
### Headspaces Chemical Composition
#### 3.2.2 Beverages
\begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{**1.r.i. 1**} & \multirow{2}{*}{**Class.**} & \multicolumn{2}{c}{**Relative Abundance (\%) \(\pm\) SD**} \\ \cline{3-5}  & & & **CTR Beer** & **Hibiscus Beer** \\ \hline acetic acid & 603 & nt & \(4.9\pm 0.39\) 2 & -33b \\
**ethyl acetate** & **743** & **nt** & \(\mathbf{14.6\pm 1.36}\) 2 & \(\mathbf{30.4\pm 3.11}\)2 \\
**isoamyl alcohol** & **736** & **nt** & \(\mathbf{15.5\pm 1.47}\) & \(\mathbf{13.7\pm 1.54}\) \\
**2-methylbutanol** & **737** & **nt** & \(\mathbf{4.4\pm 0.23}\) & \(\mathbf{4.4\pm 0.68}\) \\
1-pentanol & 765 & nt & \(0.1\pm 0.00\) & - \\ isobutyl acetate & 771 & nt & \(0.9\pm 0.06\) & \(0.7\pm 0.10\) \\
**ethyl butyrate** & **862** & **nt** & \(\mathbf{1.6\pm 0.12}\) 2 & \(\mathbf{1.1\pm 0.08}\)2 \\
**isopentyl acetate** & **876** & **nt** & \(\mathbf{7.7\pm 0.55}\) 2 & \(\mathbf{10.6\pm 0.28}\)2 \\
2-methylbutanol acetate & 880 & nt & \(1.2\pm 0.04\) & \(1.0\pm 0.17\) \\
**styrene** & **893** & **nt** & \(\mathbf{2.1\pm 0.07}\) & \(\mathbf{2.2\pm 0.88}\) \\
**mycene** & **991** & **mh** & \(\mathbf{2.2\pm 0.30}\) 2 & \(\mathbf{0.5\pm 0.27}\)2 \\
**ethyl hexanoate** & **998** & **nt** & \(\mathbf{8.6\pm 0.40}\) 2 & \(\mathbf{7.0\pm 0.23}\)2 \\ ethyl heptanoate & 1101 & nt & \(0.3\pm 0.06\) & \(0.2\pm 0.06\) \\ nonanal & 1105 & nt & \(0.1\pm 0.21\) & \(0.1\pm 0.03\) \\ phenylethyl alcohol & 1114 & nt & \(0.9\pm 0.19\) & \(0.7\pm 0.04\) \\
**ethyl octanoate** & **1199** & **nt** & \(\mathbf{26.4\pm 1.14}\) 2 & \(\mathbf{21.4\pm 1.89}\)2 \\ decanal & 1206 & nt & - & \(0.2\pm 0.03\) \\
2-phenylethyl acetate & 1257 & nt & \(0.1\pm 0.01\) & - \\ ethyl nonanoate & 1296 & nt & \(0.1\pm 0.01\) & \(0.1\pm 0.02\) \\ ethyl 9-decenoate & 1387 & nt & \(1.3\pm 0.16\) & \(1.2\pm 0.12\) \\
**ethyl decanoate** & **1396** & **nt** & \(\mathbf{5.5\pm 1.27}\) & \(\mathbf{3.9\pm 0.68}\) \\ \(\beta\)-caryophyllene & 1419 & sh & \(0.2\pm 0.10\) & \(\mathbf{0.3\pm 0.15}\)2 \\
**\(\alpha\)-humulene** & **1453** & **sh** & \(\mathbf{1.1\pm 0.42}\) 2 & \(\mathbf{0.3\pm 0.15}\)2 \\ \hline Total identified (\%) & & & 100.0 \(\pm\) 0.01 & 99.9 \(\pm\) 0.04 \\ \hline Monoterpenes & & & 2.1 \(\pm\) 0.14 2 & \(0.5\pm 0.27\)2 \\ hydroocarbons (mh) & & & & \\ Sesquireren & & & & \\ hydrocarbons (sh) & & & & \\ Other non-terpene & & & 96.4 \(\pm\) 0.80 2 2 & 99.0 \(\pm\) 0.41 2 \\ derivatives (nt) & & & & \\ _Acids_ & & 4.9 \(\pm\) 0.39 2 & -2 \\ _Alcohols_ & & 20.9 \(\pm\) 1.28 & 18.8 \(\pm\) 2.19 \\ _Esters_ & & 68.4 \(\pm\) 0.51 2 & 77.6 \(\pm\) 1.13 2 \\ _Aldehydes_ & & 0.1 \(\pm\) 0.21 & 0.3 \(\pm\) 0.03 \\ _Hydrocarbons_ & & 2.1 \(\pm\) 0.07 & 2.2 \(\pm\) 0.88 \\ \hline \hline \end{tabular} \({}^{\dagger}\) Linear retention index on a HP 5-MS capillary column. 2 Compounds accounting for at least 1.00% of the dissimilarity contribution, assessed by the SIMPER test, are evidenced in bold. For these compounds and for the chemical classes, the superscript lowercase letters (a,b) indicate statistically significant differences between the control and the treated beers. The statistical significance of the relative abundances was determined by [PERSON]’s post hoc test, with \(p\leq 0.05\). 3 Not detected.  
\end{table} 
Table 4: Chemical composition of the headspaces of the beer samples. for pear-like hints [39]. Alcohols were also detected in appreciable relative amounts in both beers, accounting for up to 20.9% in the CTR beer and 18.8% in the hibiscus beer. However, there was no relevant qualitative variability within this chemical group, as only four volatile organic compounds (VOCs) were identified, of which only isoamyl alcohol (CTR = 15.5%; Hibiscus = 13.7%) and 2-methylbutanol (amyl alcohol) (both 4.4%) were detected in substantial amounts. Higher alcohols, together with esters, are among the major chemical classes responsible for fruity and floral notes in beer aromas.