## 3 Results and Discussion
### Volatile Compounds
#### 3.4.6 Ethyl Esters
\begin{table}
\begin{tabular}{l l c c c c c c c c c} \hline \hline  & & & & & \multicolumn{6}{c}{**Differences in Concentration**} \\ \cline{6-13}  & & & & & \multicolumn{3}{c}{**One-Way ANOVA**} & \multicolumn{3}{c}{**Two-Way ANOVA**} \\ \cline{6-13}
**Co.** & **Volatile Compounds** & **ID** & **LRI\({}_{\text{e}}\)** & **LRI\({}_{\text{l}}\)** & \multicolumn{3}{c}{**2021**} & \multicolumn{3}{c}{**2022**} & \\ \cline{6-13}  & & & & & **SCE** & **SPA** & **SCE** & **SPA** & **Y** & **H** & \(\mathbf{Y}\times\mathbf{H}\) \\ \hline AC01 & Propanoic acid & A, B, C & 1537 & 1540 & **5.02 \({}^{\text{a}}\)** & **3.36 \({}^{\text{b}}\)** & 7.42 & 6.62 & n.s. & **22** & n.s. \\ AC02 & Isobutyric acid & A, B, C & 1570 & 1570 & **1.95 \({}^{\text{b}}\)** & **3.11 \({}^{\text{a}}\)** & 11.81 & 13.68 & n.s. & **22** & n.s. \\ AC03 & Pivalic acid & B, C & 1581 & 1579 & 1.73 & 1.39 & 2.17 & 2.35 & n.s. & n.s. & n.s. \\ AC04 & 4-Methyl-3-pentenoic acid & B & 1595 & - & 1.50 & 2.14 & n.d. & n.d. & - & - & - \\ AC05 & Butyric acid (mg/L) \(\ddagger\) & A, B, C & 1617 & 1612 & 1.59 & 1.45 & 1.11 & 1.04 & n.s. & **22** & n.s. \\ AC06 & 2-Propenoic acid & B & 1641 & - & 0.74 & 0.75 & 1.18 & 1.21 & n.s. & **22** & n.s. \\ AC07 & Isovaleric acid & A, B, C & 1672 & 1675 & **181.2 \({}^{\text{a}}\)** & **128.5 \({}^{\text{b}}\)** & **30.03 \({}^{\text{b}}\)** & **56.14 \({}^{\text{a}}\)** & n.s. & **21** & * \\ AC08 & 2-Methylbutyric acid & B, C & 1675 & 1675 & **61.10 \({}^{\text{b}}\)** & **100.8 \({}^{\text{a}}\)** & n.d. & n.d. & - & - & - \\ AC09 & 2-Methylpropenoic acid & B & 1697 & - & 0.15 & 0.10 \({}^{\text{a}}\) & n.d. & n.d. & - & - & - \\ AC10 & Pentanoic acid & A, B, C & 1741 & 1751 & 3.24 & 2.65 & 3.64 & 4.89 & n.s. & n.s. & n.s. \\ AC11 & 2-Butenoic acid & B, C & 1780 & 1773 & n.d. & n.d. & 0.39 & 0.38 & - & - & - \\ AC12 & Isohexanoic acid & B, C & 1810 & 1809 & **0.39 \({}^{\text{a}}\)** & **0.27 \({}^{\text{b}}\)** & n.d. & n.d. & - & - & - \\ AC13 & Hexanoic acid (mg/L) \(\ddagger\) & A, B, C & 1617 & 1828 & 7.28 & 6.30 & **7.44 \({}^{\text{a}}\)** & **5.20 \({}^{\text{b}}\)** & **SCE** & n.s. & n.s. \\ AC14 & _transs_-Hexenoic acid & B, C & 1942 & 1948 & n.d. & n.d. & 0.04 & 0.05 & - & - & - \\ AC15 & 2-Ethlyhexanoic acid & B, C & 1953 & 1960 & 3.71 & 3.12 & 3.44 & 3.36 & n.s. & n.s. & n.s. \\ AC16 & Heptanoic acid & A, B, C & 1954 & 1955 & 4.62 & 4.51 & 5.57 & 5.98 & n.s. & n.s. & n.s. \\ AC17 & _transs_-2-Hexenoic acid & B, C & 1968 & 1967 & 0.53 & 0.46 & 0.73 & 0.96 & n.s. & **22** & * \\ AC18 & Octanoic acid (mg/L) \(\ddagger\) & A, B, C & 2043 & 2042 & **7.66 \({}^{\text{a}}\)** & **5.49 \({}^{\text{b}}\)** & **9.07 \({}^{\text{a}}\)** & **5.58 \({}^{\text{b}}\)** & **SCE** & n.s. & n.s. \\ AC19 & 3-Hydroxylicylic acid & B & 2099 & - & n.d. & n.d. & 0.22 & 0.39 & - & - & - \\ AC20 & 3-Octenoic acid & B & 2120 & - & 1.67 & 0.82 & 0.65 & 0.69 & n.s. & n.s. & n.s. \\ AC21 & Nonanoic acid & A, B, C & 2168 & 2168 & 21.43 & 39.04 & **37.86 \({}^{\text{a}}\)** & **24.07 \({}^{\text{b}}\)** & n.s. & n.s. & n.s. \\ AC22 & Decanoic acid (mg/L) \(\ddagger\) & A, B, C & 2257 & 2258 & 2.79 & 2.62 & **1.59 \({}^{\text{a}}\)** & **0.92 \({}^{\text{b}}\)** & **SCE** & **21** & n.s. \\ AC23 & 9-Decanoic acid & B, C & 2330 & 2335 & 13.41 & 16.99 & 1.95 & 2.74 & n.s. & **21** & n.s. \\ AC24 & Undecanoic acid & B, C & 2346 & 2359 & 0.04 & 0.01 & 0.33 & 0.32 & n.s. & **22** & n.s. \\ AC25 & Trideanoic acid & B, C & 2590 & 2651 & n.d. & n.d. & 0.21 & 0.46 & - & - & - \\ AC26 & Tetradecanoic acid & B, C & 2696 & 2693 & 0.63 & 0.52 & 0.12 & 0.10 & n.s. & **21** & n.s. \\ \hline \hline \end{tabular} Abbreviations: Co.–compound’s code; ID–identification of compounds: A–retention time accordant with that of a pure standard; B–mass spectra accordant with that from NIST 2,0, Wiley S, and FFNSC 2 mass spectra electronic libraries or literature; C–linear retention index (LRI) accordant with an index from literature (compounds with only B in the ID column were considered tentatively identified); LRI—experimental linear retention index; H\({}_{\text{l}}\)—linear retention index from literature; n.s.–not significant; n.d.—not detected. One-way ANOVA section: different superscript lowercase letters represent statistically significant differences between the two investigated wines determined by one-way ANOVA at \(p<0.05\) for each harvest year separately. Two-way ANOVA section: designations are reported representing yeast (SCE, SPA) and harvest year (21, 22) with higher concentration determined by two-way ANOVA at \(p<0.05\) with yeast (7) and harvest year (H) as factors. An asterisk indicates a significant interaction between the two factors (\(\mathbf{Y}\times\mathbf{H}\)). Significant differences are highlighted in bold.  
\end{table}