## 2 Results
### The Content of Volatile Compounds in Apple Wines  
The profile of volatile compounds responsible for the odour was determined using the SPME-GC-MS method (Table 4). Additionally, odour activity values (OAVs) were calculated by dividing the concentrations of aroma compounds by their sensory thresholds (taken from the literature). Only volatiles with an OAV > 1 can be perceived and contribute to the overall aroma of the wine. Therefore, the concentration values that give an OAV greater than 1 are highlighted in green in the table. The wines were dominated by alcohols, primarily amyl alcohols, isobutyl alcohol and phenylethyl alcohol. Esters, terpen and aldehydes occurred in lower concentrations (Table 4). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Wood Species** & **Toasting Level** & **L* & **a* & **b* \\ \hline \multirow{3}{*}{Oak} & Lightly & 94.23 \(\pm\) 0.41 a & 1.28 \(\pm\) 0.22 a & 10.38 \(\pm\) 1.63 a \\  & Medium & 94.46 \(\pm\) 0.20 a & 0.99 \(\pm\) 0.20 a & 8.53 \(\pm\) 1.26 b \\  & Heavily & 94.55 \(\pm\) 0.13 a & 0.80 \(\pm\) 0.15 a & 7.59 \(\pm\) 0.95 b \\ \hline \multirow{3}{*}{Maple} & Lightly & 94.48 \(\pm\) 0.27 a & 0.86 \(\pm\) 0.30 a & 7.39 \(\pm\) 1.52 b \\  & Medium & 94.46 \(\pm\) 0.08 a & 0.82 \(\pm\) 0.10 a & 7.51 \(\pm\) 0.77 b \\  & Heavily & 94.51 \(\pm\) 0.25 a & 0.97 \(\pm\) 0.18 a & 8.56 \(\pm\) 1.07 b \\ \hline \multirow{3}{*}{Apple} & Lightly & 94.72 \(\pm\) 0.21 a & 0.74 \(\pm\) 0.25 b & 7.74 \(\pm\) 1.79 b \\  & Medium & 94.63 \(\pm\) 0.25 a & 0.79 \(\pm\) 0.15 b & 7.54 \(\pm\) 0.85 b \\  & Heavily & 94.62 \(\pm\) 0.10 a & 0.73 \(\pm\) 0.12 b & 7.31 \(\pm\) 0.86 b \\ \hline \multirow{3}{*}{Cherry} & Lightly & 94.36 \(\pm\) 0.22 a & 0.82 \(\pm\) 0.17 a & 7.41 \(\pm\) 1.09 b \\  & Medium & 94.38 \(\pm\) 0.10 a & 0.95 \(\pm\) 0.19 a & 8.04 \(\pm\) 1.10 b \\  & Heavily & 94.48 \(\pm\) 0.19 a & 0.83 \(\pm\) 0.15 a & 7.87 \(\pm\) 0.90 b \\ \hline \multicolumn{3}{c}{Barrel} & — & 89.27 \(\pm\) 0.82 b & 5.02 \(\pm\) 0.73 c & 42.23 \(\pm\) 5.52 c \\ \hline \hline \end{tabular} The same letters within the analysed parameter indicate no statistical significance for \(p<\) 0.05.  
\end{table} 
Table 3: The influence of apple wine maturation in the presence of wood on colour parameters (CIELAB). ==ERROR: No output for this page==
\begin{table} \
\begin{tabular}{c c c c c c c c c c c c c c c c c c c} \hline \hline \multicolumn{13}{c}{**Model Cips**} \\ \hline  
+++  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c} \hline \hline  & & & & & & & & & & & & & & & & & & & & & & & & & & \\ \cline{2-13}
**Compounds (SUPAC Name)** & & & & & & & & & & & & & & & & & & & & & & & & & & & \\ \cline{2-13}  & & & & & & & & & & & & & & & & & & & & & & & & & & & \\ \hline \multicolumn{13}{c}{Aldehydes [mg/L]} \\ \hline Fourral (furan-Zen-Eendalldehyde) & 815 & 5000 & 13.2 & 14.9 & 14.7 & 17.1 & 86.7 & 22.2 & 15.3 & 109.3 & 46 & 11.3 & 12.1 & 18.5 & 11.8 & **-** \\ \hline Betweenacetaldehyde (\(\Omega\)-phenylacetaldehyde) & 1015 & 5000 & 0.8 & 6.3 & 7.5 & 5.0 & 8.5 & 7.9 & 3.3 & 2.8 & 2.1 & 2.6 & 1.9 & 7.2 & 4.0 & ns \\ \hline Nonanal & 108 & 0.53 & **0.0** & 62.8 & **0.4** & **1226** & 18.2 & 19.3 & 20.5 & 29.4 & 31.2 & 30.4 & 34.2 & 22.4 & **-** \\  & & & & & & & & & & & & & & & & & \\ \hline \multicolumn{13}{c}{Acids [mg/L]} \\ \hline Corpric acid (Decanoic acid) & 1360 & 2200 & 128.2 &  
The highest concentrations of the tested alcohols were detected in wines aged with apple wood chips, but wines with oak chips also contained significant amounts of alcohol that contributed to their aroma. In most wines with apple and oak wood chips, the concentrations of the tested alcohols were highest after using moderately toasted wood chips (Table 4). The concentration of undecanol increased with the degree of burning of wood chips from most tree species, except maple. In this case, its concentration decreased as the degree of burnout increased. Wines aged with chips made from fruit trees (cherry, apple) were found to have relatively higher concentrations of most esters.