# New Isolated Autochthonous Strains of _S. cerevisiae_ for
## 3 Results and Discussion
### Determination of Wine Fermentation By-Products
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Strain** & **Acetaldehyde** & **Ethyl Acetate** & **Methanol** & **1-Propanol** & **Iso-Butanol** & **Amyl Alcohols** \\
**Symbol** & **[mg/100 mL]** & **[mg/100 mL]** & **[mg/100 mL]** & **[mg/100 mL]** & **[mg/100 mL]** & **[mg/100 mL]** \\ \hline
1\_NCS & 3.536 \(\pm\) 0.413 \({}^{\text{ac}}\) & 1.913 \(\pm\) 0.230 \({}^{\text{ad}}\) & 4.526 \(\pm\) 0.533 \({}^{\text{ab}}\) & 0.622 \(\pm\) 0.072 \({}^{\text{bnde}}\) & 5.878 \(\pm\) 0.704 \({}^{\text{ad}}\) & 32.935 \(\pm\) 3.894 \({}^{\text{d}}\) \\ \hline
2\_NCS & 3.025 \(\pm\) 0.135 \({}^{\text{ad}}\) & 1.154 \(\pm\) 0.050 \({}^{\text{ad}}\) & 3.255 \(\pm\) 0.151 \({}^{\text{a}}\) & 0.422 \(\pm\) 0.016 \({}^{\text{a}}\) & 3.843 \(\pm\) 0.167 \({}^{\text{bc}}\) & 21.770 \(\pm\) 0.961 \({}^{\text{ad}}\) \\ \hline
3\_NCS & 3.885 \(\pm\) 0.155 \({}^{\text{ac}}\) & 1.789 \(\pm\) 0.074 \({}^{\text{ad}}\) & 4.646 \(\pm\) 0.223 \({}^{\text{b}}\) & 0.643 \(\pm\) 0.017 \({}^{\text{ad}}\) & 5.381 \(\pm\) 0.212 \({}^{\text{ad}}\) & 29.925 \(\pm\) 1.178 \({}^{\text{ad}}\) \\ \hline
4\_NCS & 3.957 \(\pm\) 0.077 \({}^{\text{ad}  
The concentration of 1-propanol, the third studied in this work fused alcohols varied from 0.422 to 0.682 mg/100 mL and from 1.409 to 6.028 mg/100 mL for the white and red wines, respectively. In general, the concentrations of this higher alcohol were higher for red wines than for white wines. The highest amounts were found in wines fermented with native yeast strain 6_NCS and 4_NCS for red and white wines, respectively. Whereas the lowest were determined for 4_CS and 2_NCS for red and white, respectively. The obtained concentrations of 1-propanol were considerably lower than those previously reported 1.32 mg/100 mL and 4.5-6.0 mg/100 mL for white and red wines, respectively [1; 94]. Moreover, in the case of white wines, they were even lower than the reported typical ranges of propanol concentrations in wine: 0.9 to 6.8 mg/100 mL [95]. The obtained concentrations of methanol were considerably higher and in wider range in examined red wines (7.33-20.451 mg/100 mL) compared to the white wines (3.255-4.986 mg/100 mL). The typical concentration of methanol determined in wine is approximately 3.0-3.5 mg/100 mL [98]. Methanol is a product of the enzymatic hydrolysis of pectin, and is potentially harmful if consumed in excessive amounts. According to the International Organization of Vine and Wine (OIV) the acceptable limit of methanol is 40.0 mg/100 mL for red wines and 25.0 mg/100 mL for white wines and roses [99]. The concentrations of methanol in wines obtained in this study, despite being higher than usually found in wines, did not exceed the permissible limits. The concentrations of ethyl acetate in the analyzed wines fell within a narrower range compared to the other volatile by-products of yeast alcoholic fermentation. The obtained range for the white wines was from 0.908 to 2.60 mg/mL and for the mostly red wines from 0.575 to 1.897 mg/100 mL. Among the red wines, samples fermented with 9_NCS, 6_NCS, and 6_CS had a significantly higher amount of ethyl acetate i.e., 4.045 mg/100 mL, 5.719 mg/100 mL, and 6.858 mg/100 mL, respectively. Ethyl acetate (fruity, solvent-like) is the most common ester in wines synthesized by strains of _S. cerevisiae_ species. Based on the previous reports, it has been stated that small amounts of ethyl acetate (5.0-8.0 mg/100 mL) positively contribute to the quality of the wine, however in excessive amounts can cause foreign flavors. Its content in young wines ranges from 2.5 to 30 mg/100 mL [100]. The previously reported concentrations of ethyl acetate determined for Polish Seyval blame and Regent wines were 4.72 mg/100 mL and 2.2-4.7 mg/100 mL, respectively. The concentrations obtained herein were mostly lower except for red wines fermented with 6_NCS and 6_CS. Taking into account the determined concentrations of higher alcohols and esters an interesting observation was made.