# How Different Fermentation Type Affects Volatile Composition of Plum Jerkums
## 3 Results and Discussion  
### Chemical Composition of Fresh Plum Musts and Jerkums  
Musts obtained from Wegierka Dabrowicka and Stanley demonstrated the highest concentration of total extract and total sugars which constituted about 80% of the total extract. However, in comparison to other cited studies, concentrations of total sugars in our samples were slightly low and ranged from 113.2 (Wegierka Zwykla) to 123.8 g/L (Wegierka Dabrowicka) (Table 1), whereas in other studies it reached 153.6 g/L [14] or 127.5 g/L [4], respectively. Sugar content in plum influences consumer perception of maturity of consumed fruits and its concentration depends on the fruit cultivar, climatic conditions, and harvesting time [4; 15]. Total extract of analyzed samples decreased after fermentation, which was caused by intense consumption of sugars during that process and high fermentation efficiency ranging from 66.6 to 99.3% (Table 2). The highest fermentation efficiency and concentration of ethanol (more than 7% vol.) was determined in musts f \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Plum** & **Total** & **Total** & **Reducing** & **Sugars** & **Sugars-Free** & **Titradable** & **Citic** & **Malic** & **Succin** & **Free Amino** \\
**Culturas** & **Extract** & **Sugars** & **Sugars** & **Extract** & **Acidity** & **Acid** & **Acid** & **Acid** & **Acid** & **Nitrogen** \\ \hline  & & & & & & & & & [mg/L] & \\ \hline Wegierka & 146.0 \({}^{\circ}\) & 113.2 \({}^{\text{b}}\) & 42.6 \({}^{\text{ab}}\) & 51.4 \({}^{\text{a}}\) & 26.7 \({}^{\text{b}}\) & 9.06 \({}^{\text{b}}\) & 1.12 \({}^{\text{b}}\) & 6.13 \({}^{\text{ab}}\) & 0.56 \({}^{\text{b}}\) & 119.6 \({}^{\text{c}}\) \\ Zwykla & (\(\pm\)2.0) & (\(\pm\)4.3) & (\(\pm\)2.3) & (\(\pm\)2.0) & (\(\pm\)4.2) & (\(\pm\)0.39) & (\(\pm\)0.07) & (\(\pm\)0.24) & (\(\pm\)0.11) & (\(\pm\)11.4) \\ \[PERSON] & 155.7 \({}^{\text{b}}\) & 123.8 \({}^{\text{a}}\) & 45.9 \({}^{\text{a}}\) & 47.9 \({}^{\text{ab}}\) & 37.8 \({}^{\text{a}}\) & 12.22 \({}^{\text{a}}\) & 1.00 \({}^{\text{b}}\) & 6.41 \({}^{\text{ab}}\) & 1.13 \({}^{\text{a}}\) & 135.6 \({}^{\text{bc}}\) \\ Dabrowicka & (\(\pm\)1.5) & (\(\pm\)5.7) & (\(\pm\)2.6) & (\(\pm\)2.9) & (\(\pm\)4.2) & (\(\pm\)0.23) & (\(\pm\)0.04) & (\(\pm\)0.58) & (\(\pm\)0.14) & (\(\pm\)4.6) \\ \hline Stanley & 161.7 \({}^{\text{ab}}\) & 121.4 \({}^{\text{a}}\) & 40.3 \({}^{\text{b}}\) & 56.7 \({}^{\text{a}}\) & 37.7 \({}^{\text{a}}\) & 9.81 \({}^{\text{b}}\) & 1.50 \({}^{\text{a}}\) & 7.26 \({}^{\text{a}}\) & 0.82 \({}^{\text{a}}\) & 156.4 \({}^{\text{b}}\) \\  & (\(\pm\)6.4) & (\(\pm\)2.6) & (\(\pm\)4.3) & (\(\pm\)2.2) & (\(\pm\)9.0) & (\(\pm\)0.47) & (\(\pm\)0.17) & (\(\pm\)0.29) & (\(\pm\)0.24) & (\(\pm\)6.6) \\ \hline C\(\circ\)canska & 151.0 \({}^{\text{c}}\) & 119.4 \({}^{\text{ab}}\) & 32.1 \({}^{\text{b}}\) & 44.5 \({}^{\text{b}}\) & 41.4 \({}^{\text{a}}\) & 11.90 \({}^{\text{a}}\) & 1.04 \({}^{\text{b}}\) & 6.56 \({}^{\text{ab}}\) & 0.98 \({}^{\text{a}}\) & 212.1 \({}^{\text{a}}\) \\ Lepotica & (\(\pm\)1.0) & (\(\pm\)2.6) & (\(\pm\)2.0) & (\(\pm\)1.6) & (\(\pm\)2.5) & (\(\pm\)0.53) & (\(\pm\)0.12) & (\(\pm\)0.33) & (\(\pm\)0.05) & (\(\pm\)5.1) \\ \hline Significance & ** & ** & ** & ** & ** & ** & ** & ** & ** \\ \hline \multicolumn{10}{c}{Values with different superscript roman letters (a–c) in the same column indicate statistically significant differences at \(p<0.05\); \(n=5\); 0.001 **; 0.01 **.} \\ \end{tabular}
\end{table} 
Table 1: Chemical composition of fresh plum musts. (_S. cerevisiae_) or with _S. cerevisiae_ S1, while lowest efficiency was shown for musts fermented spontaneously. According to the manufacturer's specification, Ethanol RED is more resistant to ethanol concentration exceeding 18% vol. and provides higher fermentation efficiency than many other yeast strains [16]. This would explain the results described in the current paper. In the current study, it has also been demonstrated that microorganisms used for fermentation and plum cultivar affected the rate of fermentation.