# Effect of Ultrasound on Fermentation of Thick Molasses Worts by Distiller's Yeast
## 3 Results and Discussion
### Wort Analysis
#### 3.2.1 The Influence of Ultrasound Treatment on Sugar Utilisation
The results of sugar assimilation during the fermentation of word at 24 \({}^{\circ}\)Blg confirmed that our plan to add this word density to the tests was the correct one, even though it differed by only 2 \({}^{\circ}\)Blg from the 22 \({}^{\circ}\)Blg word. From preliminary tests, we knew that somewhere between 22 \({}^{\circ}\)Blg and 24 \({}^{\circ}\)Blg is the limit beyond which there is a visible inhibitory effect of the word density on the fermentation process. The process itself may require more time than the 72 h we assumed. The lowest level of glucose and fructose assimilation was observed for the control sample with TD yeast (glucose 58.05% \(\pm\) 2.46; fructose 24.45% \(\pm\) 0.42), and the best utilisation of glucose was observed for ER u75 (81.57%\(\pm\) 1.08) and fructose for TD u75 (72.58% \(\pm\) 2.54). The effect of sonification is evident for this word density; for both strains, a statistically significant increase in sugar utilisation (\(p<0.05\)) was observed in the sonicated samples compared to the control samples (without sonication). In the case of TD yeast, a statistically significant (\(p<0.05\)) increase in sugar utilisation was also observed depending on the amplitude of the generated ultrasound (66.91% \(\pm\) 2.94 glucose and 37.37% \(\pm\) 1.14 fructose for the TD u50 sample and 78.30% \(\pm\) 2.51 glucose and 72.58% \(\pm\) 2.54 for the TD u75 sample). The assimilation results we obtained are consistent with those obtained by [PERSON] and co-authors [44], who, during the fermentation of mash from thick sugar beet juice by Ethanol Red, achieved a 96.5% reduction of sugars present in the medium over 96 h of word conversion, containing 250 g/L of extract. [PERSON] et al. [56] reported a reduction of up to 93% during the fermentation of word containing 300 g/L of sugars. In the case of an increase in the initial density of the word, the utilisation of sugars decreased, which we observed in our experiments. [PERSON] et al. [48] observed an increase in glucose assimilation of up to 53% during a 36-h fermentation process when using ultrasound on the _Saccharomyces cerevisiae_ SCZ40 strain. 2.2 The Influence of Ultrasound Treatment During Fermentation on Selected Acids and Glycerol Concentrations  
The following table (Table 6) shows concentrations of succinic, acetic, and lactic acids and glycerol in words after 72 h of fermentation. Glycerol, lactic acid, acetic acid, and succinic acid are reported to be significant byproducts during alcoholic fermentation [57] and so were found in analysed samples Table 6). The observed concentration ranges of these acids correspond to the data presented in the literature [58; 59; 60; 61]. Analysis of the results of the content of selected organic acids and glycerol after fermentation of molasses word with a density of 18-24 \({}^{\circ}\)Blg showed that with an increase in the initial density of the word, a statistically significant (\(p<0.05\)) increase in lactic acid concentration was observed for most samples of corresponding samples fermented by the yeast in question, using the same sonication conditions. The concentration of this acid for 18 \({}^{\circ}\)Blg, 22 \({}^{\circ}\)Blg, and 24 \({}^{\circ}\)Blg word was, respectively, for ER yeast without sonication, 2.03 \(\pm\) 0.08 g/L, 3.03 \(\pm\) 0.03 g/L, and 3.56 \(\pm\) 0.13 g/L. Similarly, for the sample fermented by ER yeast, ultrasonicated at 50% amplitude, the following increase was observed with increasing word density: 2.12 \(\pm\) 0.06 g/L, 2.75 \(\pm\) 0.10 g/L, and 3.46 \(\pm\) 0.12 g/L. A similar trend was observed for samples fermented by the TD strain and ultrasonicated at an amplitude of 75%. Such clear trends could not be observed in the case of the other acids and glycerol. Organic acids can originate from the raw material (beet molasses) or can be formed during the fermentation process by yeast. Additionally, contaminating microflora potentially present in the molasses can grow after dilution, competing with the yeast.