# Impact of Selected Yeast Strains on Quality Parameters of Obtained Sauerkraut
## 3 Results and Discussion
### Principal Component Analysis (PCA)
However, this does not change the fact that when microaerobic conditions are created, there is strong proliferation and a significant impact on the parameters of sauerkraut [4]. The discussed group of yeasts also included cultures that increased the decomposition of glucosinolates (probably, these compounds were partially metabolised as a carbon source), which resulted in an increase in the number of components produced by such decomposition [35; 36]. The negative effects of this phenomenon are a reduction in the number of components with health-promoting activity and, on the other hand, the formation of a large number of compounds with an unpleasant, sulphurous aroma. On the right side, close to the control sample, there were cabbages fermented with _Rh. mucilginosa_ Rm8 yeast, which means that the qualitative compositions of these samples were similar. _Rhodotorula_ yeasts are strictly aerobic organisms; therefore, their growth during sauerkraut fermentation is limited to the initial stages or to specific conditions when oxygen is available [51]. The two _Rh. mucilginosa_ strains analysed behaved differently, with the Rm26 culture significantly reducing the levels of the compounds analysed in sauerkraut, while Rm8 had no such negative effect (Tables 2-5). We observed similar large differences between these strains when analysing their presence during the fermentation of sauerkraut [4]. The Rm26 culture was present throughout the fermentation, regardless of the presence or absence of oxygen. The Rm8 strain developed more slowly, and its growth depended on aerobic conditions. On the right, below the control sample, there are samples of sauerkraut fermented with the yeast _D. hansenii_. They formed a homogeneous group, demonstrating the high similarity of the influence of these cultures on the fermentation process and the components produced. The _D. hansenii_ yeast often accompanies lactic acid bacteria (LAB) during the spontaneous fermentation of various foods [10]. In previous studies, we detected it throughout the fermentation of sauerkraut, regardless of the variety or conditions used during the process [4; 5]. Current research confirms that this yeast is an important microorganism for obtaining good-quality sauerkraut. The products obtained with its participation were characterised by an increased level of lactic acid, but also by a positive aroma, which resulted in high scores in the sensory analysis. The cabbage obtained with _Cl. hustantiae_ Cl6 is located furthest on the right. These tests were characterised by a very large number of analysed volatile compounds such as alcohols, esters and lactones. We first detected the yeast _Clavispora lustimiae_ in the fermentation process of sauerkraut [5], and at the same time we found that its growth was promoted by anaerobic conditions [4]. In the research described, we confirmed that this microorganism develops well during fermentation and does not disturb the course of lactic acid fermentation. However, it produces very large amounts of volatile compounds that modify the aroma of sauerkraut by introducing a large amount of floral notes. Unfortunately, the aroma obtained with it received a lower score in the overall evaluation due to its deviation from the typical aroma.