## 3 Results and Discussion
It could be that lower temperatures, kinetic of phenolic compound extraction, and kinetic of fermentation (slower rate of sugar degradation) at the start and lower alcohol content in L wines decrease extraction of gallic acid from grape seeds [20]. Other hypotheses are that already extracted gallic acid during fermentation reacts with alcohols formed by yeasts [57] or is adsorbed by the cell wall [58]. Previously, a selection of _S. cerevisiae_ strains in Plavac Mali wine production had an impact on this HBA with a maximum of S16 strain [23]. Moreover, an increase in S and N wines can be associated with a tannase activity of _S. cerevisiae_ or one of the yeasts from the natural population that can biodegrade hydrolyzable tannins [59]. A decrease in phenolic acids in L wines can lead to a higher sensory quality of those wines, as those are known to contribute to the astringency and bitterness of wine and have a synergetic effect on the perception of astringency [60]. Sequential L fermentation led to a significant decrease in the concentration of eight individual (four individual anthocyanin-3-O-glucoside as follows delphinidin, petunidin, peonidin, malvidin), and acetyl, caffeoyl, and _p_-coumaroyl derivatives of malvidin-3-O-glucose, peonidin-3-O-glucose _p_-coumaroyl and the total sum of anthocyanins. The greatest reduction is seen in the main anthocyanin compound, malvidin-3-O-glucose, the concentration of which in S wines was 85.30 \(\pm\) 2.80 mg/L, and in L wines decreased to 70.32 \(\pm\) 0.69 mg/L. S and N wines differed only in the concentration of delphinidin-3-O-glucose and malvidin-3-O-caffeoyl-glucose, both of which reached a maximal value in N wines. Although a decrease in anthocyanins in L wines could be associated with a stronger adsorption capacity of the yeast cell wall [61]. Previously, higher cyanidin-3-O-(6\"-\(p\)-coumaroylglucoside), petunidin-3-O-(6\"-\(p\)-coumaroylglucoside), and malvidin-3-O-(6\"-\(p\)-coumaroylglucoside) content in sequential fermentations is associated to a lower anthocyanin absorption by _L. thermotolerans_ strain [19]. More probably, those anthocyanins react with pyruvate acid and acetaldehyde and form more stable compounds such as vitisin, acetylylitisin, and _p_-coumaroylvitisin A and B [61]. Another explanation could be that certain differences in wine matrix are partially caused by an increase in total acidity and a decrease in pH initiate reactions between hydroxycinnamic acids and anthocyanins and the formation of vinylphenolic pyraonathocyanins without the enzymatic support of yeast [62]. Among flavonoids, the greatest reduction is seen in sequential L fermentations, with a significant decrease in miricetin-3-O-glucose, quercetin-3-O-glucoside, kaempfer-3-glucuronide, and total flavonoids. The S and N wines differed significantly only in 3-O-glucuronides of miricetine and quercetin, with the highest concentrations in N and S wines, respectively. Flavonols react with anthocyanins or each other, the result of which are anthocyanin-flavanol, flavanol-anthocyanin, and flavanol-flavanol adducts. The main yeast-derived byproducts that participate in those processes are acetaldehyde and pyruvate acid. It could be that larger differences between L and S than between N and S are the result of the interrelationships between these two yeasts. _L. thermotolerans_ is known as the strain that generally produces lower concentrations of acetaldehyde and pyruvate acid, but this is highly influenced by a strain and used inoculation modalities (sequential or co-inoculation) [11]. Sequential L fermentation led to a significant decrease in catechin, epicatechin, proanthocyanidin dimers B1, B2, B3, B4, and the total sum of flavan-3-ols in comparison to S and N wines. Those flavan-3-ols, especially catechin and epigallocatechin, are indicators of seed and skin extraction in wine [63]. There are scarce results in the literature about the impact of yeasts on flavan-3-ol monomer and dimer wine profile.