## 3 Results  
### Comparison of the Nitrogen Compound Profiles of the Base Wine and Wines with Yeast Strains  
First, some differences between the two strains should be noted, such as that fermentation was faster in N62 (27 days to reach three atmospheres compared to 52 days in G1), growth was higher in N62 (46 \(\times\) 10\({}^{6}\) cells/mL versus 21 \(\times\) 10\({}^{6}\) cells/mL in G1), and the cell viability was 4 \(\times\) 10\({}^{6}\) cells/mL versus 0.7 \(\times\) 10\({}^{6}\) cells/mL in the G1 strain.  
The nitrogen compounds--13 amino acids, two biogenic amines, and ammonium chloride--were identified and quantified in the samples of base wine (BW) and wines inoculated with the two yeast strains halfway through the second fermentation in a closed bottle in three atmospheres (The results are provided in the Supplementary Materials Table S1). Quantitative and qualitative differences in the nitrogen compounds have been found between the base wine and the inoculated wines, when compared. Glycine and L-norleucine are only found in wine inoculated with strain N62. L-value was identified in this wine and in the base wine, finally, L-arginine was only identified in the wine inoculated with strain G1 and in the base wine.  
PCA was conducted to objectively assess the analysis of nitrogen metabolism. This is a statistical treatment in which variance is maximized and dimensionality is reduced (Figure 1a). This has been constructed from the matrix of the quantification data of nitrogenous compounds in different conditions. The results indicate a clear differentiation of the wines according to the PC1 and PC2 axes, and 96.90% of the total variance is explained in the three wines tested. Figure 1b, using a PCA biplot with the values of PC1 and PC2 as axes, shows that the nitrogenous compounds L-proline, L-lysine, and L-aspartic acid stood out in the base wine, and that ammonium ion, L-norleucine, glycine, and L-alanine stood out in the wine with strain N62, while the amino acids L-ornithine and L-valine decreased significantly in the wine inoculated with strain G1.  
Figure 2 presents a heat map of the quantification data of the normalized nitrogen compounds of the three different wines. This graph illustrates how the triplicates of each sample are more similar to each other than to the rest of the samples. The data that have been obtained are consistent with what was previously shown. In the wine with strain G1, a quantification peak is detected for the amino acid L-arginine. In the base wine, high quantification of the amino acids L-lysine, L-aspartic acid, and L-proline is observed.  
Figure 3 illustrates the nitrogenous compounds that were found in all the replicates of the three samples. These were subjected to one-way analysis of variance (ANOVA) using the homogeneity of variance test, with a \(q\)-value < 0.05 and a log fold change (LFC). Figure 3a compares the nitrogenous compounds of the base wine and the wine made with the G1 strain. All of them showed significant differences; ammonium chloride and L-arginine are the most synthesized nitrogen compounds in the wine inoculated with the G1 strain, and in the rest, there was a higher concentration in the base wine sample. These data suggest that the G1 strain has consumed most of the nitrogen compounds. Figure 3b compares the nitrogen compounds of the base wine and the wine made with the N62 strain; all of them showed significant differences except one. L-lysine and L-proline were detected with higher concentrations in the base wine, and the rest were synthesized in the wine with strain N62. In this case, these findings may indicate that the wine with the N62 strain produced most of the nitrogenous compounds. Figure 3c compares the nitrogen compounds in the wine made with strain G1 and the wine made with strain N62. All showed significant differences, except for two. All of them were found to have increased, with a higher concentration in the elaborated wine with strain N62, which could indicate that this wine produced more nitrogen compounds than the other.