## 3 Results and Discussion
### Tartaric Stability  
Tartaric acid is one of the main organic acids present in grapes, must and wine [40]. However, its supersaturated presence can lead to one of the most common physico-chemical instability problems in enology: tartrate precipitation [44]. This leads to the appearance of  
Figure 7: Results of Volatile Acidity 3 months after the end of AF (Stage 4) (n = 9). Statistically significant differences (\(p<0.05\)) are indicated by different letters assigned to the means. crystal sediments, not only during alcoholic fermentation but also over the course of the aging and storage period [44; 45]. While being a natural phenomenon, its appearance is considered a quality fault and is mainly observed in white wines, considering the usual lower temperatures of conservation [44]. Therefore, the assessment of the tartaric stability of wines and possible posterior stabilization treatment are strongly advised. The most common stabilization method relies on temperature effects (cold stabilization), ion removal (electrodialysis and ion-exchange resins) or introducing stabilization additives, such as mannoproteins, metatartaric acid and carboxymethyl cellulose (CMC) [65; 66; 67]. These treatments represent considerable costs for the wineries. Tartaric acid (H2T) dissociates and reacts with Ca\({}^{2+}\), forming precipitates of Calcium Tartrate (CaT), or with K\({}^{+}\), creating potassium hydrogen tartrate (KHT) [67]. The crystallization kinetics can be affected by temperature, wine composition, colloidal matter, pH, alcohol content, KHT initial supersaturation and, of course, the concentration of cations, such as Ca\({}^{2+}\) and K\({}^{+}\)[44; 67; 68]. Considering that potassium might be stored in the vacuole of berries' skin cells [69], the use of processes that may affect the structural integrity of lipidic membranes, such as PEF and enzymes [70], can promote the extraction of cations and alter the dynamic of this natural phenomenon. Thus, it was decided that tartaric stability would be assessed 6 months after vinification, allowing to a better understanding of the possible effects of each biotechnology in this matter. The obtained results are presented in Table 6 and Figure 8. \begin{table}
\begin{tabular}{c c c} \hline  & \(\Delta\)**Conductivity (\(\Delta\chi\)\%)** & \(\Delta\)**Conductivity (\(\Delta\chi\)\%)** \\ \hline ARC1 & \(9.33\pm 0.68\) & \\ \hline ARC2 & \(7.37\pm 0.89\) & \(8.48\pm 1.23\) \\ \hline ARC3 & \(8.73\pm 1.33\) & \\ \hline ARE1 & \(5.56\pm 0.63\) & \\ \hline ARE2 & \(4.81\pm 1.10\) & \(5.51\pm 0.87\) \\ \hline ARE3 & \(6.16\pm 0.15\) & \\ \hline ARPEF1 & \(4.94\pm 0.67\) & \\ \hline ARPEF2 & \(2.85\pm 0.18\) & \(3.01\pm 1.74\) \\ \hline ARPEF3 & \(1.24\pm 1.17\) & \\ \hline \end{tabular} Results presented in \(\Delta\)uS/cm. n = 3.  
\end{table} 
Table 6: _Mini-Contact_ test Results. Figure 8: Tartaric Stability assessed 6 months after the end of AF (Stage 4) (n = 9). Statistically significant differences (\(p<0.05\)) are indicated by different letters assigned to the means. Statistical analysis was performed using one-way ANOVA, which demonstrated not only significative differences between all treatments but also a large effect size of approximately 78.5% (F(2, 24) = 26.675, \(p\) < 0.001, \(\eta^{2}\) = 0.785). The obtained results prove the possibility of using both PEF and enzymes to contribute to a higher level of natural stability of white wines. However, considering that only PEF-treated wines present a drop in conductivity of \(\Delta\chi\%>\) 5%, as stipulated by [PERSON] et al., (2016), only this group is considered stable from the tartaric point of view [(43)]. A comprehensive review of the literature revealed, to the best of our knowledge, no published articles regarding the effect of PEF application on the tartaric stability of wines.