## 3 Results and Discussion
### Wine Characterization
#### 3.3.2 Organic Acids  
Figure 2 reports the amounts of organic acids detected in the pomegranate wines, while Table 3 reports the results of ANOVA. Citric acid is reported as the most abundant organic acid in pomegranate juices and wines [20; 22; 23; 24; 25]. The organic acid profile of wines showed the results of the lactic acid bacteria. In fact, malic acid was not detected, despite being the second organic acid in pomegranate juices as regards abundance [25; 26], while lactic acid was found, indicating the occurrence of malolactic fermentation. Malolactic fermentation, in fact, consists of the decarboxylation of malic acid, obtaining lactic acid as final product. Indeed, the two yeasts used are considered as neutral (EC1118) or even positive (Clos) for the development of malolactic bacteria (Table S1). Figure 2: Contents of organic acids of the pomegranate wines from the four cultivar\(\times\)yeast combinations tested. Data are averages \(\pm\) standard deviations of three replicates per combination. The organic acid profile of the wines also included ascorbic acid and another compound that was identified as tartaric acid, based on the retention time of the standard compound. The literature reports contradictory findings regarding the presence of tartaric acid in pomeranate juices and wines. [PERSON] et al. (2017) described tartaric acid formation and decrease during pomeranate winemaking, with a maximum amount of 1.83 g L\({}^{-1}\). [PERSON] et al. (2012) reported tartaric acid amounts in pomeranate varietal wines in the range \(\sim\)0.2-0.6 g L\({}^{-1}\), undergoing minimal variations during winemaking. As regards pomeranate juices, tartaric acid contents reported in literature range from trace levels to 2.83 g L\({}^{-1}\)([PERSON], 2014; [PERSON], 2015; [PERSON], 2016). In this regard, an issue was raised by [PERSON] and [PERSON] (2015), who reported the risk of routine analytical methods to give false positives/negatives. They applied a method based on stable isotope dilution liquid chromatography-tandem mass spectrometry to twelve pomeranate juices and reported tartaric acid at concentrations in the range 1-5 mg L\({}^{-1}\). Higher amounts (67-380 mg L\({}^{-1}\)) were found in four commercial juices but were attributed by the authors to grape juice adulteration. [PERSON] et al. (2016) investigated ten pomeranate semi-dry red wine samples from Wonderful variety, aging for 1 year in oak barrels, and did not detect tartaric acid when applying HPLC-PDA-ESI-MS\({}^{n}\) analysis. In light of such uncertainty, it seems that further investigation is required considering the identification, detection, and concentrations, as well as variability of tartaric acid in pomeranate juices and wines. Significant differences were observed among the organic acid profiles of the pomeranate wines. _Cultivar_ was the most influencing variable. The most relevant difference regarded the content of citric acid was that wines from Jolly Red cv. contained less than 0.8 g L\({}^{-1}\) of citric acid, while wines from Smith cv. contained above 10 g L\({}^{-1}\). Considering that citric acid is characterized by high perceived sourness ([PERSON], 2014), attention should be paid to the observed difference for possible implications on the sensory characteristics of the wines. The contents of succinic acid reported in the acidic profile of pomeranate juices ranges from 0.00 to 1.54 g L\({}^{-1}\)([PERSON], 2014; [PERSON], 2015; [PERSON], 2016). Higher values were found in Smith wines. This could be attributed to cultivar variability, as well as to fermentation. In fact, variations of succinic acid were reported as a consequence of pomeranate winemaking ([PERSON], 2014). The activity of lactic acid bacteria could also have contributed to reach such high amounts of succinic acid, considering that it has been reported as a product of citrate metabolism in lactic acid bacteria ([PERSON], 2014). The levels of acetic acid were below critical thresholds (the maximum admitted level, according to OIV, is 1.2 g L\({}^{-1}\)) ([PERSON], 2014).