# Characterization of Freisa Wines from Piedmont (Italy) by Aroma and Element Profile
## 3 Results and Discussion
### Major, Minor and Trace Elements
From the box plots (Figure 3b), it is possible to evidence that CTF samples showed the highest concentrations for Sr while MF samples showed the lowest concentrations for Zn. It is also interesting to observe the opposite trend shown for Mn and Cr distribution among the Freisa wines collected in the different Piedmont sites. In particular, the CTF samples were characterized by the highest mean concentration for Cr and by the lowest concentrations for Mn, while FA samples were characterized by high concentrations for Mn and low concentrations for Cr. It should be kept in mind that Mn, as Cu and Fe, forms stable complexes with amino acids, polyphenols, melanoids and other chelating ligands. This association is an important natural anti-oxidative mechanism that decreases the rate of formation of reactive oxygen species responsible for reactions causing staleness and spoilage of wine [37]. In taking this into account, it is possible to hypothesize that FA samples containing the highest mean concentrations for Mn and Cu also likely have a higher anti-oxidative capacity. Moreover, as the content of Cu and Fe does not exceed the concentration of 1 mg L\({}^{-1}\) and 7 mg L\({}^{-1}\), respectively, it is possible to declare that Freisa wines do not give unpleasant, as stringent cupric and ferric tastes, often present when the Cu and Fe content in the wine is higher than the concentrations indicated above [35]. Figure 3: Oxplot of the elements determined in Freisa wine samples from Asti (FA), Chieri (FC), Colli Tortonesi (CTF), Langhe (LF) and Monferrato (MF) sites (**a**) Ca, Fe, Mg, Na, P, and Rb; (**b**) Al, Ba, Cr, Cu, Mn, Ni, Sr, Ti, and Zn. In all samples, the concentrations of Zn and Cu, considered of special interest due to their toxicity in case of excess, were much lower than the legal threshold limit values established for the Italian wines by the Italian Republic (DM 10/08/2017), namely 5 mg L\({}^{-1}\) for Zn and 1 mg L\({}^{-1}\) for Cu [38]. Comparing element contents in Freisa wines and in other Italian red wines, it is evident that Cr and Ni concentrations in our wines were much higher. In particular, Cr concentration is approximately 4 to 10 times higher in Freisa wines than that reported in the other Italian wines. The higher content of these elements is probably due to a relevant natural contribution for chromium and nickel from soils: indeed, Piedmont plains are constituted by sediments that partly derive from serpentinite areas; this, as already reported by other researchers [39; 40; 41], causes high background levels of Ni and Cr in soils. It is possible to conclude that the relatively high content of these metals is attributable to the characteristics of the soil on which the vineyards are grown, and they can be considered of natural origin and possible markers for the Freisa wine. Moreover, Freisa wines had a lower content of Ba, Mg, and Zn than the other red Italian wines considered. In comparison with red Italian wines from Southern areas and Sicily, the Freisa wines showed lower Al, Ca, Mn, and Sr concentrations. Finally, the Cu concentration in Freisa wines was higher than in the wines produced in Campania, Tuscany and Veneto but similar to that present in Sicilian wines. Nevertheless, the concentration of most elements in Freisa wines fell in the range of Italian red wines; this happened mainly for Fe, Na, P, Rb, and Ti and partially for the other elements investigated.