Terroir e Glera: Indagini geochimiche per la definizione dei marker geografici

During the last twenty-years, the increasing demand of Prosecco in the international commerce has required more control in order to avoid falsification and incorrect use of denomination labels. The geographical indication is based on the relationship between the characteristic of the wine and the concept of Terroir. The Terroir, indeed, describes a particular grape variety with specific organoleptic characteristics of the wine, linked to a precise climate area, a geologic setting and a particular wine district or wine region. Considering that, the main purpose of this study is to determine the correspondence among geo-lithological features of the area, geochemistry of vineyard soil and chemical composition of grape (juice and solid residue). This research led on to identify the characteristic territorial markers of Glera cultivar. The analysed vineyards belong to ten distinct wineries, which are located in Veneto-Friuli Region alluvial plain and included in DOC (Controlled Designation of Origin) area of Prosecco wine. The detection of major and trace elements contents in soil was carried out by means of XRF (X-Ray Fluorescence spectroscopy), whereas the grape samples were analysed by using ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Moreover, the heavy metal content in soil, grape and in wine was determined to evaluate a possible human activity, such as the use of fertilizer and pesticide. For each vineyard, in addition, the assimilation coefficient was calculated in order to assess the uptake of minerals in the grape (juice and solid residue) and in the wine, as fingerprints of their own specific content in soil. Through geochemical analysis and statistical approaches (LDA, PCA), the vineyard soils were discriminated according to the geo-lithological characteristic of the area and the trace elements were individuated in grape. Finally, the results of this research are useful to identified the correct relationship between the winery district and the Glera cultivar, demonstrating as some trace and ultra-trace elements could be considered as possible marker for geographical origin.