Tracing the “terroirs” via the elemental composition of leaves, grapes and derived wines in cv Nebbiolo (Vitis vinifera L.)

Abstract

Thirty-nine samples of leaves and berries from 8 sites and 16 related samples of wines coming from seven sites were analyzed by means of inductively coupled plasma–atomic emission spectroscopy (ICP–AES). Twenty elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Ni, Sb, Si, Sr, Ti, V, Zn, Zr) were analyzed. The aims of this study were to determine whether some elements could be used to trace the origin of grapes and wines and whether rootstock and variety may contribute to the selective uptake of these elements. In addition, to improve the classification by geographical origin, this study evaluated whether the presence of some elements is more dependent on the environment or on the rootstock/variety. Principal component analyses (PCA) were applied to leaf, berry and wine elemental composition to distinguish among the sites. A non-parametric test was used to compare the means of the five plots of leaves and berries for the rootstock and variety mineral composition.A good separation was obtained among the leaf, grape and wine samples with respect to their geographic origin. Ba, Mn, Si, Sr and Ti had the most discriminant power to separate the sites of the Alpine area from the sites characterized by calcareous clay soils of the Langhe area. Rootstock and variety had effects on the selective absorption of several elements in grapes and leaves but the grape mineral content seemed more efficient in discriminating samples than leaf mineral content. Although Ba, Si and Ti absorption showed the influence of rootstock and variety, they played a major role in discriminating the geographical origin of the samples.