Discrimination of geographical origin of hop (Humulus lupulus L.) using geochemical elements combined with statistical analysis.

Beer is a popular alcoholic beverage worldwide, traditionally made from water, barley and hop (Humulus lupulus L.) strobili. The strobili contain lupulin glands whose components (mostly bitter acids and polyphenols) confer unique and locally different flavours to beer types. It is therefore relevant for brewers and consumers to precisely know the geographical origin of hop plants used for high-quality beer. Hop plants belonging to the variety Hallertau Perle, grown in two locations, Cavalese and Imèr, of the Trentino Region (Italy) were analysed to establish a direct relationship between the chemical elements detected in soil and in plant parts. Chemical elements were determined by X-ray fluorescence and inductively coupled plasma mass spectrometry in soil, leaf and strobili samples from Cavalese and Imèr. The data from the two areas were compared by a nonparametric test (Mann-Whitney) and multivariate statistics (principal component analysis and partial least squares discriminant analysis). The geochemical characterization and the statistical analyses showed different concentrations of major and trace elements in soil and plant parts from the two areas. A reliable correlation could be established between some elements in soil and strobili samples, that is Nb, Fe, Rb and Zr for Cavalese and Mg, Ni, Zn and Zr for Imèr. These elements could therefore be used as geochemical fingerprints to identify the geographical origin of strobili from the two study areas, an approach useful to verify the origin of hop plants for the production of high-quality beer.

Chemical elements as fingerprints of geographical origin in cultivars of Vitis vinifera L. raised on the same SO4 rootstock.

The uptake of major and trace elements in grapevine (Vitis vinifera L.) can be influenced by soil, climate, geographic origin, and rootstock type. Rootstocks were mainly selected to resist phylloxera and for specific tolerance to lime, mineral uptake, drought, and salinity. The relationship among concentrations of major, trace, and rare earth elements was studied in soil and leaves from two Italian grapevine cultivars, "Cabernet Sauvignon" and "Corvina," employed to produce renowned controlled designation of origin (DOC) wines. The cultivars were raised on the same rootstock SO4 in two different areas of the Veneto Region (Northern Italy). The elements were studied by X-ray fluorescence and inductively coupled plasma mass spectrometry, and data were elaborated by non-parametric tests and multivariate linear discrimination analysis. The related index of bioaccumulation was calculated to define the specific assimilation of the elements from soil to leaves. A statistically significant correspondence between soil and leaf samples was observed for Mg, Sm, V, and Zr. The results allowed to discriminate soil and leaf samples of the two cultivars according to geographical provenance, possibly providing geochemical markers (fingerprints) useful against fraudulent use of DOC wine labels.