CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Influence of Grape Variety on the Absorption of Minerals from Soil. Probable Consequences to Wine Traceability. A Case Study: Province of San Juan (Argentina).
Autor/es:
WUNDERLIN, D. A.; FABANI, M.P.; VAZQUEZ, F.; DÍAZ, M. P.; RUBINSTEIN, H.R.
Lugar:
Creta. Grecia
Reunión:
Congreso; III° Meeting of TRACE Project EU.; 2007
Institución organizadora:
TRACE Project EU. Universidad de Atenas.
Resumen:
Wine is a complex product widely consumed worldwide. The huge diversity of production areas generates the need of establishing the provenance of this product, considering that the properties of wines are influenced by many factors: their history, grape varieties, soil and climate, yeast, oenological practices, transport and storage. The regional name of the wine plays an important role, because it allows developing a particular standard of quality, which is appreciated by consumers. Controlled Denomination of Origin (DOC) has been established in Argentina looking to guarantee the origin and quality of its wines and also to prevent frauds. We evaluated several minerals in wines, grape juices and soils from Valley of Tulum (Province of San Juan-Argentina), aiming to assess the chemical bases necessary to obtain DOC for wines produced in this region. Our main goal was to verify differences between mineral profiles of different wine varieties arising from similar soils, thus evaluating changes in the absorption of minerals by different types of grapes. Samples of wine (n= 18), grape juice (n= 16) and soil (n= 39) were provided by the cellar Augusto Pulenta, Finca - "Doña Filomena" (San Juan, Argentina). Wine samples correspond to 100% pure varieties: Cabernet Sauvignon, Bonarda, Malbec and Syrah. The concentration of 11 metals (K-Na-Ca-Mg-Fe-Mn-Zn-Cu-Co-Ni-Cr) were determined by Atomic Absorption Spectroscopy (AAS). Wine samples were analyzed without previous treatment adding 1% HNO3. Soil samples were treated with 20 mL aqua regia (HCl/HNO3 3:1) per gram. Data were analyzed by Linear Discriminant Analysis (LDA) to establish differences among samples. Canonical discriminant functions were obtained after applying a stepwise variable selection method. LDA was also applied to soil data set. These functions enabled 76 % right classification of soils, using five out of eleven parameters. Thus, K, Mg, Zn, Mn and Ni could be a valuable data set to distinguish between the five parcels in which different varietals grew. Similarly, for grape juices and wines data sets, LDA allowed 83% and 89% right discrimination between the five varietals studied respectively, using the same variables selected for soils. Box plots of these selected variables evidence that Mg has almost the same profile in soils, juices and wines, while Mn profiles are similar in juices and wines but different from the corresponding to soils. The remainder three variables (K, Zn and Ni) present different patterns between soils, juices and wines. So far, it seems that the concentration of Mg in wine and grape juice is closely related to its amount in soil. On the other hand, the pattern for Mn shows that plant metabolism changes its relative amounts from soil to juice, but the wine retain the same trend that juices (not influenced by oenological process). Finally the relative levels of K, Zn and Ni in wines did not present correspondence with the precursor juice nor with the corresponding soil. The differences observed in mineral profile of soils, grape juice and wine point out the need of considering plant physiology to assess reliable markers for wine traceability.