PHENOLIC PROFILING OF MALBEC WINES FROM MENDOZA: INFLUENCE OF TERROIR

ROY URVIETA; ARIEL FONTANA; M.S FERNANDO BUSCEMA; RUBEN BOTTINI

Rosario

Simposio; Second Latin American Metabolic Profiling Symposium; 2016

IBR-UNR-CONICET

Malbec is the most cultivated variety in Argentina with 34.559 ha in Mendoza1. In the international market a wide price gap of Malbec wines can be found, and one of the most important factor defining the quality and final prices is the origin of the grapes, also denominated with the name of ?terroir?. The concept of ?terroir? in viticulture refers to a complex interplay of factors, covering the vine and its surrounding environment, highlighting the importance of climate, soils, plant material, and human intervention2. Mendoza´s environmental conditions are highly variable within its territory, from cold areas as Gualtallary in Tupungato, to warmer zones such as the East of the province. Phenolic compounds are products of secondary metabolism present in the vacuoles of berry skins that are extracted during vinification3. The profiling and relative concentration of phenolics can be used as markers of wines origin, thus giving information about the ?terroir?4.The objective of the present study was to investigate the influence of geographical location on phenolic composition of Malbec wines from grapes of 25 parcels distributed in 6 regions of Mendoza, Argentina. Each parcel was selected based on their uniformity and regional representativeness, and the same winemaking technique without oak aging was used. Phenolics, anthocyanins and non-anthocyanins, were analyzed by HPLC-UV after 6 months of bottle aging. Thirty phenolics were characterized and their relative amounts analyzed using chemometrics. Results show that Mendoza´s Malbec wines have phenolic compositions associated to geographic origin. In the so called ?First zone? and ?Uco Valley?, wines from different appellation have similar phenolics profile, while wines of ?East zone? are separated from the other two regions. Discriminating by Department, similar characteristics for San Carlos and Luján de Cuyo were obtained; Tunuyán and Tupungato were fairly similar, while the Departments of Maipú and Rivadavia were clearly differenced. By performing cluster analysis, a wide variability in the phenolics profiles of wines from each zone was observed, where parcels located in the same vineyard are quite different among them, although they may be assimilated to wines from other region. The results suggest that the actual ?terroir? denomination in Mendoza defined as political limits may not be the proper way for classification of wines, since a great influence of climatic and soil characteristics of each parcel were observed.