Profile of phenolic compounds in Cabernet Franc berries and wines in different Geographical Indications of Mendoza, Argentina

MUÑOZ, FLAVIO; RASSE, MANUEL; URVIETA, ROY; BUSCEMA, F.; BOTTINI, R.; FONTANA, A.; BERLI, F.

Punta del Este

Congreso; 41st World Congress of Vine and Wine; 2018

The vineyards of Mendoza are geographically distributed in five departments that belong to the different productive oases. Inside of these, there are Geographical Indications (GIs) that allow identifying the products origin with different reputation, quality and characteristics associated with each locality. For example, the Uco Valley is the place with high altitude vineyards of the province (being located on the foothills of the Andes mountains), and it has 14 different IGs. In Argentina, the Cabernet Franc cultivar is found in all wine producing provinces (929 ha), representing about 0.4 % of the total vineyards of the country of which 685 ha are in Mendoza (INV, 2016). In Mendoza, the vineyards of Cabernet Franc are concentrated in the Uco Valley (45%) and Luján de Cuyo (33%) (INV, Cabernet Franc Variety Report, 2017). Cabernet Franc has been growing, so it changed from a variety used for blends wines to be vinified as a medium-high quality wine, mainly because it has a potential to produce high-added-value wines with distinctive characteristics. The particularities of the vine and wines depend on the "terroir". In the simplest sense, this concept refers to the effects of vegetative material (genotype) combined with the environmental factors and the crop management conditions. Likewise, the significance of quality integrates several aspects, but for the production of red wines, they correlate with high contents of phenolic compounds.The present study aimed to characterize the profiles and concentration of phenolic compounds of Cabernet Franc cv. grapes and wines from vineyards located in different GIs of the Uco Valley and Luján de Cuyo. Representative parcels from different GIs (Gualtallary, Eugenio Bustos, Paraje Altamira and Agrelo) were selected. Grapes at commercial maturity (24Brix) were harvested and wines were made in triplicate under standardized conditions in 800 liters vessels. In order to evaluate the effect of the cultivation site, an experimental system where the greatest variations were given by the environmental factors such as temperature, altitude, radiation, humidity was designed.The phenolic compounds of berries and wines were determined by liquid chromatography with diode array detector (HPLC-DAD). The results revealed that samples of different GIs have different chemical composition, and that the levels of many compounds are correlated with variables such as the altitude and thermal amplitude at which the vineyards are located. The concentration of anthocyanins and total polyphenols was higher at GI Gualtallary. This fact could be related to the higher UV-B exposure of this vineyard (1350 m a.s.l.) and its lower mean temperature. This work shows that the studied GIs could be differentiated by the phenolic composition of their grapes and wines by applying different classification models. The purpose is adding knowledge related to the influence of geographical origin on the chemical characteristics of Cabernet Franc wines to potentiate their differentiation and future commercial valuation.