Análise cromática de vinhos tintos da variedade Cabernet Sauvignon do Rio Grande do Sul

Abstract

In the Rio Grande do Sul State, grape production is an already consolidated activity of significant socio-economic importance, accounting for about 90% of national production of grapes, wines and derivatives. In this sense, wine is an important product because of the added values transferred to the wineries and grape growers. There are five major wine regions within Rio Grande do Sul: Serra do Nordeste, Campanha, Serra do Sudeste, Central and Campos de Cima da Serra. Cabernet Sauvignon is the State's most important Vitis vinifera variety. The wine of this variety is world famous for its varietal character, intense color, richness in tannins and for its complexity of aroma and bouquet. Color is a key indicator of quality wines. It contributes to achieving the highest ratings and effectively the highest prices, and is directly related to quality of the raw material used. The objective methods of color evaluation are the fastest and, moreover, are replicable and not subject to subjective errors, so are of fundamental importance for the wine industry. The samples of red wines for this study, from the five wine regions of Rio Grande do Sul, were obtained in collaboration with the Instituto Brasileiro do Vinho (IBRAVIN) and analyzed at the Departamento de Tecnologia e Ciência de Alimentos of the Universidade Federal de Santa Maria. The following chromatic characteristics were analyzed: CIEL*a*b coordinates *L, *a and *b, cylindrical coordinates H* (hue angle) and C* (chroma), color intensity, hue and percentages of yellow, red and blue. Physicochemical parameters alcohol content, total acidity, pH, total phenolics content and anthocyanins were also determined. The wines from the Central region had the highest values of hue angle H* and the highest average of lightness. Samples from the Campanha region were characterized by the lowest average of hue. The wines from the Serra do Nordeste region were those with the highest average of croma, anthocyanins and total phenolics content. All wines were in accordance with Brazilian legislation for total acidity. However, pH values were high (near 4.0), which favors the development of bacteria. By the analysis of the results obtained in the chromatic and physical-chemical properties of the samples, it was possible to establish a comparison between Cabernet Sauvignon wines produced in Rio Grande do Sul, in different seasons and different wine regions, to support the quest for quality improvement in production of fine wines in the state.