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Publication
Maturação de castas DOP Madeira: caracterização do verdelho
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Abstract(s)
O Verdelho é uma das castas brancas mais utilizadas na produção de vinho DOP “Madeira”, embora possa ser também utilizada na produção de vinhos tranquilos. Atualmente é uma das castas selecionadas no programa de reconversão de vinhas. Este trabalho teve como principal objetivo a caracterização da casta Verdelho durante a fase de maturação e relacionar os diferentes sistemas de condução, porta enxertos e anos de plantação com a qualidade das uvas e do vinho produzido, através de microvinificações. As uvas de 5 clones diferentes foram também caracterizadas à data da vindima. Neste estudo foram utilizadas as técnicas de cromatografia líquida e gasosa e de espetrofotometria UV-Vis, e determinados parâmetros físicoquímicos básicos para a obtenção de dados referentes às concentrações de açúcares redutores, ácidos orgânicos, compostos voláteis, cor, composição polifenólica total e índice de maturação. Os dados foram analisados estatisticamente por ANOVA e PCA. Relativamente aos fatores culturais estudados, observou-se que as vinhas em espaldeira e mais novas apresentaram cachos de dimensão e peso superiores (16-18 cm de comprimento e 450650 g de peso) e concentração mais elevada em açúcares redutores (40-50 g/L de glucose e 25-55 g/L de frutose) ao longo da maturação, assim como de compostos voláteis carbonilo (7326,03 mg/L) à data da vindima. As uvas da espaldeira de vinhas mais velhas e da latada foram as que registaram menores dimensões e pesos. Quanto às uvas dos diferentes clones foram registadas diferenças no teor de açúcares (máx.13%), ácidos orgânicos (máx. 22%) e compostos carbonilo (máx. 66%) entre eles. A análise multivariada (PCA) veio confirmar estas diferenças. Os resultados obtidos das microvinificações demonstraram que as diferenças encontradas resultam sobretudo do processo de vinificação e não da influência dos diferentes sistemas de condução, idade das vinhas e porta enxertos.
Verdelho is one of the most commonly used white grape varieties for the production of "Madeira" PDO wine, although it can also be used for the production of table wines. It is currently one of the vine varieties selected in the vineyard reconversion program. This work had as its main objectives the characterization of Verdelho grapes during the maturation stage and to establish a relationship between the different systems of vine conduction, rootstocks and years of plantation with the quality of the grapes and the wine produced, through microvinifications. The grapes of 5 different clones were also characterized at the time of harvest. Liquid and gas chromatography and UV-Vis spectrophotometry techniques were used, as well as certain basic physico-chemical parameters, to obtain the data on concentrations of reducing sugars, organic acids, volatile compounds, colour, total polyphenolic composition and index of ripeness. Data were statistically analysed by ANOVA and PCA. Regarding the cultural factors studied, it was shown that the younger vineyards in espalier presented grape bunches of larger size and weight (16-18 cm in length and 450-650 g in weight) and higher concentration in reducing sugars (40-50 g/L in glucose and 25-55 g/L in fructose) throughout its maturation, as well as volatile carbonyl compounds (7326.03 mg/L) at the time of harvest. The grapes of older vines in espalier and of the trellising system registered smaller dimensions and weights. As for the grapes of the different clones, differences in the sugar content (up to 13%), organic acids (up to 22%) and carbonyl compounds (up to 66%) were observed. A multivariate analysis (PCA) confirmed these differences. The results obtained from the microvinifications showed that the differences found resulted mainly from the vinification process and not from the influence of the different systems of conduction, age of the vines and rootstocks.
Verdelho is one of the most commonly used white grape varieties for the production of "Madeira" PDO wine, although it can also be used for the production of table wines. It is currently one of the vine varieties selected in the vineyard reconversion program. This work had as its main objectives the characterization of Verdelho grapes during the maturation stage and to establish a relationship between the different systems of vine conduction, rootstocks and years of plantation with the quality of the grapes and the wine produced, through microvinifications. The grapes of 5 different clones were also characterized at the time of harvest. Liquid and gas chromatography and UV-Vis spectrophotometry techniques were used, as well as certain basic physico-chemical parameters, to obtain the data on concentrations of reducing sugars, organic acids, volatile compounds, colour, total polyphenolic composition and index of ripeness. Data were statistically analysed by ANOVA and PCA. Regarding the cultural factors studied, it was shown that the younger vineyards in espalier presented grape bunches of larger size and weight (16-18 cm in length and 450-650 g in weight) and higher concentration in reducing sugars (40-50 g/L in glucose and 25-55 g/L in fructose) throughout its maturation, as well as volatile carbonyl compounds (7326.03 mg/L) at the time of harvest. The grapes of older vines in espalier and of the trellising system registered smaller dimensions and weights. As for the grapes of the different clones, differences in the sugar content (up to 13%), organic acids (up to 22%) and carbonyl compounds (up to 66%) were observed. A multivariate analysis (PCA) confirmed these differences. The results obtained from the microvinifications showed that the differences found resulted mainly from the vinification process and not from the influence of the different systems of conduction, age of the vines and rootstocks.
Description
Keywords
Verdelho Uvas Maturação Viticultura Sistema de condução Porta enxerto Grapes Ripening Viticulture Conduction system Rootstock Bioquímica Aplicada . Faculdade de Ciências Exatas e da Engenharia