Nebbiolo is one of more cultivated red varieties in Western Alps of Italy. The aim of this work was to evaluated the phenolic maturity in four vineyards in Carema DOC wine production area during 2008 harvest. Moreover phenolic maturity indexes were studied in berries with different content of soluble solids. The berries of one vineyard were calibrated according to density (flotation in NaCl solutions) into four groups containing from 200 g/L to 247 g/L sugar. The phenol extractability indices (EA% and Mp%), the total content of anthocyanins (A1), the easily extractable anthocyanins (A3.2) and the total flavonoid (FT1) and the extractability (FT3.2) content were determined. The anthocyanins content change from 530 to 700 mg/kg in the four different vineyard, instead the flavonoid content is more homogeneous (ca 3000 mg/kg). The grapes with high anthocyanin content has also the higher extractability (small EA% indices). In the same vineyard, the values of anthocyanin extract to pH1 and pH3,2 increase significantly with the rise of the sugar content. However no differences were found between EA% and Mp% indices in dependence of different solid soluble classes. The results show important differences within the same sample between the different berries to the increasing of the solid soluble content, especially in the phenol concentrations. These difference are more evident in grape growing in mountain, because of climatic conditions that limit the ripeness.
Phenolic maturity of Nebbiolo grapes growing in mountain areas: monitoring and influence of sugar content
TORCHIO, FABRIZIO;ROLLE, Luca Giorgio Carlo;GIACOSA, SIMONE;GERBI, Vincenzo
2010-01-01
Abstract
Nebbiolo is one of more cultivated red varieties in Western Alps of Italy. The aim of this work was to evaluated the phenolic maturity in four vineyards in Carema DOC wine production area during 2008 harvest. Moreover phenolic maturity indexes were studied in berries with different content of soluble solids. The berries of one vineyard were calibrated according to density (flotation in NaCl solutions) into four groups containing from 200 g/L to 247 g/L sugar. The phenol extractability indices (EA% and Mp%), the total content of anthocyanins (A1), the easily extractable anthocyanins (A3.2) and the total flavonoid (FT1) and the extractability (FT3.2) content were determined. The anthocyanins content change from 530 to 700 mg/kg in the four different vineyard, instead the flavonoid content is more homogeneous (ca 3000 mg/kg). The grapes with high anthocyanin content has also the higher extractability (small EA% indices). In the same vineyard, the values of anthocyanin extract to pH1 and pH3,2 increase significantly with the rise of the sugar content. However no differences were found between EA% and Mp% indices in dependence of different solid soluble classes. The results show important differences within the same sample between the different berries to the increasing of the solid soluble content, especially in the phenol concentrations. These difference are more evident in grape growing in mountain, because of climatic conditions that limit the ripeness.
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