Free and bound compounds of 12 white or coloured aromatic vines, including two white muscat biotypes grown in a collection vineyard, have been extracted from grapes using a new method and separated by gas-chromatography . Terpenic profile of every variety was described and ratios between isomers and between compounds considered important in terpenic synthesis were calculated. Cultivars were divided in groups basis of this above parametres. The content of three main monohydroxilated alcohols (linalool, nerol and geraniol) has allowed a first distinction in: 1) cultivars with a quite high content of linalool, as ‘Moscato giallo’, ‘Early Muscat’, ‘Muscat Ot-tonel’, ‘Muscat de Frontignan rouge’, ‘White Muscat Queensland’, ‘Moscato bianco’ 1 and ‘Mos-cato bianco’ 2; 2) cultivar with a high content of geraniol as ‘Moscato rosa’, ‘Orange Muscat’ and ‘Muskat Ham-burg’; 3) cultivar with a high content of nerol as ’Orange Muscat’, ‘Moscato rosa’, ’Moscato giallo’, ‘Muscat de Frontignan rouge’, ‘Moscato bianco’ 2 and ‘Moscatel Roxo’; 4) cultivar with a very low content of linalool as ‘Muskat Hamburg’ and ‘Muskat violett, which has also a content of geraniol lower than other cultivars. Ratio between contents of free linalool and geraniol allow the division of cultivars in two groups: 1) cultivar with a terpenic composition similar to those of ‘White Muscat’, that is with the ratio free linalol/geraniol 1. 2) cultivar with terpenic composition similar to the one of aromatic coloured grapevine cultivars from Italian Piedmont, that is with the ratio free linalool/geraniol < 1. In the first group there are ‘White Muscat Queensland’, ‘Moscato bianco’ 1, ‘Moscato bianco’ 2, ‘Moscato giallo’, ‘Muscat de Frontignan rouge’, ‘Muscat Ottonel’, ‘Early Muscat’ and ‘Moscatel Roxo’, in the second there are ‘Muskat Violett’, ‘Moscato rosa’, ’Muskat Hamburg’, ‘Primus’ and ‘Orange Muscat’. In these two groups it is possible to notice some important differences among cultivars, for that it is necessary to do further divisions on the basis of absolute content of other terpenic compounds, such as diol 1, 8-hydroxy linalool cis and trans, furan and piran-linalool oxides and geranic acid, and of ratios between some important key terpenic compounds. The analysis of absolute contents combined with these ratios has permitted to create the fallowing five groups: 1. ‘Muscat Ottonel’, ‘Early Muscat’ 2. ‘Moscato giallo’, ’Muscat de Frontignan rouge’, ’Moscato bianco’ 1, ‘Moscato bianco’ 2 3. ‘Orange Muscat’, ‘Moscatel Roxo’ 4. ‘White Muscat Queensland’, ’Moscato rosa’ 5. ‘Muscat Hamburg’, ‘Muskat Violett’, ‘Primus’ Aromatic cultivars have therefore similar behavior in basic terpenic compound (geraniol, nerol and linalool) synthesis, but subsequent processes, that take at their epoxydation, hydroxylation and cy-clizzation are characteristic of every cultivar.
Profilo terpenico di vitigni aromatici.
GUIDONI, Silvia;
1999-01-01
Abstract
Free and bound compounds of 12 white or coloured aromatic vines, including two white muscat biotypes grown in a collection vineyard, have been extracted from grapes using a new method and separated by gas-chromatography . Terpenic profile of every variety was described and ratios between isomers and between compounds considered important in terpenic synthesis were calculated. Cultivars were divided in groups basis of this above parametres. The content of three main monohydroxilated alcohols (linalool, nerol and geraniol) has allowed a first distinction in: 1) cultivars with a quite high content of linalool, as ‘Moscato giallo’, ‘Early Muscat’, ‘Muscat Ot-tonel’, ‘Muscat de Frontignan rouge’, ‘White Muscat Queensland’, ‘Moscato bianco’ 1 and ‘Mos-cato bianco’ 2; 2) cultivar with a high content of geraniol as ‘Moscato rosa’, ‘Orange Muscat’ and ‘Muskat Ham-burg’; 3) cultivar with a high content of nerol as ’Orange Muscat’, ‘Moscato rosa’, ’Moscato giallo’, ‘Muscat de Frontignan rouge’, ‘Moscato bianco’ 2 and ‘Moscatel Roxo’; 4) cultivar with a very low content of linalool as ‘Muskat Hamburg’ and ‘Muskat violett, which has also a content of geraniol lower than other cultivars. Ratio between contents of free linalool and geraniol allow the division of cultivars in two groups: 1) cultivar with a terpenic composition similar to those of ‘White Muscat’, that is with the ratio free linalol/geraniol 1. 2) cultivar with terpenic composition similar to the one of aromatic coloured grapevine cultivars from Italian Piedmont, that is with the ratio free linalool/geraniol < 1. In the first group there are ‘White Muscat Queensland’, ‘Moscato bianco’ 1, ‘Moscato bianco’ 2, ‘Moscato giallo’, ‘Muscat de Frontignan rouge’, ‘Muscat Ottonel’, ‘Early Muscat’ and ‘Moscatel Roxo’, in the second there are ‘Muskat Violett’, ‘Moscato rosa’, ’Muskat Hamburg’, ‘Primus’ and ‘Orange Muscat’. In these two groups it is possible to notice some important differences among cultivars, for that it is necessary to do further divisions on the basis of absolute content of other terpenic compounds, such as diol 1, 8-hydroxy linalool cis and trans, furan and piran-linalool oxides and geranic acid, and of ratios between some important key terpenic compounds. The analysis of absolute contents combined with these ratios has permitted to create the fallowing five groups: 1. ‘Muscat Ottonel’, ‘Early Muscat’ 2. ‘Moscato giallo’, ’Muscat de Frontignan rouge’, ’Moscato bianco’ 1, ‘Moscato bianco’ 2 3. ‘Orange Muscat’, ‘Moscatel Roxo’ 4. ‘White Muscat Queensland’, ’Moscato rosa’ 5. ‘Muscat Hamburg’, ‘Muskat Violett’, ‘Primus’ Aromatic cultivars have therefore similar behavior in basic terpenic compound (geraniol, nerol and linalool) synthesis, but subsequent processes, that take at their epoxydation, hydroxylation and cy-clizzation are characteristic of every cultivar.
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