3-Alquil-2-metoxipirazines en mostos i vins: determinació analítica i estudi de la influència d'alguns factors vitivinícoles
3-alkyl-2-methoxypirazines are found in many plants, Vitis vinifera among them. The most important ones regarding theire presence and potential influence on the flavor of wine are: 3-isobutyl-, 3-sec-butyl, and 3-isopropyl-2-methoxypyrazine. Those compounds can be found amongh the varietal aromas of...
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| Tipo de documento: | tese |
| Estado: | Versão publicada |
| Data de publicação: | 2004 |
| País: | España |
| Recursos: | Universitat Rovira i virgili (URV) |
| Repositório: | Repositori Institucional de la Universitat Rovira i Virgili |
| OAI Identifier: | oai:urv.cat:TDX:434 |
| Acesso em linha: | https://hdl.handle.net/20.500.11797/TDX434 http://hdl.handle.net/10803/8653 |
| Access Level: | Acceso aberto |
| Palavra-chave: | 663/664 - Aliments i nutrició. Enologia. Olis. Greixos 634 - Horticultura. Viticultura 577 - Bioquímica. Biologia molecular. Biofísica 543 - Química analítica |
| Resumo: | 3-alkyl-2-methoxypirazines are found in many plants, Vitis vinifera among them. The most important ones regarding theire presence and potential influence on the flavor of wine are: 3-isobutyl-, 3-sec-butyl, and 3-isopropyl-2-methoxypyrazine. Those compounds can be found amongh the varietal aromas of Cabernet sauvignon, but also in Merlot noir, Sauvignon blanc and Cabernet franc, among other.The 'vegetative' character that the 3-alkyl-2-methoxypirazines provide to wines is generally considered a low quality factor, since it is associated to the lack of maturity of the grapes at harvest. The possibility of monitoring the contents of those compounds in grapes, must and wines during ripening and winemaking is interesting to producers, since it could allow them to optimize the parameters of pruning, sunlight exposure, press, fermentation and even coupage of wines in order to obtain a final product with the maximum quality.The objective of this work is the development of a method based on gas chromatography with nitrogen-phosphorous detection, in order to quantify the 3-alkyl-2-methoxpyrazines with oenology interest, in musts and wines. The levels of those compounds have been monitored during grape ripening and wine making of experimental samples. Finally, the possible influence of certain ripening conditions has been studied: sunlight exposure, irrigation, vine training and plantation density. 3-alkyl-2-methoxypyrazines are found at the ultra-trace level (ng/L) in musts and wines, in a complex matrix. Despite those low levels, they can have an influence on wine quality because their sensory percepcion thresholds are at the same level. Therefore, their analysis demands the maximum selectivity and sensitivity. In optimum conditions, the detection limits of the nitrogen-phospho |
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