| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 4.3 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
A indústria corticeira enfrenta um problema grave desde a década de 90, a contaminação das rolhas por 2,4,6-tricloroanisol (TCA). Este composto contamina a rolha e a sua transmissão para os vinhos confere um sabor e aroma a mofo inibindo as particularidades gustativas dos mesmos. A maneira como essa transmissão ocorre vai ser alvo de estudo na presente dissertação, especificamente, qual a capacidade do TCA migrar da rolha para o vinho. O TCA faz parte de uma família de compostos em que nem todos são prejudiciais, alguns compostos fenólicos são benéficos e atuam como antioxidantes protegendo o vinho da oxidação. No entanto, essa capacidade é destruída pela reação dos mesmos com o peróxido de hidrogénio proveniente do processo industrial lavação. Na presente dissertação também vamos estudar um método eficaz de regenerar os compostos fenólicos oxidados. Para determinar a capacidade migratória de TCA foram efetuados vários estudos com variações no tipo de rolha, local e/ou quantidade de contaminação. Para o estudo de migração natural contaminaram-se as rolhas a três profundidades diferentes, onde se determinou que ocorre migração nas contaminações mais profundas para o vinho mas, nas contaminações menos profundas mantem-se incapaz de migrar para o vinho. Para as rolhas de champanhe variaram-se as contaminações entre os discos de cortiça natural interior e exterior e, o corpo da rolha feito de granulado. Os resultados foram conclusivos e demonstraram que existe migração dos discos contaminados para o vinho. As contaminações nos corpos foram incapazes de contaminar os vinhos. Este resultado repetiu-se quando foi feito um estudo às capacidades migratórias das rolhas de champanhe variando apenas a contaminação dos corpos. No estudo da regeneração de compostos fenólicos, através do método de análise FRAP, DPPH e Folin-Ciocalteu, observou-se que com um tratamento de 24 horas de solução de dióxido de enxofre os compostos fenólicos das rolhas retornam ao seu estado redutor. Isto traduz-se no aumento da capacidade antioxidante.
The cork industry has faced a serious problem since the 1990s, the contamination of corks by 2,4,6-trichloroanisole (TCA). This compound contaminates the cork and its transmission to the wines confers a taste and scent of mold, inhibiting the gustatory peculiarities of the wines. The manner in which this transmission takes place will be the subject of study in the present dissertation, specifically, the capacity of the TCA to migrate from the cork to the wine. TCA is part of a family of compounds in which not all are harmful, some phenolic compounds are beneficial and act as antioxidants protecting wine from oxidation. However, this capacity is destroyed by the reaction of the same with the hydrogen peroxide from the industrial washing process. In the present dissertation we will also study an effective method of regenerating the oxidized phenolic compounds. To determine the migratory capacity of TCA, several studies were carried out with variations in the type of cork, local and / or amount of contamination. For the study of natural migration the corks were contaminated at three different depths, where it was determined that migration occurs in the deeper contaminations but, in the shallower contaminations, it remains unable to migrate to the wine. For the champagne corks the contaminations between the inner and outer natural cork disks and the body of the cork made of granulate were varied. The results were conclusive and showed that there is migration of contaminated disks to the wine. The contaminations in the bodies were unable to contaminate the wines. This result was repeated when a study of the migratory capacities of champagne corks was done, varying only the contamination of the bodies. In the study of the regeneration of phenolic compounds, through the FRAP, DPPH and FolinCiocalteau analysis, it was observed that with a 24 hour treatment of sulfur dioxide solution the stoppers recover the phenolic compounds to their reducing state. This translates into increased antioxidant capacity.
The cork industry has faced a serious problem since the 1990s, the contamination of corks by 2,4,6-trichloroanisole (TCA). This compound contaminates the cork and its transmission to the wines confers a taste and scent of mold, inhibiting the gustatory peculiarities of the wines. The manner in which this transmission takes place will be the subject of study in the present dissertation, specifically, the capacity of the TCA to migrate from the cork to the wine. TCA is part of a family of compounds in which not all are harmful, some phenolic compounds are beneficial and act as antioxidants protecting wine from oxidation. However, this capacity is destroyed by the reaction of the same with the hydrogen peroxide from the industrial washing process. In the present dissertation we will also study an effective method of regenerating the oxidized phenolic compounds. To determine the migratory capacity of TCA, several studies were carried out with variations in the type of cork, local and / or amount of contamination. For the study of natural migration the corks were contaminated at three different depths, where it was determined that migration occurs in the deeper contaminations but, in the shallower contaminations, it remains unable to migrate to the wine. For the champagne corks the contaminations between the inner and outer natural cork disks and the body of the cork made of granulate were varied. The results were conclusive and showed that there is migration of contaminated disks to the wine. The contaminations in the bodies were unable to contaminate the wines. This result was repeated when a study of the migratory capacities of champagne corks was done, varying only the contamination of the bodies. In the study of the regeneration of phenolic compounds, through the FRAP, DPPH and FolinCiocalteau analysis, it was observed that with a 24 hour treatment of sulfur dioxide solution the stoppers recover the phenolic compounds to their reducing state. This translates into increased antioxidant capacity.
Description
Keywords
Migração Rolha de champanhe Rolha natural TCA Cortiça Quinonas Antioxidante Regeneração Migration Champagne cork Natural cork Cork Quinones Antioxidant Regeneration