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DeterminaĆ§Ć£o de metais em vinho da Madeira e rum da Madeira
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Authors
Abstract(s)
VĆ”rios trabalhos tĆŖm sido publicados sobre a composiĆ§Ć£o mineral dos vinhos.
Dos elementos mais estudados, destacam-se cobre e ferro (em vinhos e aguardentes)
e sĆ³dio unicamente nos vinhos.
No presente trabalho, as determinaƧƵes analĆticas destes metais, foram
realizadas por Espetrofotometria de AbsorĆ§Ć£o AtĆ³mica (EAA) por chama, em Vinho da
Madeira e Rum da Madeira (este Ćŗltimo pela primeira vez). As implementaƧƵes das metodologias da OIV apresentaram uma boa linearidade (R2> 0,999), alta sensibilidade
e precisĆ£o (boa repetibilidade e reprodutibilidade). As taxas de recuperaĆ§Ć£o foram
prĆ³ximas dos 100 %. Uma vez validada e analisada a aplicabilidade das metodologias
nas duas matrizes em estudo, foram estudadas as variaƧƵes nos teores dos elementos
referidos acima em amostras de Vinho da Madeira (41 amostras) e Rum da Madeira
(34 amostras) com base em trĆŖs parĆ¢metros. Os resultados obtidos por EAA foram
tambƩm comparados com os resultados por colorimetria para o cobre e ferro em
Vinho da Madeira.
No Vinho da Madeira observou-se que apenas um dos produtores tem registos
superiores ao limite mĆ”ximo recomendado pela OIV para o cobre e sĆ³dio. O grau de
doƧura dos vinhos e a idade sĆ£o variĆ”veis a ter em consideraĆ§Ć£o, sendo que vinhos
mais doces e com um envelhecimento mais prolongado, sĆ£o os que apresentam
maiores teores de cobre, ferro e sĆ³dio.
Nas amostras de Rum da Madeira, a concentraĆ§Ć£o de cobre Ć© cerca de trĆŖs
vezes superior Ć do ferro, sendo as amostras de Rum da Madeira Natural aquelas que
mais contribuem para esta situaĆ§Ć£o. A nĆvel do processo de maturaĆ§Ć£o em casco,
ambos os metais registam tendĆŖncia crescente, mais significativa nos primeiros anos
de envelhecimento.
A comparaĆ§Ć£o dos resultados por EAA e por colorimetria em Vinho da Madeira
demonstram que os valores quantificados sĆ£o tendencialmente superiores na
colorimetria para os dois elementos em anƔlise.
Several papers have been published on the mineral composition of wines. Among the most studied elements, copper and iron (in wines and spirits beverages) and sodium are only prominent in wines. In the present work, the analytical determinations of these metals were performed by Flame Atomic Absorption Spectrometry (AAS) in Madeira Wine and Rum of Madeira (the latter for the first time). The implementations of the OIV methodologies presented good linearity (R2> 0.999), high sensitivity and precision (good repeatability and reproducibility). Recovery rates were close to 100%. Once validated and analyzed the applicability of the same in the two matrices under study, the variations in the contents of the mentioned elements were studied in samples of Madeira Wine (41 bottles) and Rum of Madeira (34 bottles) based on three parameters. The results obtained by AAS were also compared with the results by colorimetry for copper and iron in Madeira Wine. In Madeira Wine it was observed that only one of the producers has registrations above the maximum limit recommended by the OIV for copper and sodium. The degree of sweetness of wines and age are variables to be taken into consideration, with sweeter wines with a longer ageing, which have higher copper, iron and sodium contents. In Rum of Madeira, the concentration of copper is about three times higher than that of iron, and the samples of Rum Natural are the ones that contribute most to this situation. In the oak wood maturation process, both metals have a growing tendency, more significant in the first years of ageing. The comparison of the results by AAS and colorimetry in Madeira Wine shows that the quantified values tend to be higher in the colorimetry for the two elements under analysis.
Several papers have been published on the mineral composition of wines. Among the most studied elements, copper and iron (in wines and spirits beverages) and sodium are only prominent in wines. In the present work, the analytical determinations of these metals were performed by Flame Atomic Absorption Spectrometry (AAS) in Madeira Wine and Rum of Madeira (the latter for the first time). The implementations of the OIV methodologies presented good linearity (R2> 0.999), high sensitivity and precision (good repeatability and reproducibility). Recovery rates were close to 100%. Once validated and analyzed the applicability of the same in the two matrices under study, the variations in the contents of the mentioned elements were studied in samples of Madeira Wine (41 bottles) and Rum of Madeira (34 bottles) based on three parameters. The results obtained by AAS were also compared with the results by colorimetry for copper and iron in Madeira Wine. In Madeira Wine it was observed that only one of the producers has registrations above the maximum limit recommended by the OIV for copper and sodium. The degree of sweetness of wines and age are variables to be taken into consideration, with sweeter wines with a longer ageing, which have higher copper, iron and sodium contents. In Rum of Madeira, the concentration of copper is about three times higher than that of iron, and the samples of Rum Natural are the ones that contribute most to this situation. In the oak wood maturation process, both metals have a growing tendency, more significant in the first years of ageing. The comparison of the results by AAS and colorimetry in Madeira Wine shows that the quantified values tend to be higher in the colorimetry for the two elements under analysis.
Description
Keywords
Vinho Madeira Rum da Madeira Metais Espetrofotometria de absorĆ§Ć£o atĆ³mica Colorimetria Madeira wine Rum of Madeira Metals Atomic absorption spectrophotometry Colorimetry BioquĆmica Aplicada . Faculdade de CiĆŖncias Exatas e da Engenharia