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Abstract(s)
A estabilidade físico-química de um vinho, como a estabilidade tartárica, são fatores fundamentais para a aceitabilidade desta bebida no mercado, face aos requisitos dos consumidores atuais. Os fenómenos de precipitação tartárica ocorrem de forma natural e imprevisível, tornando-se imprescindível avaliar este tipo de instabilidade no processo de produção dos vinhos.
A autorização da adição da carboximetilcelulose (CMC) ao vinho, desde 2009 ((UE) 606/2009), veio disponibilizar uma nova forma de se estabilizar o vinho a nível tartárico. Este olímero é caracterizado essencialmente pelo seu peso molecular e grau de substituição, parâmetros que afetam diretamente a sua solubilidade em água.
O principal objetivo do projeto realizado, foi a preparação de soluções aquosas de diferentes tipos de CMC de forma a verificar qual o intervalo de peso molecular e grau de substituição mais indicado para preparar misturas de carboximetilcelulose com goma arábica, com o propósito de permitir a estabilização tartárica de diferentes vinhos.
O CMC testado (CMCb) com um grau de substituição de 0,77 e peso molecular de 20 kDa, foi o único que permitiu a preparação de misturas de CMC com goma arábica, do tipo Seyal ou Verek.
Através dos ensaios realizados pode verificar-se ainda, que o CMCb demonstrou poder estabilizante a nível tartárico tanto na forma elementar (CMC), como em diferentes misturas (GA + CMC), quando aplicado em vinhos tintos, brancos e rosados.
The physical-chemical stability of a wine, such as tartaric stability, are fundamental factors for the acceptability of this drink in the market, face to the requirements of the current consumers. The phenomena of tartaric precipitation occur naturally and unpredictably, becoming crucial to evaluate this type of instability in the wine production process. The authorization of the addition of carboxymethylcellulose (CMC) to the wine, since 2009 ((EU) 606/2009), provided a new way to stabilize the wine at a tartaric level. This polymer is characterized essentially by his molecular weight and degree of substitution, parameters that directly affect his solubility in water. The main objective of the project was the preparation of aqueous solutions of diferente types of CMC, with the purpose of verifying which molecular weight range and degree of substitution is the most suited to prepare mixtures of carboxymethylcellulose with arabic gum, in order to allow the stabilization of different wines. The tested CMC (CMCb) which shows a substitution degree of 0.77 and molecular weight of 20 kDa was the only one, that allowed the preparation of CMC mixtures with arabic gum, Seyal or Verek type. Through the tests carried out it can be verified that the CMCb has a stabilizing power at a tartaric level, either in elemental form (CMC) or in different mixtures (GA+CMC), when applied in red, white and rose wines.
The physical-chemical stability of a wine, such as tartaric stability, are fundamental factors for the acceptability of this drink in the market, face to the requirements of the current consumers. The phenomena of tartaric precipitation occur naturally and unpredictably, becoming crucial to evaluate this type of instability in the wine production process. The authorization of the addition of carboxymethylcellulose (CMC) to the wine, since 2009 ((EU) 606/2009), provided a new way to stabilize the wine at a tartaric level. This polymer is characterized essentially by his molecular weight and degree of substitution, parameters that directly affect his solubility in water. The main objective of the project was the preparation of aqueous solutions of diferente types of CMC, with the purpose of verifying which molecular weight range and degree of substitution is the most suited to prepare mixtures of carboxymethylcellulose with arabic gum, in order to allow the stabilization of different wines. The tested CMC (CMCb) which shows a substitution degree of 0.77 and molecular weight of 20 kDa was the only one, that allowed the preparation of CMC mixtures with arabic gum, Seyal or Verek type. Through the tests carried out it can be verified that the CMCb has a stabilizing power at a tartaric level, either in elemental form (CMC) or in different mixtures (GA+CMC), when applied in red, white and rose wines.
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Keywords
Vinho Estabilidade tartárica Carboximetilcelulose Goma arábica Wine Tartaric stability Carboxymethylcellulose Arabic gum