Valorização de subprodutos da vinha e do vinho-composição fenólica e atividade antioxidante
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Data
2016
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O bagaço de uva é um resíduo industrial obtido a partir do processo de fabrico de vinho e grande parte do bagaço produzido pelas vinícolas é desperdiçado. Deste modo, é importante explorar subprodutos de vinícolas, como o bagaço, que apresenta propriedades fitoterápicas de importância para as indústrias farmacêuticas, químicas e de alimentos, permitindo assim agregar valor a este resíduo industrial.
O objetivo deste trabalho é determinar a atividade antioxidante usando os métodos DPPH, FRAP e ABTS, além de avaliar o teor em fenóis totais, flavonóides e taninos de subprodutos da vinha e dos vinhos (folha da videira e bagaço de uva),assim como da uva e peles de uva da casta Touriga Nacional. Estas amostras também foram analisadas por espectrometria de massa (MS). Além disso foi também realizada a validação analítica relativamente ao teor em fenóis totais, flavonóides, ABTS e FRAP.
Os resultados obtidos permitiram concluir que os métodos analíticos foram validados com sucesso. De uma forma geral o melhor método de extração de fenóis totais e de flavonóides foi o do Soxlet de 6 ciclos (D6c), sendo que a amostra com maior concentração de fenóis totais é o bagaço (BV). A amostra com maior concentração em taninos é a pele de uva (P) e a extração pelo método D6c, permite de uma forma geral obter extratos mais concentrados. O vinho A apresenta um teor superior em fenóis totais e taninos do que o vinho B. Usando o método de DPPH conclui-se que a amostra com maior atividade antioxidante foi o extrato P (método A). A amostra com maior atividade antioxidante ao se aplicar o método FRAP é a P (método D6c), enquanto que pelo método de ABTS é a amostra FV (método D6c). Os resultados demonstram uma boa correlação entre o teor em fenóis totais e flavonóides totais para as amostras P, BV e U. Estabeleceu-se a correlação entre os fenóis totais, flavonóides e a actividade antioxidante. Os resultados preliminares de identificação dos compostos por LC-MS conduziram a duas propostas de identificação de compostos (ácido tartárico e catequina em alguns dos extratos analisados) e na detecção de alguns compostos não identificados, nomeadamente com m/z=133 e m/z=341.
The grape pomace is an industrial waste obtained from the production process of wine and the most part of the bagasse produced by wineries is wasted. So it’s important to explore wine by-products such as bagasse, which showing important phytotherapeutic properties for pharmaceutical, chemical and food industries, allowing adding value to this industrial waste. The objective of this study was to determine the antioxidant activity using the methods of DPPH, FRAP and ABTS and evaluating the content of total phenols, flavonoids and tannins from vineyard and wines by-products (vine leaf and grape pomace), as well as grapes and grape skins of Touriga Nacional, these samples were also analyzed by mass spectroscopy (MS). The results showed that the analytical methods have been successfully validated. In general the best method of extraction of total phenols and flavonoids were the Soxlet 6 cycles (D6c), and the sample with the highest concentration of total phenols is the grape pomace (BV). The sample with the highest concentration in the tannin is grape skin (P) and extraction by D6c method in general allows more concentrated extracts. The wine A has a higher content of total phenols and tannins that the wine B. Applying the DPPH assay concludes that the sample with the highest antioxidant activity was the extract P (method A). The sample with the highest antioxidant activity when applying the FRAP method is the P (D6c method), while by the ABTS method is the sample FV (D6c method). The results show a good correlation between the content of total phenols and total flavonoids to the P BV and U samples. It was established the correlation between total phenols, flavonoids and antioxidant activity. The preliminary results by LC-MS lead to two identification of proposals (tartaric acid and catechin in some of the analyzed extracts) and detection of some unidentified compounds, in particular m/z = 133 and m/z = 341.
The grape pomace is an industrial waste obtained from the production process of wine and the most part of the bagasse produced by wineries is wasted. So it’s important to explore wine by-products such as bagasse, which showing important phytotherapeutic properties for pharmaceutical, chemical and food industries, allowing adding value to this industrial waste. The objective of this study was to determine the antioxidant activity using the methods of DPPH, FRAP and ABTS and evaluating the content of total phenols, flavonoids and tannins from vineyard and wines by-products (vine leaf and grape pomace), as well as grapes and grape skins of Touriga Nacional, these samples were also analyzed by mass spectroscopy (MS). The results showed that the analytical methods have been successfully validated. In general the best method of extraction of total phenols and flavonoids were the Soxlet 6 cycles (D6c), and the sample with the highest concentration of total phenols is the grape pomace (BV). The sample with the highest concentration in the tannin is grape skin (P) and extraction by D6c method in general allows more concentrated extracts. The wine A has a higher content of total phenols and tannins that the wine B. Applying the DPPH assay concludes that the sample with the highest antioxidant activity was the extract P (method A). The sample with the highest antioxidant activity when applying the FRAP method is the P (D6c method), while by the ABTS method is the sample FV (D6c method). The results show a good correlation between the content of total phenols and total flavonoids to the P BV and U samples. It was established the correlation between total phenols, flavonoids and antioxidant activity. The preliminary results by LC-MS lead to two identification of proposals (tartaric acid and catechin in some of the analyzed extracts) and detection of some unidentified compounds, in particular m/z = 133 and m/z = 341.
Descrição
Orientação: Maria Nubélia Silvestre Bravo
Palavras-chave
MESTRADO EM ENGENHARIA BIOTECNOLÓGICA, SUBPRODUTOS, VINHOS, ANTIOXIDANTES, COMPOSTOS QUÍMICOS, BIOTECHNOLOGY ENGINEERING, ENGENHARIA BIOTECNOLÓGICA, BY-PRODUCTS, WINES, ANTIOXIDANTS, CHEMICAL MIXTURES, COMPOSTOS FENÓLICOS, PHENOLIC COMPOUNDS