Desenvolvimento de bebidas licorosas com elevado teor de compostos bioativos através da valorização do engaço
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2017
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A uva tem sido apontada como uma fonte rica de compostos bioativos, sendo que a sua produção é uma das principais atividades económicas do setor agro-alimentar em todo o mundo, com mais de 60 milhões de toneladas produzidas anualmente.
Encontra-se atualmente bem estabelecido na comunidade científica que os vinhos desempenham um papel preponderante ao nível da prevenção de algumas doenças do foro cardiovascular, associado ao seu conteúdo em compostos bioativos naturais com capacidade antioxidante. Estes compostos, podem ser provenientes das partes sólidas do cacho de uva (película, grainha e engaço).
Ao serem geradas grandes quantidades destes sub-produtos, a sua maioria é usada para a compostagem ou são descartados em áreas abertas, podendo provocar potenciais problemas ambientais e, consequentemente, comprometendo a sustentabilidade económica e a competitividade das indústrias vínicas.
Assim, neste trabalho, foram desenvolvidas novas formas de valorização do engaço de uva, baseado na elaboração de licores através da maceração de engaço e, posteriormente, avaliou-se o seu conteúdo polifenólico, assim como dos extratos de engaço de uva (Vitis vinifera L.) de cinco castas tintas e duas castas brancas, cultivadas na Região Demarcada do Douro. Para além do teor em compostos fenólicos, nomeadamente fenóis totais, orto-difenóis e flavonóides, analisou-se também a atividade antiradicalar por dois métodos distintos, ABTS.+ e DPPH•.
Verificaram-se diferenças significativas entre as castas estudadas, quer nos extratos de engaço como nos licores, relativamente aos parâmetros avaliados. A análise das diferentes castas permitiu verificar que as castas tintas apresentam teores em compostos fenólicos e atividade antiradicalar superiores às castas brancas, sendo a casta ‘Tinto Cão’ a mais promissora, uma vez que apresentou valores de composição fenólica superiores a todas as castas analisadas.
Grape has been identified as a rich source of bioactive compounds, and its production is one of the main economic activities of the agri-food sector worldwide, with over 60 million tons produced annually. It is currently well established in the scientific community that wines play a major role in the prevention of some cardiovascular diseases, associated with their content in natural bioactive compounds with antioxidant capacity. These compounds may come from the solid parts of the bunch of grapes (film, seed and stems). When large quantities of these by-products are generated, most of them are used for composting or are discarded in open areas, which may lead to potential environmental problems and, consequently, compromising the economic sustainability and competitiveness of the wine industry. Thus, in this work, new forms of grape stems valorization were developed, based on the elaboration of liqueurs through the maceration of stems and, later, their polyphenolic content were evaluated, as well as of grape stems extracts (Vitis vinifera L.) of five red varieties and two white varieties, grown in the Douro Demarcated Region. In addition to the content of phenolic compounds, namely total phenols, ortho-diphenols and flavonoids, the antiradicalar activity was also analyzed by two different methods, ABTS and DPPH. There were significant differences between the studied varieties, both in the extract and in the liqueurs, in relation to the evaluated parameters. The analysis of the different varieties allowed to verify that the red varieties showed phenolic compounds and antiradicalar activity superior to the white varieties, being the breed 'Tinto Cão' the most promising, since it presented values of phenolic composition superior to all the analyzed grape varieties.
Grape has been identified as a rich source of bioactive compounds, and its production is one of the main economic activities of the agri-food sector worldwide, with over 60 million tons produced annually. It is currently well established in the scientific community that wines play a major role in the prevention of some cardiovascular diseases, associated with their content in natural bioactive compounds with antioxidant capacity. These compounds may come from the solid parts of the bunch of grapes (film, seed and stems). When large quantities of these by-products are generated, most of them are used for composting or are discarded in open areas, which may lead to potential environmental problems and, consequently, compromising the economic sustainability and competitiveness of the wine industry. Thus, in this work, new forms of grape stems valorization were developed, based on the elaboration of liqueurs through the maceration of stems and, later, their polyphenolic content were evaluated, as well as of grape stems extracts (Vitis vinifera L.) of five red varieties and two white varieties, grown in the Douro Demarcated Region. In addition to the content of phenolic compounds, namely total phenols, ortho-diphenols and flavonoids, the antiradicalar activity was also analyzed by two different methods, ABTS and DPPH. There were significant differences between the studied varieties, both in the extract and in the liqueurs, in relation to the evaluated parameters. The analysis of the different varieties allowed to verify that the red varieties showed phenolic compounds and antiradicalar activity superior to the white varieties, being the breed 'Tinto Cão' the most promising, since it presented values of phenolic composition superior to all the analyzed grape varieties.
Descrição
Dissertação de Mestrado em Enologia
Palavras-chave
Vitis vinifera , Engaço de uva , Licores de engaço , Compostos polifenólicos , Atividade antiradicalar