Estudo da composição fenólica das diferentes partes do bago de castas Vitis vinifera cultivada na Região Demarcada do Douro
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2022-02-24
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A produção de uvas de qualidade é muito importante a nível mundial. Assim, o presente trabalho teve como principal objetivo a caracterização fenólica de algumas castas produzidas na Região Demarcada do Douro (RDD), e a sua comparação em dois anos consecutivos. As castas do presente trabalho estão pouco estudadas, nomeadamente no que diz respeito à sua composição fenólica e mineral das diferentes partes do bago (peliculas, polpa e grainhas). Assim, este trabalho consistiu no estudo da composição fenólica da película e das grainhas de 5 castas tintas cultivadas na RDD, Cabernet Sauvignon, Tinta Barroca, Tinta Roriz, Touriga Nacional, e Touriga Franca e da composição mineral da polpa das mesmas castas, em dois anos de vindima. Os resultados obtidos mostram que o teor de compostos fenólicos totais (2,61 a 4,66 abs/g de película em 2015 e 1,44 a 2,72 abs/g de película em 2016), antocianinas totais (3,74 a 6,95 mg/g de película em 2015 e 0,96 a 2,05 mg/g de película em 2016) e taninos totais (0,26 a 10,26 mg/g de película em 2015 e 3,47 a 3,63 mg/g de película em 2016) presentes nas películas são significativamente diferentes entre as castas e entre anos, apresentando de um modo geral o ano de 2016 valores menores. A casta Touriga Franca destaca-se como sendo a casta que apresenta maior concentração de antocianinas totais nas peliculas dos dois anos de vindima. Também se verificou que no perfil das antocianinas monoméricas a casta Touriga Franca apresenta maior concentração de malvidina-3-glucósido, malvidina-3-acetilglucósido e de malvidina-3-cumarilglucósido. Já o teor de compostos fenólicos totais (3,56 e 8,14 abs/g de grainha em 2015 e 2,39 e 3,19 abs/g de grainha em 2016) e taninos totais (2,28 e 15,55 mg/g de grainha em 2015 e 3,38 a 3,56 mg/g de grainha em 2016) na grainha também apresentavam diferenças significativas entre as castas e entre o ano de 2015 e 2016. Os resultados obtidos são importantes para o sector vitivinícola, nomeadamente para o controlo do tempo de macerações e do número de remontagens com o intuito de otimizar a extração de compostos responsáveis pela cor e de taninos.
The production of quality grapes is very important worldwide. Thus, the main objective of this work was to characterize the phenolic compositions of some grape varieties produced in the Douro Demarcated Region (RDD), and its comparison in two consecutive vintages. The varieties used in this work are few studied, namely regarding the phenolic. and minerals composition from the different parts of the grape berry (skin, pulp, and seeds). Thus, this work consisted of the study of the phenolic composition of the skin and seeds of 5 red grape varieties grown in the RDD, Cabernet Sauvignon, Tinta Barroca, Tinta Roriz, Touriga Nacional, and Touriga Franca, and the mineral composition of the pulp of the same grape varieties, of two consecutive vintages. The results obtained show that the content of total phenolic compounds (2.61 to 4.66 abs/g of skin in 2015 and 1.44 to 2.72 abs/g of skin in 2016), total anthocyanin’s (3.74 to 6.95 mg/g of skin in 2015 and 0.96 to 2.05 mg/g of skin in 2016) and total tannins (0.26 to 10.26 mg/g of skin in 2015 and 3.47 to 3.63 mg/ g of skin in 2016) present in skins are significantly different between varieties and between years, with generally the year 2016 having lower values. The Touriga Franca variety is the grape variety with the highest concentration of total anthocyanin’s in the skins during the two harvest years studied. It was also verified that in the anthocyanin’s profile, Touriga Franca grape variety presents a higher concentration of malvidin-3-glucoside, malvidin-3-acetylglucoside and malvidin-3-coumarylglucoside. The content of total phenolic compounds (3.56 and 8.14 abs/g of seed in 2015 and 2.39 and 3.19 abs/g of seed in 2016) and total tannins (2.28 and 15.55 mg /g of seed in 2015 and 3.38 to 3.56 mg/g of seed in 2016) in the seed were also significant differences between the grape varieties and between the year 2015 and 2016. The results obtained are important for the wine sector, namely for the control of maceration time and the number of pumping over in order to optimize the extraction of compounds responsible for the colour and tannins.
The production of quality grapes is very important worldwide. Thus, the main objective of this work was to characterize the phenolic compositions of some grape varieties produced in the Douro Demarcated Region (RDD), and its comparison in two consecutive vintages. The varieties used in this work are few studied, namely regarding the phenolic. and minerals composition from the different parts of the grape berry (skin, pulp, and seeds). Thus, this work consisted of the study of the phenolic composition of the skin and seeds of 5 red grape varieties grown in the RDD, Cabernet Sauvignon, Tinta Barroca, Tinta Roriz, Touriga Nacional, and Touriga Franca, and the mineral composition of the pulp of the same grape varieties, of two consecutive vintages. The results obtained show that the content of total phenolic compounds (2.61 to 4.66 abs/g of skin in 2015 and 1.44 to 2.72 abs/g of skin in 2016), total anthocyanin’s (3.74 to 6.95 mg/g of skin in 2015 and 0.96 to 2.05 mg/g of skin in 2016) and total tannins (0.26 to 10.26 mg/g of skin in 2015 and 3.47 to 3.63 mg/ g of skin in 2016) present in skins are significantly different between varieties and between years, with generally the year 2016 having lower values. The Touriga Franca variety is the grape variety with the highest concentration of total anthocyanin’s in the skins during the two harvest years studied. It was also verified that in the anthocyanin’s profile, Touriga Franca grape variety presents a higher concentration of malvidin-3-glucoside, malvidin-3-acetylglucoside and malvidin-3-coumarylglucoside. The content of total phenolic compounds (3.56 and 8.14 abs/g of seed in 2015 and 2.39 and 3.19 abs/g of seed in 2016) and total tannins (2.28 and 15.55 mg /g of seed in 2015 and 3.38 to 3.56 mg/g of seed in 2016) in the seed were also significant differences between the grape varieties and between the year 2015 and 2016. The results obtained are important for the wine sector, namely for the control of maceration time and the number of pumping over in order to optimize the extraction of compounds responsible for the colour and tannins.
Descrição
Este trabalho foi elaborado com vista à obtenção do grau de mestre em Engenharia Alimentar da Universidade de Trás-os-Montes e Alto Douro.
Palavras-chave
Compostos fenólicos totais , antocianinas