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dc.contributor.advisorBarros, Ana Isabel Ramos Novo Amorim Dept_PT
dc.contributor.advisorGouvinhas, Irenept_PT
dc.contributor.authorSousa, Lucinda Margarida Oliveira dept_PT
dc.descriptionDissertação de Mestrado em Engenharia Alimentar – Qualidade Alimentarpt_PT
dc.description.abstracta cerveja adquira um potencial antioxidante que apresenta benefícios à saúde de quem a consome, indiferentemente da marca, já que todas apresentaram semelhante padrão de compostos (fenólicos), podendo assim desprover principalmente de ação anti-ateroscleróticas, anti-inflamatórias e anti-carcinogénicaspt_PT
dc.description.abstractBeer is one of the most appreciated and consumed drinks worldwide. The varied styles of beer are based on a combination of ingredients, processing and cultural factors. However, the differentiation between styles of beer is mainly caused by variations in the substrate level (must) to the detriment of variations arising from fermentation. Although the yeast plays a key role in the sensory development of beer, beer fermentation is accomplished by a limited variety of yeast strains, which are mostly belonging to the genus Saccharomyces. Beer is considered a food with potential beneficial health effects due to its phenolic compounds with antioxidant property. This study aimed to evaluate the antioxidant activity from different beer fermentation types and different brands sold in national supermarkets, as well as the phenolic composition, namelly the total phenolic content by the Folin-Ciocalteau method, the ortho-diphenols content and flavonoids, of 23 beers selected. Futhermore, the identification of phenolic compounds was performed by HPLC-DAD. Relatively to the content of ortho-diphenols, the "white 7 beer" revealed to be the beer with the higher concentration with1,801 ± 0,087 g AG / L. Regarding the total flavonoids and phenols, the results showed that the "black 2 beer" had a higher concentration, with a content of 0,151 ± 0,017 g CAT / L and 0,824 ± 0,074 g AG / L, respectively. For the quantification of the phenolic compounds by HPLC, the main compound identified was gallic acid, being present in all beers, except for the "white 5 beer". It was also possible to identify phenolic compounds from the group of flavonoids, besides the presence of phenolic acids, such as coffee, vanillic and ferulic. By the Cluster analysis, it was possible to verify that the beers were grouped in 5 clusters according to their characteristics, phenolic composition and anti-radical activity, for the analysis of main components. In this way, we can conclude that the black beers were those that presented greater antioxidant capacity and greater concentration of phenolic compounds. These substances are responsible for the antioxidant potential of beers, presenting benefits to the health of those who consume it, independently to the brand, since all the beers studied presented a similar pattern of compounds (phenolics), thus being able to deprove mainly anti-atherosclerotic, antiinflammatory and anti-carcinogenic action.pt_PT
dc.subjectatividade antioxidantept_PT
dc.titleCaracterização fenólica e determinação da atividade antioxidante de cervejas portuguesaspt_PT
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