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Advisor(s)
Abstract(s)
Nos últimos anos, o consumo de frutas e vegetais tem sido recomendado pela Organização Mundial de Saúde (OMS), numa perspectiva de prevenção de diversas patologias, tais como o cancro, a osteoporose e doenças cardiometabólicas e degenerativas. Os benefícios destes alimentos para a saúde humana estão associados à presença de compostos com actividade antioxidante capazes de minimizar alterações celulares induzidas por espécies reactivas de oxigénio e azoto. O presente trabalho tem como principais objectivos determinar o teor total de polifenóis e consequentemente a capacidade antioxidante dos brócolos e canónigos, avaliando paralelamente a influência das condições de extracção através de variadas técnicas espectrofotométricas; e ainda caracterizar a composição fenólica dos canónigos após separação por cromatografia líquida (HPLC-DAD-ESI/MS/MS). Os resultados mostram que os canónigos possuem um teor de polifenóis totais cerca de 3 vezes superior em relação aos bróculos, bem como 4 a 22 vezes maior capacidade antioxidante. O solvente mais eficaz na extracção dos polifenóis em ambos os vegetais foi o metanol. Foram identificados cinco compostos fenólicos, onde se destaca o ácido clorogénico como principal constituinte da matriz dos canónigos, com 168+-9 mg ACG/100 g peso fresco(PF).
ABSTRACT: In last years the consumption of fruits and vegetables has been recommended by world health organization (WHO) trying to prevent several diseases such as, cancer, osteoporosis, cardiomethabolic and degenerative diseades. The benefits of these foods for human health are associated with the presence of compounds with antioxidant activity capable of minimizing cellular changes induced by reactive oxygen species and nitrogen. The present work's main objectives were the total content of plyphenols determination and consequently the antioxidant capacity of broccoli and lamb's lettuce, evaluating the influence of the extraction conditions by spectrophotometric techniques; and characterize the phenolic composition of lamb's lettuce after separation by liquid chromatography (HPLC-DAD-ESI/MS/MS). The results indicate that lamb's lettuce contains about 3-fold higher amount of total polyphenols compared to broccoli, as well as higher antioxidant activity, up to 22-fold. The most efficient solvent extraction of polyphenols in both plants was methanol. A total of five compounds were identified and the main phenolic compound found was chlorogenic acid with a content of 168+-9 mg CGA/100 g fresh weight (FW).
ABSTRACT: In last years the consumption of fruits and vegetables has been recommended by world health organization (WHO) trying to prevent several diseases such as, cancer, osteoporosis, cardiomethabolic and degenerative diseades. The benefits of these foods for human health are associated with the presence of compounds with antioxidant activity capable of minimizing cellular changes induced by reactive oxygen species and nitrogen. The present work's main objectives were the total content of plyphenols determination and consequently the antioxidant capacity of broccoli and lamb's lettuce, evaluating the influence of the extraction conditions by spectrophotometric techniques; and characterize the phenolic composition of lamb's lettuce after separation by liquid chromatography (HPLC-DAD-ESI/MS/MS). The results indicate that lamb's lettuce contains about 3-fold higher amount of total polyphenols compared to broccoli, as well as higher antioxidant activity, up to 22-fold. The most efficient solvent extraction of polyphenols in both plants was methanol. A total of five compounds were identified and the main phenolic compound found was chlorogenic acid with a content of 168+-9 mg CGA/100 g fresh weight (FW).
Description
Dissertação de Mestrado em Qualidade e Tecnologia Alimentar
Keywords
Valerianella Locusta Brássica Antioxidante Composto fenólico Polifenol Cromatografia líquida Espectrometria de massa Espectrofotometria Antioxidant activity Polyphenol Phenolic composition Chromatography HPLC
Citation
Publisher
Instituto Politécnico de Viseu. Escola Superior Agrária