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Advisor(s)
Abstract(s)
As bagas do zimbro (Juniperus communis L.) são tradicionalmente utilizadas em Trás-os-Montes como condimento em pratos de carne de caça, com o objetivo de lhes conferir um aroma e sabor particulares. São ainda utilizadas na aromatização de bebidas, tais como o gin e bebidas tradicionais. As bagas estão também descritas como tendo propriedades medicinais, com especial ênfase para as suas atividades diurética e antisséptica.
Neste trabalho estudou-se a composição química de três amostras de bagas do zimbro, uma colhida na natureza e duas adquiridas comercialmente (vendidas como condimentos alimentares em supermercados), no que respeita à sua composição nutricional (proteínas, gordura, hidratos de carbono, humidade e cinzas), ácidos gordos e compostos bioativos. A composição em ácidos gordos foi determinada por cromatografia gasosa com detetor de ionização em chama (GC-FID). A determinação do teor de fenóis totais, flavonóides totais, poder redutor e atividade antioxidante pelo método do DPPH, para os extratos metanólicos das três amostras de bagas e de uma amostra de folhas colhidas na natureza, foi realizada utilizando métodos espetrofotométricos. Por último, para uma amostra de óleo essencial de bagas do zimbro, realizaram-se ensaios de atividade antimicrobiana face a diversas bactérias gram-positivas e gram-negativas e uma levedura.
Verificou-se a ocorrência de teores superiores de fenóis totais e flavonoides nas folhas comparativamente às bagas, bem como uma superior capacidade antioxidante dos extratos de folhas, expressa em capacidade captadora do radical DPPH e poder redutor. O óleo essencial revelou capacidade de inibir o crescimento de Candida albicans, Bacillus cereus, B. subtillis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae e Enterococcus faecalis, não apresentando, contudo, atividade face a Pseudomonas aeruginosa e Proteus mirabilis nas concentrações testadas. Os resultados obtidos contribuem para o conhecimento mais aprofundado das bagas do zimbro e sugerem que o seu uso como condimento pode ser benéfico no que respeita a qualidade e segurança alimentar.
Juniper berries are traditionally used in the Northeastern region of Portugal as a condiment in game meat dishes, conferring a particular aroma and taste to these dishes. They are also used in flavouring beverages such as gin and traditional drinks. Additionally, the berries are described as having medicinal properties, with special emphasis on its diuretic and antiseptic activities. The aim of this work was to study the chemical composition of juniper berries, comparing those collected in the nature (wild) and two samples purchased commercially (sold as food flavoring/spices in supermarkets) as regard to its nutritional composition (protein, fat, carbohydrates, moisture and ash), fatty acids and bioactive compounds. Fatty acids profile was determined by gas chromatography coupled to a flame ionization detector (GC-FID). Total phenols, total flavonoids, reducing power and antioxidant activity by the DPPH radical-scavenging method was determined by using UV-Vis spectrophotometric methodologies, applied to methanolic extracts obtained for the three berries samples and one sample of juniper leaves collected in the wild. Additionally, the antimicrobial activity of a sample of essential oil from juniper berries was evaluated against a yeast and several gram-positive and gram negative bacteria. Results showed higher levels of total phenols and flavonoids in the leaves compared to the berries, as well as a superior antioxidant capacity of leaves extracts, expressed in DPPH radical scavenging capacity and reducing power. The essential oil has shown ability to inhibit the growth of C. albicans, Bacillus cereus, B. subtillis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Enterococcus faecalis, however, not showing activity at the tested concentrations against Pseudomonas aeruginosa and Proteus mirabilis. The results of this work contribute to increase the knowledge regarding juniper berries composition and suggest that its use as a condiment in food can be beneficial as regards food quality and safety.
Juniper berries are traditionally used in the Northeastern region of Portugal as a condiment in game meat dishes, conferring a particular aroma and taste to these dishes. They are also used in flavouring beverages such as gin and traditional drinks. Additionally, the berries are described as having medicinal properties, with special emphasis on its diuretic and antiseptic activities. The aim of this work was to study the chemical composition of juniper berries, comparing those collected in the nature (wild) and two samples purchased commercially (sold as food flavoring/spices in supermarkets) as regard to its nutritional composition (protein, fat, carbohydrates, moisture and ash), fatty acids and bioactive compounds. Fatty acids profile was determined by gas chromatography coupled to a flame ionization detector (GC-FID). Total phenols, total flavonoids, reducing power and antioxidant activity by the DPPH radical-scavenging method was determined by using UV-Vis spectrophotometric methodologies, applied to methanolic extracts obtained for the three berries samples and one sample of juniper leaves collected in the wild. Additionally, the antimicrobial activity of a sample of essential oil from juniper berries was evaluated against a yeast and several gram-positive and gram negative bacteria. Results showed higher levels of total phenols and flavonoids in the leaves compared to the berries, as well as a superior antioxidant capacity of leaves extracts, expressed in DPPH radical scavenging capacity and reducing power. The essential oil has shown ability to inhibit the growth of C. albicans, Bacillus cereus, B. subtillis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Enterococcus faecalis, however, not showing activity at the tested concentrations against Pseudomonas aeruginosa and Proteus mirabilis. The results of this work contribute to increase the knowledge regarding juniper berries composition and suggest that its use as a condiment in food can be beneficial as regards food quality and safety.
Description
Keywords
Bagas do zimbro Condimento alimentar Atividade antioxidante Atividade antimicrobiana Fenóis Flavonoides