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Advisor(s)
Abstract(s)
A região do Douro é tradicionalmente conhecida como grande produtora de vinho do Porto e de vinhos de qualidade. Nos últimos anos, alguns dos produtores, no sentido de aproveitar o marketing associado à região, começaram a embalar azeites produzidos nessa área geográfica. Neste sentido, e uma vez que não existia até ao momento nenhuma referência à composição dos azeites produzidos no vale do Douro, foi objetivo deste trabalho proceder a uma caraterização preliminar em termos de qualidade, composição química e atividade antioxidante de diferentes amostras de azeites produzidos nesta região.
Os resultados indicam que as diferentes amostras avaliadas são de excelente qualidade, em que os valores dos parâmetros de qualidade (acidez, índice de peróxido e coeficientes de extinção específica no ultravioleta) se encontravam muito abaixo dos máximos estabelecidos para a categoria de azeite virgem extra.
A composição em ácidos gordos e esteróis, ainda que com grande variação entre amostras, encontram-se dentro das gamas de valores normais para azeite. Por sua vez, o teor em tocoferóis apresenta valores muito superiores aos azeites produzidos na região de Trás-os-Montes, o que pode ser um fator distintivo caraterístico dos azeites do Douro. Foi também observado uma elevada capacidade de sequestro de radicais de DPPH, indicativo do elevado valor biológico destes azeites. Os resultados obtidos, ainda que preliminares, são um passo importante para a caraterização dos azeites da região, no entanto dever-se-á proceder à análise de um maior número de amostras, provenientes de toda a região e de anos de produção distintos para uma melhor caraterização dos azeites do Vale do Douro.
The Douro region is traditionally known as a major producer of Port wine and quality wines. In recent years, some of the producers, in order to take advantage of the marketing associated with the region began to pack olive oils produced in that geographical area. In this sense, and since there was so far no reference to the composition of oils produced in the Douro valley, the aim of this study was to undertake a preliminary characterization in terms of quality, chemical composition and antioxidant activity of different samples of olive oils produced in this region. The results indicated that the different samples tested were of excellent quality, in which the values of the quality parameters (acidity, peroxide value and coefficients of specific extinction at ultraviolet) were far below the maximum limits for the category of extra virgin olive oil. The composition of fatty acids and sterols, even with high variation between samples, are within the normal ranges of values for olive oil. In turn, the content of tocopherols showed much higher values than those of olive oils produced in the region of Trás-os-Montes, which can be a characteristic distinguishing factor of the Douro olive oils. It was also observed a high sequestration capacity of DPPH radical, indicative of high biological value of these oils. The results, although preliminary, are an important step for the characterization of olive oils of the region, however it will should proceed to analysis of a larger number of samples from across the region and years of production for a better characterization of olive oils from the Douro Valley.
The Douro region is traditionally known as a major producer of Port wine and quality wines. In recent years, some of the producers, in order to take advantage of the marketing associated with the region began to pack olive oils produced in that geographical area. In this sense, and since there was so far no reference to the composition of oils produced in the Douro valley, the aim of this study was to undertake a preliminary characterization in terms of quality, chemical composition and antioxidant activity of different samples of olive oils produced in this region. The results indicated that the different samples tested were of excellent quality, in which the values of the quality parameters (acidity, peroxide value and coefficients of specific extinction at ultraviolet) were far below the maximum limits for the category of extra virgin olive oil. The composition of fatty acids and sterols, even with high variation between samples, are within the normal ranges of values for olive oil. In turn, the content of tocopherols showed much higher values than those of olive oils produced in the region of Trás-os-Montes, which can be a characteristic distinguishing factor of the Douro olive oils. It was also observed a high sequestration capacity of DPPH radical, indicative of high biological value of these oils. The results, although preliminary, are an important step for the characterization of olive oils of the region, however it will should proceed to analysis of a larger number of samples from across the region and years of production for a better characterization of olive oils from the Douro Valley.
Description
Keywords
Azeite Região do Douro Qualidade Ácidos gordos Esteróis Tocoferóis