Loading...
Publication
Efeito da presença de gafa na azeitona nos compostos bioativos do azeite
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.43 MB | Adobe PDF |
Authors
Abstract(s)
Uma das doenças fúngicas mais relevantes da oliveira em Portugal é a antracnose, também conhecida por "gafa", que tem consequências negativas na quantidade e na qualidade do azeite. O presente estudo incide sobre o efeito da presença de gafa nos frutos das cultivares ‘Galega Vulgar’ e 'Cobrançosa', no teor de compostos bioativos, nomeadamente na composição em fenóis, hidroxitirosol (Htyr) e seus derivados (alegação de saúde) de azeites extraídos de azeitonas colhidas em outubro e novembro em três anos consecutivos (2019-2021). Os frutos foram colhidos em Castelo Branco em olivais de sequeiro sem tratamentos fitossanitários. Imediatamente após a colheita, o azeite foi extraído num sistema Abencor. Os critérios de qualidade foram avaliados por espetroscopia NIR, os fenóis totais e os pigmentos por espectroscopia VIS. O perfil fenólico foi avaliado por HPLC-UV, os derivados totais de Hyt e tirosol (Tyr) por HPLC-DAD. Os resultados dos critérios de qualidade mostram que os azeites Galega extraídos de azeitonas num estado avançado de maturação (IM > 5) e com maior incidência de gafa apresentam não conformidade para as categorias Azeite Virgem Extra (AVE) e Azeite Virgem (AV), pela acidez elevada e notas sensoriais negativas acompanhadas de um quase desaparecimento de oleaceína. Pelo contrário, nos azeites Cobrançosa extraídos de frutos com elevada incidência de gafa, não foram observados defeitos sensoriais. Apesar da diminuição de todos os atributos positivos associados à cultivar, como os teores de oleaceína e oleocantal, os critérios de qualidade mantiveram-se em conformidade com a categoria AVE. O teor total de Htyr e Tyr (> 5,42) permite a utilização da alegação de saúde no rótulo dos azeites Cobrançosa. Nos azeites Galega, apenas os das duas primeiras colheitas de 2019 contêm teores suficientes para a alegação. Assim, a presença de gafa nas azeitonas pode comprometer a classificação de AVE e AV, especialmente em cultivares suscetíveis à doença.
Abstract_ One of the most relevant fungal diseases of the olive tree in Portugal is anthracnose, also known as 'gafa', which has negative effects on the yield and quality of the olive oil. The present study focuses on the effect of olive anthracnose on the content of bioactive compounds, namely on the composition in phenols, namely hydroxytyrosol (Htyr) and its derivatives (health claim) in olive oils extracted from 'Galega' and 'Cobrançosa'cultivar olive, harvested in October and November of three consecutive years (2019-2021). The olives were harvested in Castelo Branco (Center of Portugal) in organic rainfed orchards and immediately extracted in an Abencor system. The quality criteria were evaluated by NIR spectroscopy and total phenols and pigments by VIS spectroscopy. Phenolic profile was evaluated by HPLC-UV, total Htyr and tyrosol (Tyr) derivatives by HPLC-DAD. The results of the quality criteria show that Galega olive oils extracted from olives in advanced ripening stage (RI > 5) and with a high anthracnose incidence show no conformity for the Extra Virgin Olive Oil (EVOO) and Virgin Olive Oil (VOO) categories, with high acidity values and negative sensory notes accompanied by disappearance of oleacein. Conversely, Cobrançosa olive oils extracted from fruit with high anthracnose incidence, no sensory defects were observed. However, despite a decrease in all the positive attributes associated with the cultivar, namely in oleacein and oleocanthal contents, quality criteria were still in accordance with the EVOO category. The total Htyr and Tyr content (> 5.42) allows the use of the health claim on the label of the Cobrançosa olive oils. In Galega olive oils, only those of the first two harvests of 2019 contained sufficient contents to fulfill the health claim. Thus, the presence of anthracnose in the olives may compromise the EVOO and VOO classification, especially in cultivars susceptible to the disease.
Abstract_ One of the most relevant fungal diseases of the olive tree in Portugal is anthracnose, also known as 'gafa', which has negative effects on the yield and quality of the olive oil. The present study focuses on the effect of olive anthracnose on the content of bioactive compounds, namely on the composition in phenols, namely hydroxytyrosol (Htyr) and its derivatives (health claim) in olive oils extracted from 'Galega' and 'Cobrançosa'cultivar olive, harvested in October and November of three consecutive years (2019-2021). The olives were harvested in Castelo Branco (Center of Portugal) in organic rainfed orchards and immediately extracted in an Abencor system. The quality criteria were evaluated by NIR spectroscopy and total phenols and pigments by VIS spectroscopy. Phenolic profile was evaluated by HPLC-UV, total Htyr and tyrosol (Tyr) derivatives by HPLC-DAD. The results of the quality criteria show that Galega olive oils extracted from olives in advanced ripening stage (RI > 5) and with a high anthracnose incidence show no conformity for the Extra Virgin Olive Oil (EVOO) and Virgin Olive Oil (VOO) categories, with high acidity values and negative sensory notes accompanied by disappearance of oleacein. Conversely, Cobrançosa olive oils extracted from fruit with high anthracnose incidence, no sensory defects were observed. However, despite a decrease in all the positive attributes associated with the cultivar, namely in oleacein and oleocanthal contents, quality criteria were still in accordance with the EVOO category. The total Htyr and Tyr content (> 5.42) allows the use of the health claim on the label of the Cobrançosa olive oils. In Galega olive oils, only those of the first two harvests of 2019 contained sufficient contents to fulfill the health claim. Thus, the presence of anthracnose in the olives may compromise the EVOO and VOO classification, especially in cultivars susceptible to the disease.
Description
Dissertação apresentada à Escola Superior Agrária de Castelo Branco do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Engenharia Agronómica.
Keywords
Colletotrichum spp. Alegação de saúde Compostos bioativos Maturação Health claim Bioactive compounds Ripening
Citation
GOUVEIA, Cecília Maria Marcelo da Silva (2023) - Efeito da presença de gafa na azeitona nos compostos bioativos do azeite. Castelo Branco : IPCB. ESA. 74 p.