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- How the “Olive Oil Polyphenols” health claim depends on anthracnose and olive fly on fruitsPublication . Peres, Maria de Fátima; Gouveia, Cecília; Vitorino, Conceição; Oliveira, Helena; Dias, Suzana FerreiraOlive anthracnose, caused by Colletotrichum fungi, and the olive fruit fly Bactrocera olea are, respectively, the most important fungal disease and pest affecting olive fruits worldwide, leading to detrimental effects on the yield and quality of fruits and olive oil. This study focuses on the content of hydroxytyrosol (HYT) and its derivatives (the “olive oil polyphenols” health claim) in olive oils extracted from fruits of ‘Galega Vulgar’ and ‘Cobrançosa’ cultivars, naturally affected by olive anthracnose and olive fly. The olives, with different damage levels, were harvested from organic rainfed orchards, located in the center of Portugal, at four harvest times over three years. Galega oils extracted from olives with a higher anthracnose and olive fly incidence showed no conformity for the extra virgin olive oil (EVOO) and virgin olive oil (VOO) categories, presenting high acidity and negative sensory notes accompanied by the disappearance of oleacein. Conversely, no sensory defects were observed in Cobrançosa oils, regardless of disease and pest incidence levels, and quality criteria were still in accordance with the EVOO category. The total HYT and tyrosol (TYR) content (>5 mg/20 g) allows for the use of the “olive oil polyphenols” health claim on the label of all the analyzed Cobrançosa olive oils.
- Olive oils from fruits infected with different anthracnose pathogens show sensory defects earlier than chemical degradationPublication . Talhinhas, Pedro; Afonso, Hugo; Alegre, Helena; Oliveira, Helena; Dias, Suzana FerreiraAnthracnose is the most important disease of olives responsible for olive oil depreciation. The aim of this study is to compare the negative effects of the most common olive anthracnose pathogens in Portugal, Colletotrichum nymphaeae, C. godetiae, or C. acutatum, on oil extracted from fruits of the most cultivated Portuguese olive cultivars, ‘Galega Vulgar’ and ‘Cobrançosa’. Healthy fruits (ripening index 3.5) were inoculated, incubated, and sampled over 14 days post-inoculation (d.p.i.) for symptom assessment and oil extraction. Virgin olive oil (VOO) was characterised by quality criteria parameters (acidity, peroxide value, UV absorbances, organoleptic assessment, fatty acid ethyl esters (FAEE)), total phenols (TPH), main fatty acids, and waxes compositions. Galega Vulgar fruits were more susceptible to anthracnose than Cobrançosa fruits. Colletotrichum nymphaeae was equally highly virulent for both cultivars, while C. godetiae was less virulent especially in Cobrançosa. VOO acidity increased reached 5% in Galega oils and 2% in Cobrançosa oils from fruits infected with C. nymphaeae or C. acutatum at 14 d.p.i. FAEE were higher than the legal limit for extra VOO in Galega oils from fruits at 7 d.p.i. with C. nymphaeae or C. acutatum, or 11 d.p.i. with C. godetiae. TPH decreased through the experiments with all the inoculated fungi. The musty sensory defect was detected in Galega and Cobrançosa VOO from fruits inoculated with C. nymphaeae or C. acutatum at 3 or 7 d.p.i. earlier than chemical degradation, respectively. The degradation levels of olive oils depended on the Colletotrichum species and olive cultivar.
- Influence of olive anthracnose and olive fruit fly on bioactive compounds of Cobrançosa olive oilsPublication . Gouveia, Cecília; Dias, Suzana Ferreira; Vitorino, Conceição; Oliveira, Helena; Peres, Maria de FátimaPhenolic compounds are the most important bioactive compounds in olives and since 2012 a health claim can be declared for the olive oil if it contains more than 5 mg of hydroxytyrosol (Hyt) and its derivatives per 20 g of oil1. In turn, β-carotene is a precursor of vitamin A that essentially functions in many biological processes including vision. However, the presence of bioactive compounds in olive oils depends on cultivar, agro-ecological conditions, harvest time, post-harvest, extraction technology and storage.