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- Influence of enzymes and technology on virgin olive oil compositionPublication . Peres, Maria de Fátima; Martins, Luísa; Dias, Suzana FerreiraThis work aims at presenting the state-of-the-art about the influence of the activity of olive endogenous enzymes, as well as of the application of adjuvants in olive oil technology, discussing their influence on the composition of virgin olive oil, especially in phenols and volatile compounds.
- Development of Cobrançosa "functional olive oils" by co-processing techniquesPublication . Marques, Madalena Pinho; Dias, Suzana Ferreira; Gouveia, Cecília; Vitorino, Conceição; Mourato, Miguel; Martins, Luísa; Peres, Maria de FátimaThe aim of this work was to develop "functional olive oils" by co-processing techniques of ‘Cobrançosa’ olives with the addition of Thymus citriodorus (TL, lemon thyme) and T. mastichina L. (TM) from organic agriculture. The “functional olive oils” were prepared by: (i) thyme addition to the olives during the unit operations of crushing or malaxation, and (ii) implementation of ultrasound before the malaxation of the olive paste.
- Changes in virgin olive oil antioxidants, polyphenol oxidase and peroxidase activities during fruit ripeningPublication . Peres, Maria de Fátima; Martins, Luísa; Mourato, Miguel; Dias, Suzana FerreiraOne of the current challenges in olive oil quality is to assure that olive antioxidante compounds are preserved in order to maintain their role on oxidative degradation protection. (...)
- 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.
- Olive oil extraction optimization of ‘Galega Vulgar’ fruits by response surface methodologyPublication . Peres, Maria de Fátima; Gouveia, Cecília; Vitorino, Conceição; Dias, Suzana FerreiraNew strategies to attain better yields, without compromising olive oil quality, are necessary in olive oil extraction. To improve virgin olive oil yield, several processing aids (talc, calcium carbonate, salt, enzymes) have already been tested. ‘Galega Vulgar’, one of the most abundant Portuguese cultivar for olive oil, usually gives difficult pastes in the malaxation step, which represents a loss of income. The present work aimed to optimize olive oil extraction, at laboratory-scale, from fruits of ‘Galega Vulgar’ cultivar in 2016 (ripening index=4; moisture content=62 % and fat content (FW) =15.8 %) with the addition of processing aids (ProZym® and natural microtalc FC8-AW), using response surface methodologies (RSM). The combined effects of the concentrations of natural microtalc (MT) and of the enzyme preparation (E) on the oil extraction yield (Y), extractability index (IE), the concentration of total phenols (TPH), chlorophyll pigments (CP), as well as on chemical quality criteria parameters of the extracted olive oil, were investigated by RSM. A Central Composite Rotatable Design (CCRD) was followed, as a function of the contents of enzyme preparation (0-0.12 %, v/w) and of natural microtalc (0-0.46 %, w/w). For ‘Galega Vulgar’ olives, the highest extractability was obtained with simultaneous addition of enzymes between 0.02 and 0.08 % (v/w) and of microtalc (0.45-0.50 %, w/w).