Navegando por Autor "Leitão, António Eduardo"

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    Low temperature impact on photosynthetic parameters of coffee genotypes
    (Empresa Brasileira de Pesquisa Agropecuária - Embrapa, 2009-11) Partelli, Fábio Luiz; Vieira, Henrique Duarte; Viana, Alexandre Pio; Batista‐Santos, Paula; Rodrigues, Ana Paula; Leitão, António Eduardo; Ramalho, osé Cochicho
    The objective of this work was to evaluate photoprotective mechanisms related to low positive temperatures in Coffea canephora (Conilon clones 02 and 153) and C. arabica ('Catucaí' IPR 102) genotypes, involved in cold temperature tolerance. To accomplish this, one‐year‐old plants were successively submitted to: temperature decrease of 0.5oC day ‐1 , from 25/20oC to 13/8oC; a three‐day chilling cycle at 13/4oC; and a recovery period of 14 days (25/20oC). During the experiment, leaf gas exchange, chlorophyll a fluorescence and leaf photosynthetic pigment content were evaluated. Total activity of ribulose‐1,5‐bisphosphate carboxylase/ oxygenase (Rubisco) and ribulose‐5‐phosphate kinase (Ru5PK) were quantified to measure the activity of photosynthesis key enzymes. All genotypes showed low temperature sensitivity, but displayed diverse cold impact and recovery capabilities regarding the photosynthetic‐related parameters studied. Catucaí IPR 102 cultivar showed better ability to cope with cold stress than the Conilon clones, especially Conilon 02, and had full recovery of leaf gas exchange, fluorescence parameters, enzymatic activity, and higher contents of the photoprotective pigments zeaxanthin and lutein.
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    Use of colour parameters for roasted coffee assessment
    (Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2012-07) Bicho, Natalina Cavaco; Leitão, António Eduardo; Ramalho, José Cochicho; Lidon, Fernando Cebola
    Fast and non-destructive indicators were evaluated as tools to measure the technological quality of Arabica and Robusta coffee. Accordingly, considering the roasting intensity in highly valuable commercial samples, volume, mass, apparent density, moisture, total ash, ash insoluble in hydrochloric acid, and ether extract were characterized. The chromatic parameters L*, C*, H° were measured using illuminants D 65 and C. It was found that in roasted coffee beans, the parameters L∗, C*, H°, and coordinate b* had an antagonist interaction due to an increase in the roasting intensity, whereas after milling, only L* and H° decreased progressively. Considering that the parameters L* and H° followed similar patterns using both illuminants, D 65 and C, it can be concluded that they are appropriate to evaluate coffee colour changes during roasting, enabling a relationship with coffee quality.