Browsing by Author "Almeida, Domingos P. F."
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- Antioxidant properties and fruit quality during long-term storage of “rocha” pear: effects of maturity and storage conditionsPublication . Silva, Filipe J. P.; Gomes, Maria Helena; Fidalgo, Fernanda; Rodrigues, José A.; Almeida, Domingos P. F.Free radical scavenging activity and the content of ascorbic acid and glutathione were investigated during long-term storage of the pear (Pyrus communis L. ‘Rocha’) fruit harvested at different maturity stages, stored in air or under controlled atmosphere and subjected to postharvest treatments with diphenylamine (DPA) and 1-methylcyclopropene (1-MCP). Harvest maturity had a significant effect on storage disorders, fruit firmness, soluble solids content and acidity. Differences in ascorbate content and free radical scavenging activity at harvest did not persist during storage. Controlled atmosphere and DPA strongly reduced the incidence and severity of browning disorders and superficial scald, whereas 1-MCP provided the most effective control. Neither DPA nor 1-MCP affected the free radical scavenging activity
- Auditing functional phytochemicals during fruit processingPublication . Oliveira, A.; Pintado, M.; Almeida, Domingos P. F.
- Autolysis of cell walls from polygalacturonase-antisense tomato fruit in simulated apoplastic solutionsPublication . Almeida, Domingos P. F.; Huber, Donald J.Autolysis of cell walls from polygalacturonase (PG)-antisense tomato fruit was studied in a conventional buffer designed to maximize the catalytic activity of PG (30 mM sodium acetate, 150 mM NaCl, pH 4.5), and in solutions mimicking the pH and mineral composition of the fruit apoplast at the mature-green and ripe stages. Autolytic release of uronic acids was very limited under simulated apoplastic conditions compared with the conventional buffer, but minimal differences in the release of reducing groups were observed among the incubation conditions. Autolytic release of uronic acids from active walls was lower than solubilization from enzymically inactive walls. Uronic acids that remained ionically bound to the cell walls during autolysis were subsequently extracted and analyzed by size exclusion chromatography. The elution profiles of ionically bound uronic acids from cell walls incubated under optimal conditions were similar for all ripening stages. In solutions mimicking the pH and mineral composition of the apoplast of mature-green and ripe fruit, uronic acids extracted from pink and ripe fruit cell walls showed a decrease in average molecular mass compared with polymers from mature-green cell walls. The results suggest that the composition of the incubation solution exert strong influence on PG-independent cell wall autolysis and that enzymically active walls restrain PG-independent pectin solubilization.
- Bioactive phytochemicals in apple cultivars from the Portuguese protected geographical indication “Maçã de Alcobaça”: basis for market segmentationPublication . Almeida, Domingos P. F.; Gião, Maria S.; Pintado, Manuela; Gomes, Maria HelenaPhytochemical composition and antioxidant activity of eight apple (Malus domestica) cultivars (“Casa Nova,” “Fuji,” “Golden Delicious,” “Granny Smith,” “Jonagored,” “Reinette Grise,” “Royal Gala,” and “Starking”) from the “Maçã de Alcobaça” protected geographic indication, Portugal, were characterized to support market segmentation based on phytochemical content. Total phenolics, flavonoids, and anthocyanin contents, individual polyphenols and antioxidant activity were assessed in the flesh and skin of fruit at the ripe stage. A market segmentation of apple cultivars based on these bioactive phytochemicals is proposed. Fruit eaten with the peel can be segmented in three classes: (1) the flavonoid-rich “Starking,” “Reineta,” “Galaxy,” “Casa Nova,” Jonagored;” (2) the quercetin-rich “Fuji,” “Galaxy,” “Casa Nova;” and (3) flavonol and procyanidin-rich “Starking,” “Reinette,” “Jonagored,” “Casa Nova.” When apples were peeled before consumption, two phytochemical classes were proposed: (1) the flavonoid-rich “Reinette” and “Casa Nova,” and the (2) chlorogenic acid-rich “Reineta,” “Casa Nova,” and “Starking.”
- Breeding cut roses for better keeping quality: first stepsPublication . Fanourakis, D.; Carvalho, D.R.A; Gitonga, V.; Heusden, A.W. van; Almeida, Domingos P. F.; Heuvelink, E.; Carvalho, Susana M.P.
- Changes in phenolic compounds during storage of pasteurized strawberryPublication . Oliveira, Ana; Almeida, Domingos P. F.; Pintado, ManuelaThis study aimed to establish mathematical models to describe changes in phenolics of pasteurized strawberry (Fragaria ×ananassa Duch.) during storage at 23 °C for 90 days. Freshly cut strawberries cubes were pasteurized for 5 min in a water bath at 90 °C following a heating time of 15 min. Antioxidant activity, total phenolics, total anthocyanins, and individual phenolic compounds were assessed immediately before or after pasteurization and at regular time intervals during storage. The results indicated that (1) pasteurization did not affect (P <0.05) the concentrations of total phenolics or total anthocyanins, but significantly reduced the concentrations of quercetin-3-rutinoside, kaempferol, and cyanidin-3- glucoside, and increased the concentrations of (+)-catechin, (−)-epicatechin, epigallocatechin gallate, quercetin-3- galactoside, and ellagic acid; (2) changes in antioxidant capacity, total anthocyanin, and individual compounds during storage were described by a pseudo-first-order model with the exception of total phenolic and specifically kaempferol and ellagic acid which followed zero-order kinetic models. Pelargonidin-3- glucoside degraded at the highest rate (k =0.07 day−1), followed by ellagic acid (k =0.004 day−1) and kaempferol (k = 0.003 day−1). The rate constants can be used to predict phytochemical changes in strawberry products during storage.
- Controlo da altura de plantas ornamentais: alternativas sustentáveis aos reguladores de crescimentoPublication . Carvalho, Susana M. P.; Almeida, Domingos P. F.; Heuvelink, EpA necessidade de encontrar estratégias sustentáveis eficazes no controlo da altura da planta é actualmente um grande desafio que se coloca à horticultura ornamental protegida. Este estudo teve como objectivo: (1) analisar a informação disponível acerca dos factores que afectam a altura das plantas; (2) compreender os mecanismos fisiológicos envolvidos no processo de alongamento do caule; (3) definir alternativas sustentáveis para produzir plantas compactas, reduzindo ao mínimo a aplicação de „reguladores químicos de crescimento‟. Concluiu-se que manter uma temperatura nocturna superior à temperatura diurna (DIF negativa ou tratamento DROP) ou a alteração do espectro luminoso (elevado rácio vermelho/vermelho-longínquo) apresentam um forte potencial como métodos não químicos no controlo da altura de várias espécies de plantas ornamentais. Oaumento do rácio vermelho/vermelho-longínquo, poderáser efectuado de diferentes modos incluindo a utilização defilmes fotosselectivose/ourecorrendoa um conjunto de medidas facilmente aplicáveis tais como:(i) evitar densidades de plantação muito elevadas; (ii) utilização de luz suplementar com elevado rácio vermelho/vermelho-longínquo (ex. lâmpadas de assimilação em substituição de lâmpadas incandescentes); (iii) evitar a exposição das plantas à radiação do crepúsculo (devido à diminuição natural do rácio vermelho/vermelho-longínquo). O stress mecânico é também uma medida eficaz para a manutenção de plantas compactas em determinadas espécies. Paralelamente, o recurso ao Melhoramento de plantas no sentido de seleccionar cultivares ananicantes poderá ser bastante promissor. Porém, na maioria dos casos, não será uma medida única que permitirá a obtenção de plantas compactas, mas a combinação de várias estratégias.
- Controlo da altura de plantas ornamentais: alternativas sustentáveis aos reguladores de crescimentoPublication . Carvalho, Susana M. P.; Almeida, Domingos P. F.; Heuvelink, Ep
- Controlo da altura de plantas ornamentais: alternativas sustentáveis aos reguladores de crescimentoPublication . Carvalho, Susana M. P.; Almeida, Domingos P. F.; Heuvelink, Ep
- Desenvolvimento de uma metodologia de auditoria nutricional ao processamento do morangoPublication . Oliveira, Ana; Pintado, M. E.; Almeida, Domingos P. F.