Navegando por Autor "VIEIRA, Marcos Ribeiro da Silva"

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Acesso aberto (Open Access)
Correlações entre compostos fenólicos e atividade antioxidante em casca e polpa de variedades de uva de mesa
(Instituto de Tecnologia de Alimentos, 2018) SOUZA, Angela Vacaro de; VIEIRA, Marcos Ribeiro da Silva; PUTTI, Fernando Ferrari
Grapes are considered a major source of phenolic compounds when compared to other vegetables, but the great diversity amongst the cultivars results in fruits with different characteristics of taste and colour, which is certainly associated with the polyphenol content and profile. Skins and pulps of ripe samples of “Itália”, “Brasil”, “Rubi”, “Thompson” and “Niagara Rosada” grapes from the Campinas and Jundiaí regions - SP state - Brazil, were studied with the objective of evaluating the antioxidant activity, enzymatic activities of peroxidase and polyphenoloxidase, phenolic compounds and ascorbic acid. In order to verify correlations between the skins and pulps of the varieties and the characteristics studied, Pearson’s correlation, the generalized distance of Mahalanobis (D2) and finally the grouping of the different responses using the multivariate analysis, were carried out. It was verified that the skins of the grapes analysed had a positive correlation with the phenolic compounds, polyphenoloxidase activity and ascorbic acid content, except for “Niagara Rosada”, showing higher levels for these evaluations. There was no correlation between the antioxidant activity and the other analyzes. This shows that for the majority of the varieties evaluated, the skins are a great source of these compounds
Acesso aberto (Open Access)
Ethanol and citric acid improve longevity in Gerbera cv. Mistique
(Universidade Federal do Pará, 2019-08) MAIA, Rúbia Kécia Marins; SILVA, Edivan Amaro da; ALVES, Rafael Mateus; MORAIS, Maria Aparecida dos Santos; VIEIRA, Marcos Ribeiro da Silva; SILVA, Luzia Ferreira da; FONSECA, Kelem Silva; SIMÔES, Adriano do Nascimento; SIMÔES, Raquel Ferraz Jardim
Ethanol and citric acid can increase longevity in some cut flowers. However, its use must be extremely careful, with application methods and specific concentrations for each type of cut flower. Thus, the objective was to examine the physico-chemical and physiological changes in Gerbera cv. Mistique cut flowers treated with ethanol (Et) and/or citric acid (CA). Stem were selected and standardized to a length of 35 cm and maintained at 20 ± 2 °C and RH 65 ± 2%, under continuous lighting. The flowers were subjected to two application methods (pulsing for 48 h and maintenance), using different concentrations of Et (4%, 6%, and 8%) and/or CA (100 and 200 mg L-1) and distilled water (control). A visual assessment and analyses of longevity, stem bending, fresh mass, relative water content, electrolyte leakage, and peroxidase and polyphenol oxidase enzyme activities were performed at every two days. The Et (4%) + CA (100 mg L-1) solution provided the greatest longevity, regardless of the application method. These results were the basis for a third experiment, in which the stems were immersed in pulsing solutions of Et (4%) and/or CA (100 mg L-1) and distilled water (control). The Gerbera flowers under Et + CA solution showed lower fresh mass loss and electrolyte leakage, higher relative water content and a slower increase in polyphenol oxidase and peroxidase activities. This allowed for delayed stem bending and better appearance, resulting in greater longevity compared to the other solutions.