Percorrer por autor "Dandlen, S."
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- Essential oils of flowers of Citrus sinensis and Citrus clementina cultivated in Algarve, PortugalPublication . Miguel, Maria Graça; Dandlen, S.; Figueiredo, A. C.; Barroso, J. G.; Pedro, L. G.; Duarte, Amílcar; Faísca, J.The essential oils, isolated by hydrodistillation, from the flowers of different cultivars of Citrus sinensis (L.) Osbeck (Cs) and Citrus clementina Hort. Ex Tan. (Cc) collected at different harvesting times, were analyzed by GC and GC-MS. All the samples studied afforded yellowish oil which yields ranged from 0.05 to 0.08 % (v/w). The monoterpene fraction dominated both oils (66-91%), being the monoterpene hydrocarbons the main components of this fraction (45-69%). Sabinene (31-48%), linalool (15-32%) and limonene (4-10%) dominated both Cs and Cc oils. trans-Nerolidol was the major sesquiterpene component, attaining 3-10%. Cluster analysis of the essential oil composition from the twelve samples studied, confirmed a major chemical homogeneity (Scorr>0.95) despite the fact of having used different periods of hydrodistillation, different harvesting times and being flowers of two different Citrus species.
- Influence of citric acid, ascorbic acid and calcium lactate applications on the shelf life of minimally processed horticultural productsPublication . Rodrigues, D.; Miguel, Maria Graça; Dandlen, S.; Nunes, S.; Antunes, Maria DulceThe market share of minimally processed fruits and vegetables has continuously increased in the past years due to consumer life style. These products have high expectations regarding quality and shelf-life. The objective of the present work was to evaluate the effect of additives applied externally after cutting in fresh-cut kiwifruit, pears, strawberries, tomatoes, and peppers. Fruit were washed in water, cut longitudinally in quarters and dipped in solutions of 2% citric acid, 2% ascorbic acid or 2% calcium lactate. Subsequently, fruit were packed in plastic trays, covered with 15 mu m thick polyethylene film and stored at 4 degrees C for 9 d. At intervals of 0, 3, 6 and 9 d, measurements of firmness and total phenolics content were performed. Calcium lactate was efficient in maintaining firmness in most fresh-cut fruit. Total phenolics content were higher in kiwifruit, strawberries and peppers than in pears and tomatoes. Ascorbic acid was the most efficient dip to maintain or increase the total phenolics content of the fresh-cut fruit studied.
- Root ferric chelate reductase is regulated by iron and copper in straberry plantsPublication . Pestana, M.; Correia, P. J.; Saavedra, Teresa; Gama, Florinda; Dandlen, S.; Nolasco, Gustavo; Varennes, Amarilis deIn the present experiment, we studied the interaction between copper (Cu) and iron (Fe) in strawberry plants grown in nutrient solutions containing different concentrations of Fe. Plants grown in the absence of iron (Fe0) had the characteristic symptoms of Fe deficiency, with smaller chlorotic leaves, less biomass, acidification of the nutrient solution, and roots that were smaller and less ramified, while no symptoms of Fe deficiency were observed in plants grown with Fe. A greater amount of Cu was found in roots of chlorotic plants than in those grown with Fe, while plants grown with 20M of Fe (Fe20) in the nutrient solution had a greater amount of Fe compared with plants from the other treatments. Chlorotic plants (Fe0) and plants grown with the greatest level of Fe (Fe20) had a greater root ferric chelate reductase (FC-R; EC 1.16.1.17) activity compared with the other treatments with 5 or 10M Fe in the nutrient solution. The same pattern was obtained for relative FC-R mRNA concentration and for the sum of Fe and Cu contents in shoots (leaves plus crowns). The DNA obtained from amplification of the FC-R mRNA was cloned and several of the inserts analysed by single strand confirmation polymorphism (SSCP). Although there were different SSCP patterns in the Fe20 treatment, all the inserts that were sequenced were very similar, excluding the hypothesis of more than one FC-R mRNA species being present. The results suggest that Cu as well as Fe is involved in FC-R expression and activity, although the mechanism involved in this regulation is unknown so far. Both small contents of Fe and Cu in plants led to an over-expression of the FC-R gene and enhanced FC-R activity in strawberry roots.