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  • Author or Editor: M. Sobral da Silva x
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Abstract  

Differential scanning calorimetry (DSC) was used to determine phase transitions of freeze-dried camu-camu pulp in a wide range of moisture content. Samples were equilibrated at 25°C over saturated salt solutions in order to obtain water activities (a w) between 0.11–0.90. Samples with a w>0.90 were obtained by direct water addition. At the low and intermediate moisture content range, Gordon–Taylor model was able to predict the plasticizing effect of water. In samples, with a w>0.90, the glass transition curve exhibited a discontinuity and T g was practically constant (–58.8°C), representing the glass transition temperature of the maximally concentrated phase(T g ).

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Authors: A. Ochoa, J. Fechine, J.C. Escalona, J. García, S.G. dos Santos and M. Sobral da Silva

Excoecaria lucida Sw. is an evergreen shrub widely distributed in Cuba and throughout the Caribbean region. In spite of its extended traditional use as antiasthmatic and antimicrobial by the local population, scientific reports on the species are almost nonexistent. This paper focuses on the isolation and characterization of compounds present in the crude extract of E. lucida Sw. leaves through the combined use of chromatographic and spectroscopic techniques (medium pressure liquid chromatography, thin-layer chromatography, gas chromatography, nuclear magnetic resonance 1H, and mass spectrometry). A total of 15 nonpolar substances were identified in the four main fractions obtained; some of these substances could be related with the antimicrobial properties attributed to the species.

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