RESUMEN
A non-ionic water-soluble galactomannan, isolated from the seed endosperm of Crotalaria mucronata Desv., may be an ideal thickener to increase food viscosity. The present study hypothesized that the viscous property of Crotalaria galactomannan may be associated with its spatial structure. Therefore, the structure of Crotalaria galactomannan was elucidated using an atomic force microscope. The results of the present study demonstrated that the polysaccharide consisted of a Dmannose backbone with Dgalactose branches, and the Dmannose/Dgalactose ratio was 2.375:1. In the threedimensional structure of Crotalaria galactomannan, the helix was a common secondary structure, containing numerous ring structures of different sizes. In addition, multiple helixes may link together via hydrogen bonding and van der Waals forces, forming aggregations with small rings or spiral windings. The results of the present study indicated that the multiplebranching construction of Crotalaria galactomannan may underlie its viscosityenhancing properties in the water phase.
Asunto(s)
Crotalaria/química , Galactosa/química , Mananos/química , Manosa/química , Semillas/química , Conformación de Carbohidratos , Enlace de Hidrógeno , Mananos/aislamiento & purificación , Microscopía de Fuerza Atómica , Electricidad EstáticaRESUMEN
A new ent-kaurane diterpenoid, Pseurata H (1), was isolated from the aerial parts of Rabdosia pseudo-irrorata C. Y. Wu, along with three known compounds, Pseurata B (2), Pseurata C (3) and Pseurata F (4). Their structures were established by extensive spectroscopic techniques (MS, IR, 1D and 2D NMR experiments).