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Solution properties of a heteropolysaccharide extracted from pumpkin (Cucurbita pepo, lady godiva)

Song, Yi, Zhao, Jing, Ni, Yuanying, Li, Quanhong
Carbohydrate polymers 2015 v.132 pp. 221-227
Cucurbita pepo, autoclaving, gas chromatography-mass spectrometry, gel chromatography, glucose, hydrodynamics, light scattering, models, molecular weight, polysaccharides, pumpkins, viscometry, viscosity
A water-soluble galactoglucofucomannan was extracted from pumpkin (Cucurbita pepo, lady godiva variety). GC–MS analysis indicated that the polysaccharide was composed of 1,6-linked-glucosyl, 1,2,6-linked-mannosyl, 1,3,6-linked-mannosyl, 1,2,6-linked-galactosyl, 1,2,6-linked-galactosyl, terminal fucosyl and terminal glucose. The solution properties of the polysaccharide were studied systematically by using size-exclusion chromatography combined with multi-angle laser light scattering, viscometry and dynamic light scattering at 25°C. The weight average molecular masses (Mw), intrinsic viscosity [η], radius of gyration (Rg) and hydrodynamic radius (Rh) were found to be 12.7×105g/mol, 780ml/g, 68nm and 116nm, respectively. The fraction dimension and value of ρ (Rg/Rh) of the polysaccharide revealed that it existed in a sphere-like conformation in distilled water. The dependence of zero shear specific viscosity on the coil overlap parameter was analyzed using different models. Furthermore, degradation of samples upon autoclaving has been observed and quantified by intrinsic viscosity determination and SEC-MALLS.