Structural and rheological properties of polysaccharides from mango (Mangifera indica L.) pulp

The structure and rheological properties of water-soluble polysaccharides from industrialized mango pulp were investigated. Soluble fraction (SF) 2 was heterogeneous on high performance size exclusion chromatography, giving two peaks as determined by multi-angle laser light scattering and refractive index detectors. The presence of starch in SF2 was demonstrated by a positive iodine reaction and by (13)C nuclear magnetic resonance (NMR) spectroscopy. The presence of pectic polysaccharides was shown by a calorimetric method, (13)C-NMR spectroscopy and carboxyl reduction. The main pectic polysaccharide was polygalacturonic acid; type I rhamnogalacturonan was also detected. Analysis of the rheological properties of SF2 showed a pseudoplastic behavior up to 3 gl(-1). 'Creep and recovery' tests and analysis performed under a dynamic state revealed a weak gel character for solutions at concentrations of 15, 20 and 30 g l(-1). (C) 2002 Elsevier Science B.V. All rights reserved.