Sequential extraction and physicochemical characterization of polysaccharides from chicory (Cichorium intybus) root pulp

Polysaccharides from chicory root pulp (CRP) were extracted and structurally characterized. Different extractants were sequentially used to obtain three extracts, referred to as the water-extracted polysaccharides (WEP), chelate-extracted polysaccharides (CEP) and acid-extracted polysaccharides (AEP). The results indicated that WEP, CEP and AEP accounted for 5%, 9.3% and 3.2% of the starting chicory root pulp. All of the extracts differed from each other with respect to their chemical compositions, and their macromolecular and functional properties. WEP was found to be a mixture of both inulin and pectin; however, CEP and AEP belonged to the group of typical pectic substances due to their high content of galacturonic acid (GalA) and neutral sugars. Comparison of the molecular weight distribution patterns revealed that CEP is more homogeneous than WEP and AEP. CEP gelled with Ca2+ due to the high GalA content (71.1%), the low degree of methylation (30.8%) and the high molecular weight (87,545 g/mol). Unlike CEP, AEP contained more hydrophobic structures, such as proteinaceous material (5.5%) and acetyl groups (DA 17.1%), resulting in the ability to stabilize the oil/water emulsion. Results obtained in the present work indicate that the extraction yield, chemical features and functional properties of chicory root pulp polysaccharides depend greatly on the type of extractant.