Effect of Cyperus esculentus polysaccharide on Cyperus esculentus starch: Pasting, rheology and in vitro digestibility

This study investigated the effects of varying amounts of added Cyperus esculentus polysaccharide (CEP) on the physicochemical and structural properties, as well as in vitro digestibility, of homologous Cyperus esculentus starch (CES). Compared to CES, the CES-CEP complexes showed reduced peak viscosity and breakdown value, and improved thermal paste stability of starch. Rheological properties showed that adding CEP reduced the consistency coefficient and pseudoelasticity of the complexes, thus increasing their resistance to shear thinning. FTIR analysis suggested the absence of covalent binding between CES and CEP. SEM showed a more homogeneous and dense gel structure, particularly in the CES-1.0%CEP sample. During in vitro digestion, the content of resistant starch in the complexes increased after CEP was added. Analysis of the interaction forces showed that the CES-CEP complexes had stronger hydrogen bonding and electrostatic interaction. This study offers valuable insights into the potential applications of CEP in starch-based foods. •Cyperus esculentus polysaccharide (CEP) were co-gelatinized with starch.•Structure and physicochemical properties changed after CEP were added.•CEP improved thermal stability of starch pastes while reduced pseudoplasticity.•CEP affected the functional properties of digestion.