The effects of entanglement concentration on the hydrodynamic properties of cereal starches.

BACKGROUND: The hydrodynamic properties of four cereal starches in dilute and semi-dilute aqueous solutions were investigated using an Ubbelohde viscometer, a transmission electron microscope and steady shear rheological measurements.

RESULTS: The results indicated that the starch solutions showed the nonlinear shape of the ηsp /c versus c curves in dilute solutions, followed by a linear increase to different extents thereafter. The intrinsic viscosity might be positively correlated with the entanglement concentration (ce ). Compared to normal maize and wheat starch solutions, ce influences more significantly the network formation of normal and waxy rice starch solutions. At concentrations ≤ ce , the gelatinized cereal starch solutions hardly exhibit shear thinning behavior, whereas shear thinning behavior developed at concentrations > ce , at which the solutions were pseudoplastic and thixotropic.

CONCLUSION: The obtained information will be very useful, based on ce as a reference value, in regulating the starch concentration suitable for different industrial applications. © 2016 Society of Chemical Industry.