RHEOLOGICAL BEHAVIOUR OF THREE BIOPOLYMER/WATER SYSTEMS, WITH EMPHASIS ON YIELD STRESS AND VISCOELASTIC PROPERTIES

Flow and viscoelastic properties of three thickened systems are presented: aqueous solutions of locust bean gum, of xanthan and a dispersion of a crosslinked waxy corn starch. Creep measurements allow investigations at very low shear rates. The existence of a yield stress is discussed. Flow was observed at low shear rates, but the starch paste exhibited pseudo-yield stress behaviour. Dynamic measurements were performed and the relationships between flow curves and mechanical spectra are discussed.