A COMPARATIVE STUDY ON RHEOLOGICAL BEHAVIOUR OF AQUEOUS SUSPENSIONS OF CYSTOSEIRA BARBATA AND ULVA LACTUCA MACROALGAE

Rheological behaviour of aqueous suspensions of C. barbata and U. lactuca was studied at different values of temperature (25, 50 degrees C), cellulase/dried macroalgae ratio (0, 16 U/mgdma), and suspension mass concentration (5-15%). At 25 degrees C, the suspensions without cellulase obeyed the Ostwald-de Waele power law and their apparent viscosities (0.25-15.31 Pa.s for C. barbata and 0.04-5.35 Pa.s for U. lactuca) increased with macroalga concentration, whereas those containing cellulase behaved as Bingham plastics and their viscosities (0.113-0.141 Pa.s) were invariant with macroalga species and concentration. At 50 degrees C, all suspensions were power law fluids with similar apparent viscosities (0.35-50.09 Pa.s).