Pseudoplastic and viscoelastic behaviour of molasses

Low-grade C molasses exhibit unusually large jet swell. Some authors have attributed this behaviour to viscoelasticity. We will present rheometrical data which show that lowgrade molasses are indeed viscoelastic. Viscoelasticity exacerbates processing problems. Viscoelasticity is attributed to dissolved high Mw polymers such as dextran. Polymer molecules resist stretching and as a result in complex flow geometries the fluid avoids moving through small diameter channels or capillaries such as those found in a packed bed of sugar crystals. The viscosity behaviour of a C molasses was characterised over 5 decades of shear rate. It displayed Newtonian behaviour at low shear rates (-1O-4s-1). For the C molasses at 49.4°C the flow behaviour index decreased to a minimum of about 0.2 at 0.02s-1 and then increased back to 0.7 at the highest shear rate measured, 3s-1.