Flow Behavior of Concentrated Starch Dispersions Using a Tube Rheometer of Novel Design

A tube rheometer of novel design was used to study the flow properties of starch dispersions with concentration from 7 to 30% w/w at 95C. The flow properties of maize starch dispersions were largely influenced by the time of cooking and shearing that elapsed before the measurements were taken. Viscosity gradually decreased with the time of shearing until it reached a minimum value which then remained constant. Viscosity measurements, taken at 95C and 75C, of dispersions of 10 and 15% w/w starch concentration indicated that the activation energy of the flow was concentration dependent. The flow behavior shown by the starch dispersions was attributed to the presence of the amylose matrix rather than to swollen granules.