Changes in the viscoelasticity of maize starch pastes by adding sucrose at different stages

Effects of sucrose on the rheological properties of maize starch pastes were studied by steady and dynamic oscillatory viscoelasticity, DSC measurements, and microscopic observation. Sucrose concentrations varied between 0 and 55 wt%. When sucrose was added before heating of starch dispersions, the viscosity of the pastes increased with increasing sucrose concentration up to 20 wt% and decreased with increasing sucrose concentration above 20 wt%, although the viscosity of samples in the presence of sucrose was greater than that of the control at higher shear rate. A lower content of sucrose enhanced the swelling for starch granules, while a higher content of sucrose decreased the rate of swelling for starch granules and shifted the starch gelatinization temperature to higher temperatures. No decrease in the viscoelasticity of the pastes above 20 wt%sucrose concentration was observed by adding sucrose after heating of starch dispersions. The viscoelasticity of maize starch paste to which sucrose was added after heating increased with increasing sucrose concentration. (c) 2004 Elsevier Ltd. All rights reserved.