Dynamic rheology of corn starch-sugar composites

The effect of sugars (sucrose, glucose, and xylose) at different concentrations (0%, 10%, 20%, and 30%) on dynamic rheological properties of corn starch pastes (5% w/w) was investigated by small-deformation oscillatory measurements of storage moduli (C) during cooling and aging. Magnitudes of G' increased sharply during cooling (front 95 to 4 degreesC) and decreased with increase in concentration of sugar. The xylose was found to show the greatest reduction in the values of G' among the sugars tested. G' values as a function of aging time (10 h) at 4 degreesC increased rapidly at initial stage and then reach a pseudoplateau region at long aging times. Increasing the sugar concentration resulted in the decrease in pseudoplateau values. In general, G' values in corn starch-sugar composites were reduced in the presence of sugars, and decreased in the following order: xylose > sucrose > glucose > control (no sugar). (C) 2003 Elsevier Ltd. All rights reserved.