Cereal Chem 68:347-351   |  VIEW ARTICLE

Oscillatory Rheometry of Starch-Water Systems: Effect of Starch Concentration and Temperature.

L. M. Hansen, R. C. Hoseney, and J. M. Faubion. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

An oscillatory probe rheometer was used to measure the rheological properties (G*, G', and G") of corn starch-water systems throughout the sol-to-gel transformation. Starch-water suspensions of 5, 7, and 10% (w/w) were heated to endpoint temperatures (EPTs) of 81, 86, and 92 C, and the rheological properties of the pastes and resulting gels were measured. As starch concentration increased, G' increased. For all concentrations analyzed, G' varied depending on EPT. In general, G' was lower for suspensions heated to 81 C than for suspensions heated to 86 or 92 C. The temperature of the sol-to-gel transformation was determined from the slope of the loss tangent and was dependent on starch concentration and EPT. The higher the starch concentration, the higher the temperature of the sol-to-gel transformation. Regression analysis determined that the amount of amylose and amylopectin leached from the granules, the swelling power of the granules, and the insoluble granules all interact and affect the rheological properties of the resulting gel. High soluble amylose levels and swelling powers increased gel elasticity, whereas high levels of soluble amylopectin were detrimental to gel formation and reduced elasticity.