Rheological characteristics of intermediate moisture blends of pregelatinized and raw wheat starch.

Abstract

Rheological properties of intermediate moisture (35-45% wet basis) doughs from pregelatinized and raw wheat starch blends of various ratios were characterized using off-line capillary rheometry and online slit-die extrusion. In the case of capillary rheometer, viscosity of blends decreased by up to 50% as pregel starch concentration increased from 5 to 45%, whereas tests could not be conducted beyond 45% pregel starch concentration. For slit-die extrusion, viscosity was at a minimum at 60% pregel concentration, and it decreased by as much as 65% as pregel concentration increased from 0 to 60%. As pregel concentration increased (from 5 to 45% for the rheometer and from 0 to 60% for the extruder), the amount of water available in the system for gelatinization of existing raw starch granules decreased due to the stronger water-binding capacity of pregelatinized starch. This led to decreased additional conversion in the rheometer and extruder, which in turn caused a decrease in the volume fraction of starch and a reduction in viscosity.

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Cite this paper

@article{Alavi2002RheologicalCO, title={Rheological characteristics of intermediate moisture blends of pregelatinized and raw wheat starch.}, author={Sajid H Alavi and Kwan-Han Chen and S. Saqib H. Rizvi}, journal={Journal of agricultural and food chemistry}, year={2002}, volume={50 23}, pages={6740-5} }