36D-26 |
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R. L. MCINTIER, Dept. of Food Science, Univ. of Wisconsin - Madison, 1605 Linden Drive, Babcock Hall, Madison, WI 53706 and R. K. Connelly, Dept. of Food Science, Univ. of Wisconsin, Madison, 1605 Linden Dr., A-13 Babcock Hall, Madison, WI 53706-1565. Dough mixing is the most significant stage in the production of bread products. Currently, no single test or analytical procedure can provide a complete measure of flour potential or strength for a particular bread-making process. The Farinograph and Mixograph, two common devices for assessing flour strength and moisture absorption during mixing, measure the torque and work input required to produce optimally mixed dough using very different geometries and mixing actions. Neither mixer measures in fundamental rheological units preventing meaningful comparisons between the two. They often provide inconsistent information, especially when testing very hard flours. Our objective is to develop a relationship uniting information obtained from both mixers by charting the course of dough development during mixing in the two mixers at varying speeds. Doughs made from both soft and ultra hard wheat flour were mixed at varying speeds using the 50g Farinograph, a twin sigma blade mixer, and the 10g Reomixer, a planetary pin mixer similar to the Mixograph. Hydration effects were removed from the mixing process through use of a slow premix followed by a resting interval. Work and strain input to reach peak torque was used to compare the two mixers. Results confirm the dependence of dough development on mixing speed at low speeds. Dough development at high speeds is attributable solely to energy input. The speed where dough development becomes rate independent is different in the two mixers and serves as a comparison point for the two mixers. Once the relationship of mixing conditions to dough development is better understood, the difference in test results between the two instruments can be explained more easily. This will lead to more reliable information for use in the selection of appropriate wheat cultivars for breeding, as well as in choosing appropriate flours, formulations and processing parameters for a given product.
Session 36D, Food Engineering: Rheology
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |