30E-10 |
Interrupted helical screw to evaluate fluid foods with large particulates |
A. P. OMURA, Dept. of Agricultural Engineering, Michigan State University, East Lansing, MI 48824 and J. F. Steffe. Although much is known about the rheological behavior of homogenous fluid foods and fluid suspensions, the area of coarse solid-liquid food materials is relatively uncharted. This is an important area of work because many prepared foods are composed of these complex materials. Mixer viscometry is most appropriate for fluids containing large particles. An impeller used to determine rheological properties of fresh concrete has been redesigned to analyze fluid foods with large particulates. The objective of this study was to characterize and test the performance of an interrupted helical screw for its ability to accurately represent the rheological behavior of fluid foods with large particulates. Determination of the mixer viscometer constant was accomplished using the torque curve method. Food material samples used in this study were salsa, pork and beans, beef stew, clam chowder, and cream corn. The impeller was attached to a viscometer with data logging capabilities. Angular speed ranges were based on the torque capacity of the instrument. The mixer viscometer constant was found to be within the range of constants of other impellers. Raw data were fitted to rheological models. Fluid foods with large particulates were found to behave as non-Newtonian fluids. Power curves were constructed to characterize the impeller. The interrupted helical screw has the potential to be a reliable rheological tool to evaluate the flow behavior of fluid foods with large particulates.
Session 30E, Food Engineering: Rheology and texture
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