Flow behavior of coarse solid-liquid food mixtures

Abstract

The effects of increasing carrier viscosity, particle size, and particle concentration and variations in particle shape on the flow behavior of coarse solid-liquid food mixtures were investigated using a simulated coarse solid-liquid food mixture as the test material and parallel plate viscometry. Flow curves resulting from testing that was limited to a maximum test shear rate of 8·36 s −1 were represented by power law equations. Regardless of the carrier medium used, m increased both with particle size and particle concentration. The rate of increase in m with concentration was greater in mixtures formed with a more viscous carrier medium. The increase of m with concentration was also observed for different particle shapes with the rate of increase successively greater for discs, rods, then cubes. The result for shapes can be related to the surface area of each particle facing the flow direction. Values of n were mostly found to decrease with particle concentration. This increase in m values and decrease in n values with increasing particle concentration is consistent with what has been generally reported in the literature for foodstuffs. The deviating result of increasing n values with concentration obtained for mixtures with 0·64 cubes apparently resulted from an inability to test flow behavior at higher test shear rates because of instrument limitations.