Plant food dispersions

Because of the compressible nature of food dispersions, the direct determination of the magnitude of centrifugal force employed in the separation of the phases. Therefore, rheological properties of plant food dispersions, such tomato concentrates and concentrated orange juice, are based on the mass of pulp. In starch dispersions, they are based on the mass fraction of starch granules, denoted as cQ, as described in Chapter 4. 

Plant food dispersions such as tomato concentrates and concentrated orange juice are important items of commerce. The viscosity function and the yield stress are two important rheological properties that have received considerable attention. Corrections for slip, due to the formation of a thin layer of fluid next to solid surfaces, in a concentric cylinder viscometer depended on the magnitudes of applied torque and on the shear-thinning characteristics of the dispersion. Mixer viscometers were used for obtaining shear rate-shear stress and yield stress data, but the latter were higher in magnitude than those obtained by extrapolation of flow data. 

It is well known that insoluble solids content of plant food dispersions plays an important role in the rheological behavior of the dispersions (21, 43., 44). For apple sauce samples modified by the addition of pulp, good... 

That the magnitude of p. decreased with increase in pulp content is note worthy because it means that plant food dispersions with high solids content will be highly viscous, but will exhibit little wall slip. In contrast, dispersions with relatively low solids content will exhibit significant wall slip. It must be emphasized that Equation 11 is an empirical equation derived for the food samples employed in this study. While it provides important trends about wall slip, the equation cannot be extrapolated beyond the range of variables employed in this study. 

Engineering Data on Flow of Plant Food Dispersions. 

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