Resumen de Components of Vane Yield Stress of Structured Food Dispersions

D. B. Genovese, M. Anandha Rao

• The vane technique was used to determine the static (σos) and dynamic (σ0d) yield stresses of 6 commercial foods: mayonnaise, mustard, ketchup, applesauce, and 2 brands of tomato puree (samples TD and TR). The samples, other than TR, exhibited shear-thinning behavior. For those samples, based on a model proposed earlier, the contributions of bonding (σ-b), network (σ-n), and viscous (σv to yield stress of the products were determined. For the homogenized products, σb > σn, whereas for those processed in a finisher, σn > σb. Because sample TR exhibited shear-thickening behavior, the model to estimate yield stress components was not applicable. The structural conditions necessary for the validity of the proposed model are established. Equilibrium stress (σ∞) values obtained by extrapolation of vane torque data to infinite time were comparable to σ0d values.