Yield Stress of Foods Using a Vane

F ure 3-14 Torque versus Time Plot with a Vane in Controlled Strain Operation Where the Maximum Torque is Used to Calculate the Yield Stress. 

The vane yield stress technique is a useful technique that applies small deformations in the initial stages and large deformations in the latter stages. From the initial linear portion of the torque-time curve at a low shear rate, for example, 0.01 s , the shear modulus (G) can be calculated as  

Michaels and Bolger (1962) and Metz and others (1979) discussed a structural model for dispersions of particle floes that associate randomly to form weakly bonded aggregates and tenuous networks, giving rise to plastic properties. Genovese and Rao (2003a) showed that by applying an energy balance at the point of maximum 

The concepts of inter-particle bonding, net work structure, and viscous dissipation, as well as texture maps should be applicable to all structured dispersions, such as cosmetics and other consumer products. The vane yield stress test is a versatile test in which a fluid food is subjected to small deformations during the initial stages and large deformations during the latter stages of the experiment. From the former set of linear data, a shear modulus (G) of the sample can be estimated. 

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