Yield Stress and Relative Viscosity of Tomato Concentrates: Effect of Total Solids and Finisher Screen Size

Yield stresses of tomato concentrates, prepared using two finisher screens (0.69 mm and 0.84 mm diam) were determined using the vane method, Casson model, and dynamic rheological data. Magnitudes of vane yield stress were higher than those using other methods. They increased with increase in total solids and were about the same in concentrates from both screen sizes. Magnitudes of Casson viscosities of concentrates and serum viscosities from 0.84 mm screen were slightly higher than those from 0.69 mm finisher screen.