Effect of Pre-shearing and Temperature on the Yield Stress of Stirred Yogurt

The yield stress of stirred yogurt was measured by the vane viscometer at different pre-shearing conditions, such as pre-shear speed, pre-shear time, and wait time, and temperature (12-38°C). The yield stress ranged from ~17.6 to 10 Pa and from 34.2 to 11.9 Pa, depending on the pre-shearing conditions and temperature, respectively. The preshear speed and the wait time significantly affected the yield stress. The temperature dependence of the yield stress was described by the Eyring’s kinetic model. The linear function of the temperature on the yield stress was limited at the 22°C, and at the above 22°C, the yield stress was maintained to be a constant (~12.5 Pa).