Investigation of the effects of mechanical post-processing with a colloid mill on the texture properties of stirred yogurt

Texture properties of stirred low-fat yogurt were investigated in terms of processing after fermentation. The yogurt gel was pumped through a colloid mill at two gap widths and various peripheral velocities of the rotor. The storage modulus and yield stress were measured after 1 day and after 3 weeks, and the occurrence of syneresis was noted. The main factor for the structural degradation in the shear gap was the mean peripheral velocity of the rotor, rather than the apparent shear rate. Syneresis is related to a certain level of the storage modulus. The yield stress correlated with the storage modulus.