P. Boyanova, P. Panayotov, B. Milenkov, H. Dinkov

Abstract. In the following work possibilities to monitor the acid coagulation dynamics by rotational viscometer are discussed. There is established suitable speed of rotation of the cylinder, in line with the delicate structure of the gel. The time to achieve the isoionic point in the acid coagulation of milk can be determined by changing the viscosity. The obtained results give grounds to assert that the viscometers cannot be used alone for the detailed monitoring of acid coagulation. Viscometers can be used as the reference method for monitoring changes of dynamic viscosity of milk during acid coagulation and determining the point of gelation. To establish the parameters of acid coagulation dynamics titratable acidity (°T), pH and lactic acid accumulation on milk (%) were followed.