ULTRASONIC-ATTENUATION MEASUREMENTS FOR ESTIMATING MILK COAGULATION TIME

An ultrasonic system has been developed to employ a pulse-transmission method of measurement during coagulation of rennetted milk. The ultra sonic waves were transmitted through the milk and the coagulation proc ess was followed after adding the enzyme. The observed changes in ultr asonic attenuation during coagulation were used to predict the coagula tion time indicating the onset of coagulation. Coagulation times were also determined by measuring the apparent viscosity of the coagulum as suggested in the literature. Statistical analysis indicated that ther e was no significant difference (at 95% level) between the coagulation times determined by both methods. Thus, the ultrasonic method has pot ential for nondestructively estimating the coagulation time of rennett ed milk. Determination of coagulation time is useful in evaluating the effectiveness of different enzymes under varying conditions.