Measurement of Alkaline Earth Ion Concentrations by Rennet Action

THE relatively high temperature coefficient of the second or cationic precipitation stage of rennet action on casein allows its separation from the first or enzymic stage to be made by appropriate choice of temperatures1. Thus the first stage can be completed at 0-5° C., and the second afterwards initiated at about 35° C. The coagulation time at the higher temperature, extremely sensitive to variations in alkaline earth ion concentration within a fairly narrow range, can then serve as a measure of such concentrations.