Rheological properties of casein micelle gels: the influence of calcium concentration on gelation induced by rennet.

Rheological studies on the gelation of casein micelles using rennet have been performed in relation to cheese making. The influence of calcium concentration on the time course of storage and loss modulus was investigated using rheological measurements. Observed gelation curves at 30 degrees C were well approximated by first-order reaction kinetics except for the very short time after gelation occurred. The saturated modulus decreased with decreasing calcium ion concentration in the range from 4.5 to 9 mM. The rate constant of gelation, Kg decreased linearly with decreasing calcium ion concentration. A minimum amount of calcium was needed for gelation to occur. Kg was inversely proportional to the latent time, tL. The value of the product of Kg and tL for the casein micelle gels containing various calcium concentrations was 0.4.