Effects of Lowering Ca Concentration on Rennet Gel Formation of Casein Micelle Solution

Abstract

The effects of lowering Ca concentration on the formation of rennet gel of casein micelle solution were investigated using a gel firmness tester. The changes in gel firmness after renneting was continuously measured under non-destructive conditions. The rennet gelation time, the initial gelation velocity and the maximum gel firmness were obtained from the renneting-gel firmness curves. It was found that the rennet gelation time increased with a decrease in the Ca concentration of casein micelle solution, while the initial gelation velocity and the maximum gelation firmness increased. When lysozyme was added into the casein micelle solution having a lower Ca concentration, the values of the three gel parameters became similar to those of the control samples. For these reasons, lysozyme can perform the same rolle as Ca during gelation of the renneted casein micelle solution.