Effect of temperature of milk acidification on rennet gel properties

Changes in mineral solubilization and rennet reaction rate were investigate d after decreasing milk pH to 6.3 by lactic acid addition at a temperature of acidification (TAC) of 25 or 35 degrees C with a short period of equilib ration. With increasing TAG, casein micelles retained higher amounts of Ca and P, and at a given temperature of coagulation, rennet clotting time was increased, and dG'/dt decreased. This effect was confirmed by the microstru cture of casein micelles during the first stage of the enzymic coagulation indicating that the aggregation of para-k-casein was observed later at high er TAG. The effect of TAC on rennet milk gel formation could be attributed to the nature of the micellar mineral content and the conformational state of casein micelles before rennet action.