Effect of sodium chloride and pH on the rennet coagulation and gel firmness

The effect of sodium chloride concentration and pH of milk at renneting on the rennet clotting time (RCT) and gel firmness was studied. The results showed that rennet clotting activity and gel firmness decreased with increasing NaCl concentration in milk. The RCT increased as the pH of the salted milk decreased below 6.4. Milk containing 5 and 10 g NaCl/100 g did not coagulate at pH 5.0. The gel firmness increased with decreasing milk pH to 6.2 for unsalted milk. However, the firmness decreased as the pH of milk decreased below 6.2. In case of using salted milk, the firmness decreased as the pH at renneting dropped below 6.4.