Influence of milk-clotting enzymes on acidification rate of natural whey starter culture

Abstract

The aim of this work was to study the influence of milk-clotting enzymes on whey starter culture and hard cheese-making. Four cheeses were simultaneously prepared per cheese-making day, and the experiment repeated on eight consecutive days. Adult bovine rennet was used in control cheeses, and three formulations of fermentation-produced chymosin in experimental cheeses. Whey cultures were obtained from the whey of the precedent cheeses, incubated individually 24 h at 42ºC. pH of the control and the experimental whey did not differ before incubation, but it was significantly higher for pure chymosin’s whey after 24 h. Soluble nitrogen content in tricloroacetic acid 2 and 12 %, and in phosphotungstic acid 2.5 % was significantly lower for all experimental whey samples than in control whey. That is likely the reason of the delay in acidification rate of whey cultures, when bovine coagulant is replaced by fermentation produced chymosin in hard cheese-making.