Effect of Acidulants and Milk-Clotting Enzymes on Yield, Sensory Quality, and Proteolysis of Pizza Cheese Made by Direct Acidification

Various acidulants (hydrochloric, phosphoric, and lactic acids) and milk-clotting enzymes (pepsin, veal rennet, and a con> mercial fungal rennet) were used to make Pizza cheese by the direct acidificationcontinuous agitation procedure without added lactic starter cultures. Recovery of solids-not-fat was the highest in the finished cheese when phosphoric acid was used. The type of acid had no effect on recovery of fat. Fat and solids-not-fat recovery in cheese was not affected by the type of enzyme. Proteolysis, as measured by levels of nitrogen soluble at pH 4.4 and fornml nitrogen, in cheese during storage at 4 C was greatest in lots made with fungal rennet and least in those made with pepsin. Levels of nitrogen soluble in 12% trichloracetic acid were lowest in cheese made with veal rennet. Flavor grades after one week and one and two months of storage at 4 C were highest in cheese made with pepsin and lowest in cheese made with veal rennet. Cheese nmde with veal rennet was criticized for excessive bitterness after one month.