Mozzarella cheese: impact of coagulant concentration on chemical composition, proteolysis, and functional properties

Three vats of low moisture, part skim Mozzarella cheese were produced with three different concentrations of coagulant (double-strength chymosin derived by fermentation; 0.1, 0.08, and 0.06 ml/kg of milk, representing 100, 80, and 60% of normal usage). Cheese was made by the milled-curd, no-brine method, replicated on 3 different d as a 3 X 3 Latin square design. There were no differences in moisture, protein, salt, calcium, and initial pH of cheese from coagulant concentration. Soluble N (12% TCA and at pH 4.6 in acetate buffer), alpha s- and beta-CN, meltability, texture profile analysis, apparent viscosity, and free oil of cheese were monitored up to 50 d of storage at 4 degrees C. With increased storage time, soluble N contents, meltability, and free oil increased; alpha s-CN, hardness, springiness, and apparent viscosity decreased. Differences in coagulant concentrations had a significant impact on free oil, and interactions were significant between effects of coagulant concentration and storage time on soluble N contents. Lower coagulant resulted in slightly lower soluble N and free oil. Overall, decreasing the concentration of coagulant by up to 40% had limited impact on the composition, proteolysis, and functional characteristics during 50 d of refrigerated storage.