Understanding calcium equilibrium in cheese during ripening and its effects on functional properties of cheese

The overall objectives of this thesis were to investigate changes during ripening in Ca equilibrium and the functional properties of cheeses made with different manufacturing variables (such as lactose content, manufacturing pH and washing).;The changes in insoluble Ca content of Cheddar cheese during ripening were significantly (P<0.05) affected by cheese manufacturing variables, such as, draining pH. Increasing the lactose content in milk did not affect the insoluble Ca content of cheese during ripening. Cheeses with pH <5.0 showed very limited meltability. The reduced meltability with low cheese pH was presumably due to the dominant effects of increased electrostatic attraction between casein particles at low pH values (<5.0).;There was a decrease in insoluble Ca content of washed-curd cheeses during the first mo of ripening. There were no major changes in cheese pH during ripening when curd-washing was used even with low manufacturing pH values. The meltability of cheese made from high lactose milk was improved by using curd-washing which prevented a large drop in cheese pH. Curd-washing significantly (P<0.05) affected the insoluble Ca content of cheese during ripening as well as the theological and melting properties of cheese.;Different methods of curd washing (soaking curds vs. spraying water on the surface) resulted in cheeses with similar total Ca content but different insoluble Ca contents during ripening. A decrease the insoluble Ca content of cheese during ripening was observed even with an increase in cheese pH. Different washing methods significantly (P<0.05) affected the amount of insoluble Ca content of cheese during the early period of ripening as well as theological properties.;This research provides a better understanding of the Ca equilibrium in cheeses made from various manufacturing methods and the information derived from this research will help cheese makers to predict changes in Ca equilibrium during ripening and the impact of these changes on cheese attributes.