STRUCTURE, MELTABILITY, AND FIRMNESS OF PROCESS CHEESE CONTAINING WHITE CHEESE

White cheese made by coagulating heated milk (90-degrees-C) with a 2.5% citric acid solution to pH 5.5 consists of casein particles having a characteristic core-and-shell ultrastructure. The presence of this White cheese in process cheese can be detected by transmission electron microscopy on the basis of the core-and-shell ultrastructure which is stable during cheese processing. White cheese additions may be detected at levels equal to or higher than 8%. White cheese, which does not melt alone when heated, increases meltability of the process cheese in which it is present as an ingredient. Meltability increases at all White cheese concentrations examined (8, 16, and 33%) with trisodium phosphate used as the melting salt. With sodium citrate, there is a 14% increase in meltability at 8% White cheese. Meltability of process cheese containing 16% White cheese is about the same as the control process cheese, and meltability of process cheese containing 33% White cheese is decreased by 20%. Firmness of process cheese made with sodium citrate increases as the proportion of White cheese is increased from 8 to 33% but decreases in process cheese made with trisodium phosphate except at the highest White cheese concentration.