The functional properties of polymerised whey proteins may be similar to those of emulsifying salts; they are able to thicken the cheese mass, bonding the ingredients due to the ability to emulsify fat and high water absorption. The objective of this study was to examine the effect of polymerised whey protein isolate as emulsifying salts replacer on textural, rheological and meltability properties of acid casein model processed cheeses. Partial replacement of emulsifying salts with polymerised whey protein isolate (0.2–0.4% WPI) increased textural features and viscosity; however, higher WPI concentrations decreased hardness and adhesiveness. The highest initial values of storage and loss moduli were noted at 0.4% WPI concentration, which was correlated with the highest hardness and adhesiveness. All samples tested were characterised by good meltability (Schreiber test number > 4). Moreover, replacement of emulsifying salts with polymerised WPI improved the spreadability of processed cheeses.