Effect of various blends of camel chymosin and microbial rennet (Rhizomucor miehei) on microstructure and rheological properties of Iranian UF White cheese

• Clotting enzymes are crucial role in cheese making and cheese rheology.
• Clotting enzymes may also changes cheese microstructure.
• Camel chymosin has different clotting power than others.
• Microbial rennets are stronger proteolytic activity than camel chymosin.
• Differences in clotting power changed cheese rheology.

Various blends of milk coagulants Rhizomucor miehei protease and camel chymosin were mixed at levels of 100:0, 75:25, 50:50, 25:75 and 0:100, respectively and used in the manufacture of Iranian ultrafiltered (UF) White cheese. Effect of different blends of these coagulants on microstructure and rheological properties of Iranian UF White cheese were studied during 90 days of ripening. The results showed that both microstructure and rheology of the cheeses were influenced by type and concentration of these coagulant blends due to their different proteolytic activities. Use of high concentrations of camel chymosin resulted in a more compact protein network and firmer structure in the cheeses. Increasing levels of camel chymosin in the coagulant blends increased the storage (G′) and loss (G″) moduli and decreased loss tangent (δ) in the cheeses. In conclusion, increasing levels of camel chymosin provided less protein breakdown and more solid-like viscoelastic structure in UF cheeses.