Assessment of the changes in the structure and component mobility of Mozzarella and Cheddar cheese during heating

During heating the structure of cheese changes which impacts on the functional properties. This research compares the rheological and structural changes during heating of three types of cheese: Mozzarella, medium Cheddar, and aged Cheddar. We use small amplitude oscillation rheology and a variety of magnetic resonance techniques to study these changes. The complex viscosity of Mozzarella and the two Cheddar samples varied with temperature. A number of structural changes were identified as being responsible for variations in the rate of change in viscosity. Magnetic resonance indicated that as cheese is heated there is a progressive increase in the quantity of free water present in the cheese structure. The diffusion properties of water within the structure allowed information relating to the tortuosity and the surface to volume ratio of pores to be calculated, and subsequent analysis indicated that these properties are temperature dependent. These results indicate that significant information regarding the structural dynamics of various constituents of cheese can be monitored during heating using rheology and magnetic resonance. In particular the MR data include the first application of time dependent diffusion measurements to characterize the molecular dynamics associated with structural changes in cheese.