Investigation of imitation cheese matrix development using light microscopy and NMR relaxometry

The hydration of rennet casein and emulsification of fat were monitored throughout imitation cheese manufacture by monitoring changes in water mobility using NMR relaxometry and cheese microstructure by light microscopy. The changes in water mobility and microstructure observed are consistent with a four-stage model of protein hydration/matrix development in imitation cheese manufacture. These stages included the wetting and swelling of casein particles, the formation of a congealed matrix, the development of a more cohesive matrix and the formation of a homogeneous cheese mass. The initial two stages were dominated by protein–water and protein–protein interactions, while the latter stages were predominately governed by protein–fat and protein–water interactions. This study followed imitation cheese manufacture in situ by monitoring changes in viscosity, allowing a realistic insight into the development of an imitation cheese matrix.