Probing water migration in Mozzarella cheese during maturation and heating utilizing magnetic resonance techniques

Abstract

Immediately following manufacture, Mozzarella undergoes significant structural rearrangement. During this maturation process, free water occupying the interstitial area around the fat channels is absorbed into the protein matrix. Magnetic resonance techniques allow the evaluation of molecular mobility within the porous cheese matrix. A 3 week maturation trial was conducted in which the relaxation and diffusion properties of water and fat were assessed at room and elevated temperatures. Relaxation measurements at 20 °C highlighted the progressive change in the mobility of water as it became more associated with the casein gel matrix over the trial period. Heating was found to cause an increase in molecular mobility as the association between the casein and water lessened at elevated temperatures. This work illustrated that the diffusion and relaxation properties of water within Mozzarella on heating changed over a three week maturation period. The data also indicates that the diffusion of water at low temperatures was dominated by free water, while the diffusion at elevated temperatures was likely dictated by the degree of connectivity within the protein matrix.