Effect of microbial transglutaminase on NMR relaxometry and microstructure of pork myofibrillar protein gel

The effect of microbial transglutaminase (MTG) on nuclear magnetic resonance relaxation (NMR) behaviour, water holding capacity (WHC) and microstructure of pork myofibrillar protein (PMP) gel was studied. The enzymatic protein preparation had significantly lower values of spin-spin relaxation time (T (2)), higher WHC and more porous microstructure in comparison with the control system. T (2) was reduced from 226 ms (peak value) of the PMP gel containing no MTG to 188 ms of the PMP gel containing 2 U/g protein. However, no further decrease was shown when the concentration of MTG increased. The reduction was attributed to reduced mobility of water protons in the system. Scanning electron micrographs (SEM) showed the mobility of water in the proteins gel network was related to gel microstructure.