Abstract:

In order to investigate the effect of pH on water-holding capacity and water mobility of heat-induced gelation from rabbit myosin, gelation properties of rabbit myosin were characterized through determining relaxation time (T2) of water using low-field nuclear magnetic resonance (NMR), and water-holding capacity (WHC), hardness and ultra microstructure of the gel. NMR results indicated that relaxation time for immobile water (T22) and relaxation time for free water (T23) exhibited a decrease as the increase of pH, which suggested that the slow water mobility resulted from the increased number of negative charge in myosin. Principal component analysis results revealed that T22 and T23 relaxation time had strong correlation with WHC, hardness and diameter of the gel. A significant difference was observed between samples near pI points and other samples. Moreover, the number and distribution of surface charge exhibited an effect on curling and stretching of myosin molecules, and finally affected WHC, hardness and mesh diameter of the gel, while T2 relaxation time could reflect this tendency well.

Key words: myosin, gel, low-field NMR, pH value, water-holding capacity