Influence of konjac glucomannan on gelling properties and water state in egg white protein gel

The effect of konjac glucomannan (KGM) on nuclear magnetic resonance (NMR) relaxation behavior, water holding capacity (WHC), and gelling properties of egg white gel was studied. It was found that the values of gel strength and WHC reached the summit as the addition of KGM at 0.06wt.%. Multi-exponential function analysis of the T2 relaxation revealed that there were at least two categories of water with different states or mobility in egg white gel. Meanwhile, intrinsic T2 relaxation time of the immobile water in blending gel was longer than the bound water during gelation. The distribution of water in egg white gel was characterized by magnetic resonance imaging (MRI), which corresponded well with the conclusion of WHC. Further, scanning electron micrographs (SEM) suggested that WHC in the protein gel network was related to more porous gel microstructure. ► There were two categories of water with different states in egg white gel. ► Gel strength and WHC reached the summit as the addition of KGM at 0.06wt.%. ► SEM suggested that WHC was related to more porous gel microstructure.