Changes in gel properties and water properties of Nemipterus virgatus surimi gel induced by high-pressure processing

- Gel properties and water properties of Nemipterus virgatus surimi gel induced by high pressure of 400 MPa were improved significantly.
- Changes between the WHC and cooking loss of N. virgatus surimi gel induced by high pressure were opposite.
- The spin-spin relaxation time (T2) of N. virgatus surimi gel induced by high pressure was studied.
- Cross-linking of MHC via ε-(γ-glutamyl) lysine bonds was a major contributor in the formation of N. virgatus surimi gel induced by high pressure.

The effects of high-pressure processing (HPP) on gel properties and water properties of Nemipterus virgatus (N. virgatus) surimi gel, the correlation among spin-spin relaxation time (T2), water holding capacity (WHC) and gel properties were studied. The results show that breaking force, breaking displacement, rupture work and WHC of surimi gels increased and then decreased significantly as the pressure increased, and reached the maximum values at 400 MPa, larger than that from 0.1 MPa and heat-set samples. It was noteworthy that cooking loss, spin-spin relaxation time (T2), solubility and myosin heavy chain (MHC) bands intensity of N. virgatus surimi gel decreased and then increased significantly as the pressure increased, lower than that from 0.1 MPa and heat-set samples, and reached the minimum values at 400 MPa. In addition, a denser network structure of N. virgatus surimi gel was achieved at 400 MPa. It indicated that high pressure of 400 MPa not only contributed to WHC improvement of N. virgatus surimi gels, decreased cooking loss and solubility, but also forming a denser, micromesh-like, more uniform, and hierarchical 3D network structure via cross-linking of MHC. This structure resulted in the increase in WHC and improvement of gel properties.