Insight into the mechanism of optimal low-level pressure coupled with heat treatment to improve the gel properties of Nemipterus virgatus surimi combined with water migration.

The effect of optimal low-level pressure coupled with heat treatment (OPH treatment) on the gel properties and water migration of Nemipterus virgatus surimi was studied and compared with optimal high-pressure processing treatment (OP treatment) and traditional two-stage heat treatment (H treatment). Furthermore, the mechanism of OPH treatment in improving the gel properties were explored based on myosin. OPH treatment was found to be more conducive in improving the gel strength and water-holding capacity (WHC) of surimi gel than H or OP treatments. Moreover, OPH treatment induced an increase in the proportion of myosin β-sheets and exposed more intramolecular Tyr residues as compared to the other two treatments, which promoted myosin to form large protein clusters through disulfide bonds and hydrophobic interactions, and a honeycomb three-dimensional network structure with larger fractal dimension, lower porosity, smaller water hole diameter, and a greater number of water holes, was obtained. These helped the OPH-induced surimi gel lock in more unfrozen bound water and immobile water, and ultimately rendered better gel properties.