Abstract:

The texture, cross-linkage and microstructure of MTGase-induced silver carp surimi gels at various setting
times were measured to explore the pattern of structural evolution. The mechanical testing results showed that the breaking
force, deformation, hardness and chewiness of surimi gels without MTGase addition (control group) increased significantly
(P < 0.05) with extended setting time. The equilibrium breaking force (1 100 g) was achieved when the setting time was 3–6 h
and the highest deformation (17 mm) was obtained in non-MTGase group when the setting time was 1–2 h, followed by a
decrease with extended setting time. The highest breaking force, hardness and chewiness were obtained when the setting
time was extended up to 3 h in MTGase group, while the deformation decreased significantly (P < 0.05) with the extension
of setting time. SDS-PAGE results showed that myosin heavy chain (MHC) content decreased with the extension of
setting time and the MHC content of the MTGase group was lower than that of the control group. The pore size of surimi
gels decreased first and then increased significantly (P < 0.05), achieving the most compact network structure when the
setting time was 3 h. Better properties of surimi gels were obtained when the setting time was 3–6 h in the absence of
MTGase or 2–4 h in the presence of MTGase at 40 ℃. To conclude, structural evolution of surimi gels can be controlled by
adjusting the setting time to obtain high-quality surimi gel products.

Key words: surimi gel, microbial transglutaminase (MTGase), structure evolution, microstructure, cross-linkage