Improved texture properties and toughening mechanisms of surimi gels by double network strategies

Surimi gels with improved texture attributes are highly populated by customers. In this study, the double network strategies were applied to tailor gel properties of surimi, and the corresponding mechanisms were also emphasized. The double network (DN) surimi gels are obtained by covalent cross-linking roles of TGase and non-covalent interactions of curdlan with myofibrillar protein, respectively. The results suggested that the tunable brittleness/elasticity of surimi gels can be achieved by adjusting TGase and curdlan proportions. TG/C2 DN surimi gel (0.4%TGase and 1% curdlan) shows the high fracture strain/stress and gel strength, compared to other SN gels. Besides, the DN surimi gels always show the relatively high WHC, due to the formation of ordered network of surimi gels. According to results from LF-NMR relaxation and MRI images, the DN surimi gels restrict the water migration, confined by the multi-hierarchical network. TG/C2 group has the energy dissipation value of 13.26, significantly higher than the control group (6.33) and TG (9.62) or curdlan (8.64) SN gels. Thereafter, the high energy dissipation and network entanglement of DN surimi gels contribute to improving the gel properties of surimi. This work provides some constructive inspirations for the development of surimi gels products with the tailored and toughening texture properties.