Myofibrillar protein conformation enhance gel properties of mixed surimi gels with Nemipterus virgatus and Hypophthalmichthys molitrix

Abstract Marine and freshwater fish surimi exhibit a synergistic effect when mixed in a suitable ratio. In this paper, we investigated changing in myofibrillar protein conformation enhance the properties of mixed surimi gels formed by thermal processing. The mixtures of Nemipterus virgatus and Hypophthalmichthys molitrix surimi were prepared (N:H mass ratios of 0:1, 1:0, 3:1, and 1:5) and analyzed during thermal processing. In particular, changes in gel properties, microstructure, and protein conformation during gel formation were studied. The obtained results show that heating increases the fracture constant of the 3:1 and 1:5 surimi mixtures from 143.64 N/m and 68.40 N/m to 442.78 N/m and 320.99 N/m, respectively, and the fracture constant of the 1:0 and 0:1 surimi from 87.07 N/m and 56.71 N/m to 443.18 N/m and 237.42 N/m, respectively. Similarly, the water holding capacities, whiteness values, β-sheet, β-turn, and disulfide bond contents of these two gels increase with increasing processing time at 40 then 90 °C. Meanwhile, nonspecific association, hydrogen bonding, and α-helix contents in the N:H = 3:1 and N:H = 1:5 samples decrease under the effect of thermal processing. Microstructural images show that the network structure of the mixed surimi gel is tighter and more compact than that of the single-component gels. Based on these results, the synergistic effect is induced by the interactions between proteins from different sources in a suitable ratio.