Effect of nano eggshell calcium on the structure, physicochemical, and gel properties of threadfin bream (Nemipterus virgatus) actomyosin

In order to explore the mechanism of nano eggshell calcium (NEC) enhancing the gel properties of surimi. The effects of NEC on the structure, physicochemical, and gel properties of myosin were investigated. The results revealed that the addition of NEC improved gel strength, storage modulus G′, and surface hydrophobicity of myosin. The maximum value was reached when the addition was 1.0 g/100 g. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the addition of NEC has a significant effect on the cross-linking of myosin heavy chain (MHC). FT-IR and fluorescence spectroscopy analysis indicated that NEC could induce the unfolding of myosin and promoted the conformational transition from α-helix to β-sheet. Scanning electron microscopy (SEM) observed that adding a moderate content of NEC (≤1.0 g/100 g) was conducive to the formation of homogeneous and dense three-dimensional network structure of myosin mixed gel. However, the addition of excessive NEC (≥1.25 g/100 g) weakened its structural properties. These results of the present study suggested that NEC has potential to be applied in surimi seafood products, and has potential applications in improving the gel structure and gel properties.