Nano eggshell calcium enhanced gel properties of Nemipterus virgatus surimi sausage: gel strength, water retention and microstructure

Summary The effects of nano eggshell calcium (NEC) at different levels (0–1.5 g/100 g) on the gel properties of Nemipterus virgatus surimi were investigated. The results indicated that under the condition of adding 1.0 g/100 g, the gel strength of surimi was the highest, the water‐holding capacity (WHC) was the best, and the cooking loss was the lowest. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS‐PAGE) revealed that the addition of NEC promoted the covalent cross‐linking between myosin heavy chains (MHC). Raman spectroscopy demonstrated that low contents (0.5–1.0 g/100 g) of NEC promoted the conformational transition of surimi protein from α‐helix to β‐sheet. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) showed that the surimi gel with 1.0 g/100 g NEC had a denser network structure. Nevertheless, in the mixed gel with 1.25–1.5 g/100 g NEC, the network structure of the mixed‐protein matrix was disrupted, and the mechanical and physicochemical parameters were deteriorated.