Gel strengthening effect of zinc salts in surimi from yellow stripe trevally

•Zinc salts at an appropriate level could increase gel strength of surimi.•ZnSO4 showed the higher gel strengthening effect than ZnCl2.•Addition of zinc salts increased whiteness of surimi gel.

Effects of zinc sulphate (ZnSO4) and zinc chloride (ZnCl2) at various levels (0–80 µmol/kg) on the properties of gels from yellow stripe trevally (Selaroides leptolepis) surimi were investigated. Both kamaboko (40/90 °C) and modori (60/90 °C) gels added with ZnSO4 or ZnCl2 up to 60 µmol/kg had the increases in breaking force and deformation (P<0.05), compared with the control. The higher breaking force and deformation were generally found in kamaboko gels added with ZnSO4, compared with ZnCl2 (P<0.05). Whiteness of both kamaboko and modori gels increased with increasing levels of zinc salts (P<0.05). Salt bridge and ionic interactions played a major role in cross-linking of proteins. Kamaboko gel had highly interconnected, denser and finer network with smaller voids when zinc salts, especially ZnSO4 at 60 µmol/kg, was incorporated. Therefore, ZnSO4 at an appropriate level could improve gel strength and whiteness of surimi from dark fleshed fish.