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.