Microstructure of Fish Meat Emulsion with Addition of Egg-Yolk

抄録

Fish meat emulsion was prepared from egg-yolk, very low-lipid sardine meat (which was prepared through grinding or suspending in weak alkaline solution), salad oil, and vinegar. The microstructures of the oil droplet surface and myofibrillar matrix were investigated. By Polytron homogenization, the myofibrils were shattered to a much smaller size in ground-meat emulsion, according to the original smaller fragment size. The network structure was formed by the myofilaments spread apart from the shattered myofibrils in the fish meat emulsion. The mesh size of this structure was smaller in the ground-meat emulsion than in the suspended-meat one and corresponded to the oil droplet size. In the suspended-meat emulsion, the oil droplet size was smaller at oil ratio 1.1 to sardine meat than at the ratio 1.6. In the non-fish conventional emulsion, the viscosity increase due to the dispersion of oil droplets to the egg-yolk matrix was not sufficient to prevent irreversible shear breakdown induced by coalescence. In fish meat emulsion, the network structure made of myofilaments showed a remarkable increase in viscosity and held the oil droplets tightly during the application of high shear rates to prevent the coalescence and exhibit a weak trend of thixotropy.