Role of Muscle Fibers in Contributing Firmness of Cooked Fish

Cooked muscle tissue of five fish species were observed by optical and scanning electron micrography. Species with firm texture had thin muscle fibers with considerable heat-coagulating material between them; species having soft texture had thick muscle fibers with little heat-coagulating material. When the cooked muscles were compressed by a Texturometer, muscle fibers of the species having firm texture slid or shifted over one another to a lesser extent than those of species with soft texture. The heat-coagulating material seemed to obstruct the displacement of the fibers. The diameter and mobility of muscle fibers are determinative of firmness of fish muscle tissue.