The purpose of this study is to elucidate the relationship between food histological structures and structural components in cooked chicken meat of Cochin (Nagoya-Cochin; Nagoya Breed). The results obtained were summarized as follows; 1) Significant differences could be admitted in breaking strength between two different kinds of cooked dark meat: Cochin and broiler after 24hrs post-mortem storage at 4°C.2) There were no differences in water holding capacity by pressure in raw dark meat between Cochin and broiler. On the other hand, there were significant differences in cooking loss and water holding capacity by heating and then pressure.3) There were no differences in 5'-inosinic acid (IMP) content and glutamic acid content in dark meat and also soup prepared from dark meat between Cochin and broiler on both after 24hrs post-mortem storage at 4°C.4) In the light microsccpy, the structures of raw dark meat in the both species that had undergone frozen storage showed wide gap of the muscle fiber.
Especially, the cross section of the muscle fiber of 8 weeks old broiler occasionally showed round shaped contour and amorphous cytoplasm. These observations had not recognized in the fresh broiler that had not undergone frozen storage by the same fixation. The cooked dark meat in the both species had been characterized by small red granules in the inter-fiber-space in the Masson's trichrome stain section, and had not shown reticular fibers network. These phenomena were more marked in the specimens of frozen and then cooked broiler. The cooked dark meat of 8 weeks old broiler clearly indicated above observations than in Cochin. In the electron microscopy, the cleft was observed under the cell membrane of the muscle cell in the frozen tissue in both species. It was suggested that the cleft was made by growing ice-crystal under the cell membrane. It was an interesting finding that the I-band of the muscle-fiber in the cooked dark meat was composed of triad band showing light-dark-light electron density.
