Burnt meat or spontaneously done meat ("yake-niku" in Japanese), which is accompanied by meat quality deterioration such as whitish discoloration, decrease in water holding capacity, etc., occurs frequently to tunas, especially during the summer season. However, the mechanism behind this phenomenon has not yet been fully explained. So far there has been no objective criterion to evaluate the extent of tuna meat deterioration. In order to elucidate the properties of burnt meat in cultured and wild bluefin tuna, differences in the meat quality (met-myoglobin formation ratio, myoglobin content, color difference values) and water-soluble (sarcoplasmic) protein components in the ordinary (white) and dark muscles were compared between normal and burnt fish. The data obtained showed that aggregation and decomposition of protein components took place in the burnt meat. Since some components, such as creatine kinase in the ordinary muscle, were absent in the burnt portion irrespective of whether the fish was wild or cultured, they were found to be excellent markers to distinguish burnt fish from normal fish. On the other hand, the extent of changes in myoglobin was quite small based on the data of solubility and calorimetric analysis, suggesting that this protein is not largely involved in discoloration of burnt portions.
ASJC Scopus subject areas
- Aquatic Science