Changes of impedance at 2 kHz, muscle contraction and ATP content in cultured yellowtail were measured during 0 (ice), 5, 10, 15, 20 °C storage, and histological changes were analyzed by light microscope during ice storage. The relative impedance at each temperature increased during early storage and then deceased, while each muscular contractile percentage increased with ATP consumption. The increasing speed of relative impedance was synchronous with the increasing speed of muscle contraction at any storage temperatures, and their increasing speeds were followed by 0°C ≒ 20°C > 5°C > 10°C > 15°C. In addition, the narrowed and expanded intercellular spaces were respectively observed at 4 h and at 20 h, which were accompanied by the development of muscle contraction and impedance. These results suggest that the temporal rise in impedance during early storage has a significant relationship with rigor mortis and narrowing of intercellular space.
