The Phenomenon of Frozen Yellowtail Muscle by Liquid Nitrogen Freezing

Abstract

We aimed to investigate the de-oiling phenomenon of yellowtail on freezing using liquid nitrogen (LN2). The yellowtail samples were frozen at -30 °C (stationary freezing, SF) or soaked in LN2 to observe the de-oiling phenomenon. The thawed samples were left on a paper plate at 25 °C for 10 h. As a result, it was observed that the LN2 frozen sample was de-oiled more than the sample of SF. The raw yellowtail was frozen in a stocker at -30 ℃and soaked in LN2. The water and oil loss were obtained on thawing under running water the frozen yellowtail and stored at 10 ℃ or 25 ℃ for 18 h. The drip loss immediately after thawing was 0.4% lower in the sample with LN2 freezing. On the other hand, the drip loss of the LN2 frozen sample was higher than the frozen sample in SF after storage at 10 °C and 25 °C. After storage at 25 °C, the water loss was 7.6%, the oil loss was 5.5% in the LN2 frozen samples, which was significantly higher. From the results, we found that the amount of drip loss, especially the outflow of lipids, increases during storage after thawing.