Comparison of four different freezing techniques about the preservation effects on yellowfin tuna

In this paper, it was studied about the preservation effect of four freezing technique, liquid nitrogen freezing, refrigerant freezing, -80℃ freezing and-18℃ freezing, on the dorsal muscle of yellowfin tuna by determining the K value, TBA value, TVB-N value, met-myoglobin content, chromatic aberration and by sensory evaluation. The results showed that:the K value, TBA value, TVB-N value and met-myoglobin content of tuna meat frozen by liquid nitrogen were all lower than the other three freezing techniques, and liquid nitrogen freezing method could keep tuna meat fresh for a longer time. So from this perspective, liquid nitrogen freezing technique was the best among these four freezing methods. But unfortunately, there were some slight cracks on the surface of samples frozen by liquid nitrogen because of the fast freezing speed, so its chromatic aberration and score of sensory evaluation were poor than that of samples frozen by refrigerant.