部分 凍結과 魚肉의 鮮度

Partial freezing and Freshness of Fish

가물치, 꽁치, 삼치, 말쥐치, 숭어 등 5종의 활어 또는 신선어의 근육에 있어서, 0℃ 및 -5℃로 partial freezing중, k값과 아미노태질소 및 TBA 값 변화에 관한 실험을 하였다. -5℃에서 k값 변화는 0.9~1.1이었으며 0℃에서는 3.1~10.6으로, -5℃에서의 k값 증가율이 훨씬 낮았고 또한 혈합육을 함유한 것이 k값이 흰살육 보다 대체로 높은 편이었다. -5℃에서 아미노태질소 변화율은 2.3~21.3㎍/day이었으며 0℃에서는 4.0~42㎍/day으로, 역시, -5℃에서의 증가율이 낮게 나타나 단백질 분해속도가 partial freezing시 늦었으나 k값에 대한 저해효과보다는 크지 않았으며 또한 혈합육이 흰살육 보다 안백의 가수분해율이 높았다. TBA 값은 말쥐치의 경우, -5℃ 보다 0℃에서 높았던 반면 삼치는 -5℃에서 높게 나타나는등, 어종에 따라 TBA 값의 변화율이 서로 달라 일정한 차이를 나타내지 못하였다.

The experiments were carried out to obtain information on the freshness for the changes of k-value, NH₂-N and TBA value in fish muscle during storage at low temperature. The sample used for this experiments were 5 species, Snake head, Saury, Spanish mackerel, File fish and Mullet. Then the change of fish muscle in quality was observed in case of the partial freezing (-5℃) and the ice storage (0℃) respectively. The rate of change in the k-value was showed 0.9~1.1 during storage by the partial freezing and 3.1~10.6 by the ice storage. The increasing rate of k-value was slow in the partial freezing than in the ice storage and the rate higher for white fleshed fish than for dark fleshed fish. The rate of change in the NH₂-N was showed 2.3~21.3μg/day by the ice storage. The protein degrading speed was slow in the partial freezing than the ice storage and was not remarkable. The changing rate of TBA-value did not keep a regular difference according to the kinds of fish.