Partial Freezing as a Means of Keeping Quality of Sea Foods 1. Keeping Quality of Baked Mackerel Muscle during Partially Frozen Storage

빙결점동결에 의한 수산식품의 품질보존에 관한 연구 1. 빙결점동결 저장 중의 구운 고등어의 품질변화

As a new practical method for preserving freshness of fish, partially frozen storage has been reported to be useful in terms of K-value, TBA value, sensory evaluation etc. In order to develop a storage procedure to be used in place of cooled or frozen storage for the preservation of precooked fish food, partial freezing for up to two to three weeks was examined using baked mackerel. The criteria for evaluation were made according to the changes in volatile basic nitrogen (VBN), thiobarbituric acid (TBA) value, viable bacterial number, pH, color difference and sensory evaluation in fish muscle. The changes in TBA value of baked muscle during storage at $-3^{\circ}C$ differed slightly from those obserbed during cooled ($5^{\circ}C$) and frozen storage ($-20^{\circ}C$). Partial frozen storage ($-3^{\circ}C$) was effective in prolong an induction period of lipid oxidation during early storage. VBN of baked muscle tends to increase slowly while pH value was decrease during storage and there was no observed significant differences among three different storage condition. Viable bacterial number of the baked mackerel muscle stored at $-3^{\circ}C$ showed significantly less than that stored at $5^{\circ}C$, and similar to that stored at $-20^{\circ}C$ (the levels of $10^2/g$). Judging from the results of sensory evaluation and experimental data, partial frozen storage at $-3^{\circ}C$ seems to be effective as means of short-period preserving baked mackerel.

어육을 단기간 저장하는데 효율적인 저장방법으로 알려진 빙결점동결법을 조리식품에 적용하여 저장중의 품질안정성에 대하여 실험한 결과를 요약하면 다음과 같다. 빙결점동결법으로 저장한 구운 고등어는 지방의 산패면에서 $5^{\circ}C$ 및 $-20^{\circ}C$에서 저장한 것보다 유도기가 약간 연장되는 효과가 있었으며, pH와 VBN는 세가지 저장조건에 따른 큰 차이가 없었다. 저장중 pH는 약간 감소하는 반면 휘발성염기질소는 저장초기에 급증하고 저장 4일 이후에는 큰 변화가 없었다. 생균수는 빙결점동결법으로 저장한 것이 $5^{\circ}C$ 저장한 것보다 상당히 낮은 값을 나타내었으며, $-20^{\circ}C$에서 저장한 것과 비교하여 큰 차이가 없었다. 그리고 관능검사의 결과도 빙결점동결법으로 저장한 것은 $-20^{\circ}C$에서 저장한 것과 비교하여 큰 손색이 없었다.