| Summary: | 碩士 === 國立海洋大學 === 水產製造學系 === 69 ===
The studies were carried out for the purpose of tracing the denaturation in muscle proteins, deterioration in freshness and changes in freezing tolerance of frozen mackerel and amber-fish muscle during storage for a year. Fresh mackerel (scomber tapeinocephalus) and amberfish (Decapterus maruadsi) were first washed with tap-water. The whole fish were frozen to body temperature below -18℃ with an air-blast freezer (air tem-perature: -35 ℃, wind velocity: 3.0m/sec.). Subsequently all frozen fish samples were packed with folyethylene bag and stored at for a year -20℃ and -40℃ respectively. After stotuyoe for 1, 2, 3, 6, 9, 12 months samples were taken out and thawed at room temperature(25℃). The results are obtained as follows:
1.For mackerel, no significant changes in VB-N and K-value were found during first six months of frozen storage at both temp-eratures, but slowly increased in the later six months of frozen storage. For amberfish it was similar zo mackerel.
2.The extractable actomyosin of mackerel and amberfish reduced gradually during one year of frozen storage at both stored temperatures. The total activity of Ca 2+ -ATPase of actomyosin of mackerel and amberfish decreased gradually similar to the extractable actomyosin.
3.For mackerel and amberfish, no distict changes in water-holding capacity of muscle were found during the first 1-3 months of frozen storage period at both temperatures, but markedly changes were found during the later 6-12 months of frozen storage period.
4.At both stored temperatures, the amberfish muscle showed a good result in Kamaboko(fish paste) gel- forming ability through one year frozen storage. But the mackerel muscle showed a good result in kamaboko(fish paste) gel-forming ability only for first two months of frozen storage period. Then it was deteriorated during the later period of frozen storage.
5.The correlations among freshness, protein denaturation and freezing tolerance of muscle were significant under the sta-tistical analysis.
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