• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.912-913
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• 1996

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.589-594
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• 1997

This study was performed to clarify the effect of anesthesia killing and non-bleeding on the physicochemical and rheological properties of plaice, Paralichthys olivaceus muscle at early period after death. Live plaice was killed by the two different methods: spiking at the brain instantly with bleeding and dipping In seawater containing anesthetic (2,000 ppm ethyl-aminobenzoate) for 10 min without bleeding. These samples were stored at $0^{\circ}C$ and used in checking rigor-mortis, ATP breakdown, the content of ATP and its related compounds, breaking strength, and lactate accumulation through storage. The rigor-mortis, ATP breakdown, and lactate accumulation was faster in samples killed by spiking than in samples killed by anesthesia. ATP in samples killed by anesthetic showed little breakdown until 22.5 hrs, but it was decomposed completely after 30 hrs storage. Breaking strength of samples killed by spiking at the brain instantly with bleeding decreased steadily and showed the maximum value over 10 hrs $(2207.3{\pm}60.2g)$. However, in case of the dipping fresh flesh without bleeding in seawater containing anesthetic, the value and time reached around the maximum breaking strength were $2147.8{\pm}29.0g$ and 13 hrs respectively, but it maintained constantly until 20 hrs passed. From these results, it could be suggested that anesthesia killing and non-bleeding is more effective in maintaining firmness of fresh plaice muscle than spiking killing with bleeding at the early period after death.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.523-528
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• 1998

To clarify the effect of life or death condition before cooling on the physicochemical properties of plaice, Paralichthys olivaceus muscle at the early period after death, the plaices were dipped in the refrigerated sea water ($0^{\circ}C$) either as alive or after anesthesia killing. These samples were stored at $0^{\circ}C$ sea water and the changes in rigor-mortis, ATP breakdown, content of ATP and its related compounds, breaking strength and lactate accumulation through storage were investigated. Acceleration of rigor-mortis, ATP breakdown and lactate accumulation were taster in the samples refrigerated as alive than in samples killed by anesthesia before cooling. ATP in samples refrigerated as alive showed little breakdown until 7.5 hrs but it was decomposed completely after 17.5 hrs storage. The breaking strength in muscle of plaice was 1736.2 $\pm$ 65.4 g immediately after killing. The breaking strength in samples dipped in refrigerated sea water as alive increased more rapidly and showed the maximum value over 7.5 hrs (2183.3$\pm$32.2 g), However, in case of samples killed by anesthesia before cooling, the value and time reached around the maximum breaking strength were 2126.3 $\pm$ 32.2 g and 12.5 hrs, respectively and then decreased until 30 hrs. From these results, it could be suggested that dipping in refrigerated sea water after anesthesia killing before cooling is more effective in maintaining freshness of fresh plaice muscle than refrigerating as alive.