1992 Fiscal Year Final Research Report Summary
Studies on post-mortem change in quality of fish meat
| Project/Area Number |
02453134
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fisheries chemistry
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SAKAGUCHI Morihiko Kyoto Univ., Agric., Professor, 農学部, 教授 (00027187)
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| Co-Investigator(Kenkyū-buntansha) |
TOYOHARA H Kyoto Univ., Agric., Research Associate, 農学部, 助手 (90183079)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Fish / Muscle / Toughness / Collagen / Tenderization / Amino acid / IMP / IMP |
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| Research Abstract |
Texture and flavor are most important factors which determine the quality of raw fish meat. Muscle toughness and rigor mortis of fish body were evaluated using the breaking strength and rigor index, respectively. The breaking strength for most fish species tested was high immediately after death, and then markedly decreased 12-24h after death. Conversely, the index was low initially and increased rapidly thereafter, suggesting that the muscle toughness is independent of the rigor mortis. The loss of muscle toughness during storage was also demonstrated organoleptically.
Electron microscopic observation indicates that collagen fibers in the pericellular connective tissue were strikingly disintegrated during storage, while muscle fibers were also intact. It was suggested that post-mortem tenderization of fish muscle during chilled storage was due to the disintegration of collagen fibers in the pericellular connective tissue.
Flavor components such as free amino acids (FAA) and nucleotides in fish muscle were determined to examine the change in flavor intensity during ice storage. Little change in FAA content was observed in yellowtail muscle over 20 days of storage; ATP content decreased rapidly after about 10h in contrast to the high accumulation of IMP. All these findings indicate that the raw fish meat increased in flavor intensity in the earlier period of storage, although the toughness fell sharply.
On cooked meat, furthermore, extracts prepared from the yellowtail muscle were submitted during storage over 14 days in ice and the changes in flavor intensity were investigated. There was no detectable difference among the extracts obtained from the muscle of different storage periods, suggesting that such a compound as ATP is converted to the flavor component IMP during cooking.
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