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南極オキアミ筋肉たんぱく質の利用に関する食品生化学的研究
https://fra.repo.nii.ac.jp/records/2005372
https://fra.repo.nii.ac.jp/records/2005372264caf94-d041-4f26-b34e-6892471b1538
| アイテムタイプ | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2024-05-22 | |||||
| タイトル | ||||||
| タイトル | 南極オキアミ筋肉たんぱく質の利用に関する食品生化学的研究 | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Food Biochemical Study on Utilization of Muscular Proteins in Antarctic Krill for Human Consumption | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
柴田, 宣和
× 柴田, 宣和 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Antarctic krill Euphausia superba is known as the most in quantity or the biggest in size among many kinds of krills alive in the Antarctic Ocean. It is estimated that the stock of the krill is several billion tons, and the maximum allowable catching amount of the krill is about seventy millions tons. In our country, Japan Marine Fishery Resource Research Center initiated a development on the utilization of the krill stock for human consumption, by surveying a new fishing ground from 1972, subsequently Science and Technology Agency investigated the composite study for effective utilization of the Antarctic krill stock. Recently, the Fisheries Agency organizes project teams consisting of members from goverment offices, industry and university, and conducts research with a view to developing technology on eating the krill. Hitherto the composition and properties of consituents, the healthful property and the nutritive value of Antarctic krill have been studied for the purpose of estimating the krill as a new food. However, true properties of frcsh krill muscle protein were not clarified as before, because of the distant fishing ground (Antarctic Ocean) or quick post-mortem changes of muscular protein etc. The above-mentioned matters have hindered the d:velopment of the technology for utilizing the krill as food. In this paper, the biochemical properties of muscular protein and the post-mortem changes of these properties were examined from the viewpoint of a food science, using the krill immediately after death, on board. The new information obtained in these experiments were successfully applied to the technology for the production of a new type material of food for human consumption. 1) Amout of myofibrillar protein in krill muscle and effect of digestive protease on the amount. At the beginning of research on the technology for the prodution of food material for human consumption, it was feared whether the amount of myofibrillar protein in the krill muscle was equal to that in livestock muscle and fish muscle or not. In this paper, the amount of myofibrillar protein in the krill muscle, which was prepared from the krill immediately after death, was examined considering all possible items relating to the extractability of myofibrillar protein. Consequently, the amount of myofibrillar protein in the krill muscle was confirmed to be 9.4g/100g of wet weight muscle, corresponding to several times of 1-5g/100g of wet weight muscle, shown in previous prpers. Thus, the amount of myofibrillar protein in the krill muscle bore comparison with other marine animals. However, it was recognized that the muscular protein was decomposed by protease contained in various tissues (mainly digestive organs), because of the presence of the digestive organs near the muscle under the circumstance of a small size in the case of krill. Jugding from these findings, the muscle must be obtained from the krill immediately after catching without the contamination of other tissues and then washed sufficiently with plain water; for the purpose of studying the biochemistry about the characterististics of the krill myofibrillar protein or utilizing the krill muscle for a human consumption. 2) Relation between freshness of krill and extractability of its muscular protein. The extractractability of muscular protein with the high salt concentration medium (I=0.50, pH7.3) from muscle free from digestive protease, was studied on the relation to the freshness of krill muscle. The extractable protein amounted to over 90% on the basis of total protein in the homogenate from the muscle obtained from krill immediately after death (fresh muscle). With the lapse of the storage time at 2°C, the amount of the extractable protein rapidly decreased to 50% level, and then gradually increased. A cause of the above phenomenon was estimated that the extractability of muscular protein was high owing to ATP remaining at high level in the muscle immediately after death, and then decreased concomitant with the disappearance of ATP. In addition, it was recognized that the addition of ATP in the extraction medium remarkably increased the amout of the extractable protein from the muscle of poor extractability: 3) Biochemical properties of protein extracted from fresh muscle. The amount of muscular protein extracted with I=0.50 medium and the biochemical properties of the extracted protein were remarkably influenced by the time lapsed after death of krill. Actin and myosin in the extract from the fresh muscle were estimated to be in a state of dissociating because of the presence of ATP in the extract, though the presence of actin and myosin by means of the SDS-polyacrylamide electrophoresis was affirmed. Futhermore, the protein extracted from the fresh muscle was low (or weak) in ATP-sensitivity, viscosity, Mg-ATPase, protein concentration dependency of viscosity and flow birefrigence, namely did not indicate the characteristic of actomyosin. These biochemical properties of the extracted protein were gradually changed with the lapse of time after death, and then indicated the formation of actomyosin. This phenomenon was probably caused by the disapparance of ATP contained in the muscle. 4) Examination on molecular size of extracted protein bygel filtration with Sepharose C1-4B. By gel filtration, the extracted protein was separated into three fraction ; A, B and C in order of molecular size from large to small. Two fractions (A and B) among the three fractions were judged to be actomyosin according to SDS-gel electrophore tic pattern. Most of the native actomyosin occupied only in the fresh muscle was decreased along with the storage time of the muscle, and changed to actomyosin of large molecular size (estimated as coagulate). Such change of the molecular size of the myofibrillar protein occurred in the repeated washing process of myofibrils obtained from the fresh muscle, too, Therefore, actomyosine of krill muscle was estimated to be a tendency to coagulate with ease. 5) Changes in biochemical properties and molecular size of proteins extracted from muscle stored at low temperature. In the fresh muscle, the extracted protein did not show the characteristic of actomyosin, but in the muscle stored for 2-3 days, the extracted protein maintained the characteristic of actomyosin. Hence, an irreversible denature of actomyosin did not occur during the storage periods for 2-3 days, though the actomyosin of krill muscle has a tendency to coagulate by judging from the molecular size. When the muscle was stored over 2-3 days, the biochemical properties such as ATP-sensitivity was weakened (or decreased), thereby actomyosin was clearly recognized to denature. But, the viscosity alone was kept constant for a long time, and it was not until ten days later that the viscosity decreased. On the distribution of molecular size of protein extracted from stored muscle, the actomyosin of small molecular size decreased and changed to one of large molecular size with the lapse of storage time. After 9 days' storage, most of actomyosin was that of large molecular size. 6) Characteristic of heated gel prepared from Myofibrils Fragment. The debrils of myofibrils (named Myofibrils Fragment), which were prepared from muscles of different storage times by removing the water soluble protein, were used as materials of forming a Kamaboko-like heated gel. The above biochemical properties were properly reflected in the gel strength of the heated gel. Namely, the strength was low in the initial storage period of the muscle which had the poor charactaristic of actomyosin, and high during 2-3 days' storage of the muscle which showed clearly the characteristic of actomyosin, Thereafter, the gel strength was gradually lowered and then equal to the value in the initial storage after 10-15 days of storage. The krill muscle was found able to form the heated gel having a characteristic nature (elasticity) for a long time, beyond expectation. The viscosity of the extracted protein was considered as one factor of anticipation of the ability in gel-forming, because of the apparent correlation between the viscosity of the extracted protein and the ability in the gel-forming. The optimum conditions of preparing the heated gel from Myofibrils Fragment of the krill muscle resembled to the case of the deep-sea fish requiring the extreme low-temperature treatment or short time setting (suwari), which was different from high-temperature (about 30℃) setting generally performed in the case of fish muscle. However, the gel strength after heating was comparatively strong, the Myofibrils Fragment prepared in this time exhibited excellent quality as a food. Moreover, this heated gel retained the noticeable characteristic as a new material of food, which had considerably different properties such as high in moisture and depression compared with the frozen surimi prepared from the krill muscle. | |||||
| 言語 | en | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 我国において,南極オキアミEuphausia superba の食用技術開発の研究が1972年より開始され,この間に,南極オキアミの新食品としての事前評価を目的として,構成成分の組成と性状,安全性と栄養価等の研究がなされた。しかし,オキアミたんぱく質の性状については,漁場が遠く,死後変化が速い等の制約があって,漁獲直後の本来の性状は依然として不明の点が多く,利用技術開発上の大きな障害となっていた。著者は南氷洋上において極めて新鮮なオキアミを用い,食品学的な観点から筋肉たんばく質の生化学的特性とその死後変化を詳細に検討し,従来知られていなかった新知見を得,これらの知見を食用化技術に活用して新しい食品素材の開発に成功した。1) 筋肉中の筋原繊維たんばく質量と消化器管ブロテアーゼの影響 オキアミの食用化技術開発研究が開始された当初は,オキアミの筋肉中には畜肉や魚肉に匹敵するほどの筋原繊維(Mf)たんばく質量が果たして含まれているか,どうかが懸念されていた。本研究では,漁獲直後の新鮮なオキアミ筋肉を用い,Mf たんぱく質の抽出性に影響を及ぼす要因に対して十分に検討配慮した結果,Mf たんぱく質量は従来の報告中で見られる 1-5g/100g 筋肉に比べて数倍に及ぶ9.4g/100g筋肉であることを確認した。このように,オキアミ筋肉中には他の水産動物に比べて遜色のないMfたんぱく質量が含まれていたが,オキアミの魚体は非常に小さいため,筋肉とプロテアーゼを含む他の組織(主に消化器官)が近在しており,筋肉たんぱく質に対してブロテアーゼが作用しやすい状態にあることも事実として認められた。したがって,Mf たんばく質の特性に関する生化学的研究を行う場合はもとより,オキアミ筋肉を食品として利用する場合においても,漁獲後直ちにできるだけ他の組織が混入しないように採取した筋肉を素材とすることが重要であり,しかも得られた筋肉を十分に洗浄する必要があることを知った。2) 生鮮時の筋肉たんばく質の抽出性 消化器管プロテアーゼの影響をほとんど受けないように精製した筋肉を用い,そのたんぱく質の抽出性について検討した。その結果,高塩濃度(I=0.50)溶媒によるオキアミ筋肉たんぱく質の抽出性は,即殺直後の筋肉では非常に高いが死後の時間経過とともに急減し,数時間で即殺時の約50%まで減少し,その後徐々に回復増加した。この原因はおそらく即殺後の筋肉にはまだATPが存在しているために抽出性が高く,ATPが分解消失すると低下するものと推定された。この推定を確める意味で,抽出性が低い筋肉からたんぱく質を抽出するに際して,I=0.50 の塩溶媒に ATP を添加したところ,抽出性は回復上昇した。3) 生鮮時の筋肉から抽出したたんぱく質の生化学的性質I=0.50の塩溶媒による筋肉たんぱく質の抽出量は死後の時間経過(鮮度)によって大きく変化し,また抽出たんぱく質の生化学的性質も著しく異なった。すなわち,即殺後の筋肉から抽出したたんぱく質溶液には,ATP が含まれているため,その SDSーゲル電気泳動図によるとアクチンとミオシンが含まれてていると判断されるにもかかわらず,両成分は抽出溶媒中で解離した状態に保たれていると考えられた。すなわち,この抽出たんぱく質はATP感度および粘度が低く,異状粘性も示さず,Mg-ATPase活性および流動複屈折性が弱く,いわゆるアクトミオシンとしての特性がみられなかった。しかし,死後の時間経過にともない,この抽出たんぱく質の生化学的諸性質は次第に変化して,アクトミオシンが形成されたことを示した。この現象はおそらく,筋肉中の ATPが分解消失したことにより起こるものと考えられる。4) Sepharose C1-4B を用いたゲル沪過法による抽出たんばく質の分子サイズの検討 オキアミ筋肉から抽出したたんぱく質はゲル沪過法によって,分子サイズの異なる3画分に分画されたが,その中の2つの画分は SDSーゲル電気泳動図からみて,いずれもアクトミオシンと判断された。生鮮時の筋肉中に多量に含まれる native(未変性)のアクトミオシンは,筋肉の貯蔵の時間経過にともなって減少し,分子サイズの大きいアクトミオシン(凝集体と推定)に変った。このようなMfたんぱく質の分子サイズの変化は新鮮な筋肉から得たMfを繰り返して水洗する過程でも起こり オキアミ筋肉のアクトミオシソが非常に凝集しやすいこと示唆している。5) 低温貯蔵中の筋肉から抽出したたんばく質の生化学的性質と分子サイズの変化 貯蔵初期の新鮮筋肉から抽出したたんぱく質はアクトミオシンの性質を示さないが,2-3日間貯蔵した筋肉から抽出したたんぱく質は典型的なアクトミオシンの特徴を有していた。したがって,分子サイズの面からみればオキアミ筋肉のアクトミオシンは凝集しやすいが,この貯蔵期間中には,まだ不可逆的なアクトミオシンの変性は起きていないと考えられる。筋肉の貯蔵がより長期にわたると,抽出されるたんぱく質のATP感度等の生化学的諸性質が弱まるかあるいは低下し,アクトミオシンの明らかな変性が認められた。しかし 粘度だけは依然として高い値を保ち,貯蔵10日目以降にはじめて低下した。この間の抽出たんぱく質の分子サイズの分布をみると,分子サイズの小さいアクトミオシンが減少し,分子サイズが大きい画分へと移行した。6) Mf 画分より調製した加熱ゲルの特徴貯蔵時間の異なる筋肉から水溶性たんぱく質を除いて収集した“Mf画分”からかまばこ様の加熱ゲルを調製したところ,そのゲル強度は上述の生化学的性質をよく反映しており,アクトミオシソの性質の弱い貯蔵初期では低く,アクトミオシンの性質が高まった貯蔵2-3日間が最も高いゲル強度を示した。その後,ゲル強度は次第に低下し,10-15日間後は再び貯蔵初期の程度にまで低下したが,オキアミ筋肉は予想外の長期間にわたり,ある程度のゲル強度を有する加熱ゲルを形成することが知られた。この結果は比較的長期間にわたり高い値を示した粘度と見かけ上相関しており,抽出たんぱく質の粘度はゲル形成能を推定する指標のひとつとなるように考えられた。なお,オキアミ筋肉のMf画分から加熱ゲルを調製する最適条件は深海魚の場合とよく似ており,極端な低温管理と短時間の坐りを必要とし,この点,普通の魚類筋肉にみられる高温坐り(30℃前後)の特性とは異なっていた。しかし,加熱後のゲル強度は比較的強く,得られたMf画分はすぐれた食品性状を示した。また,この加熱ゲルは同じオキアミ筋肉の冷凍すり身からのかまぼこゲルに比べて,水分含量が高く,押し込み荷重に比べて凹みが非常に大きいなどの点で著しく異なった性状を示し,新しい食品素材として注目される特性を有していた。 | |||||
| 言語 | ja | |||||
| 書誌情報 |
ja : 東海区水産研究所研究報告 en : Bulletin of Tokai Regional Fisheries Research Laboratory 巻 111, p. 63-141, ページ数 79, 発行日 1983-08-25 |
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| 出版者 | ||||||
| 出版者 | 東海区水産研究所 | |||||
| 言語 | ja | |||||
| 出版者 | ||||||
| 出版者 | Tokai Regional Fisheries Research Laboratory | |||||
| 言語 | en | |||||
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| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 0040-8859 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00156834 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | tokai_k_111_63 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010281807 | |||||
| 言語 | ja | |||||
| 関連名称 | 日本農学文献記事索引(agriknowledge) | |||||
