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凍結‐貯蔵タラ肉におけるスポンジ化の生成機構とその防止
https://fra.repo.nii.ac.jp/records/2005330
https://fra.repo.nii.ac.jp/records/2005330ceba3859-8dba-4a74-a154-1a461650b077
| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2024-05-22 | |||||
| タイトル | ||||||
| タイトル | 凍結‐貯蔵タラ肉におけるスポンジ化の生成機構とその防止 | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | Studies on the Condition and the Mechanism Related with the Spongy Meat Formation in the Frozen Cod and its Preventive Treatments | |||||
| 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 |
田中, 武夫
× 田中, 武夫 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The so-called cod fish in Japan implies two kinds of fish (cod, Gadus macrocephalus TILESIUS and Alaska pollack, Theragra chalcogramma (PALLAS)), and is caught in abundance by Japanese fishing boats. The amount of catch of these two fish has increased in recent years and it was 440, 000 tons in 1959 which ranked No. 4 in the amount of catch by kind of fish. They are caught by inshore fishing of Hokkaido as well as by pelagic fishing in northern sea very far from the large consuming markets in Japan. The meat of these fish always suffers very adverse change by freezing preservation, because the meat usually converts to very porous and tough texture when defrosted so that it loses quality as a food commodity. This change is well known as the spongy meat of cod among the fishery and the freezing industry people in Japan. Due to this, the cod fish is commonly preserved by icing and it is very rere to use freezing preservation in Japan. So it is very difficult to maintain a smooth supply of fresh cod fish as demand requires it in Japan and overseas. This research is aimed to clarify the mechanism involved in the spongy meat formation which causes fatal damage to the defrosted cod meat, by means of systematic and physical examination of the phenomena concerned and eventually to find some practical means effective in protecting the cod meat from such a loss caused by freezing. I. From observations of spongy meat of cod fish by means of naked eye, microscope and chemical measurement and also by study pursuing to know the development of the spongy texture change during one year frozen storage at -20°C after freezing the cod fish by the coil-shelf system air freezer room which is the most prevalent freezing process in Japan, the author came to the conclusion that the formation of spongy meat was closely related to two factors as follows: 1. Decrease of water holding capacity accompanied with the progress of protein denaturation in muscle fiber during freezing and frozen storage resulting in free water increase. 2. Water migration from muscle fiber toward outside and its extra-fiber freezing. II. Generally it is said that the quality of frozen food depends on the parameters such as freezing velocity, storage temperature, and conditions in prefreezing treatment such as freshness of fish, treatment and shape. Therefore it was critically studied how these parameters affect the two factors above mentioned - decrease in water holding capacity and migrated water freezing outside the muscle fiber. It was eventually found that thereoccurs migration of water not necessarily originating in the denaturation and decrease of water holding capacity of the protein and that this kind of water plays a greater part in the change of spongy texture of cod meat. This finding will be basic and scientific information which is very useful to improve the conventional freezing and freezing preservation practice of cod fish from raw material to freezing preservation, because so far only fragmental research information on the cod fish freezing has been available. III. From the findings mentioned above, the mechanism of spongy meat formation in cod meat seemed to be identified by a cross examination of the mechanism associated with water migration and its extra-fiber freezing, that is to say it is very important to know, if there is some characteristic property in the cod meat which helps the migration of water to freeze outside the muscle fiber. Therefore a comparative survey of frozen fish meat in respect to the spongy meat formation was carried out between cod fish and various kinds of other fish and the following results are obtained. (1) Comparing the specific gravity of the meat soon after being frozen, cod meat showed a much smaller value than the various kinds of other fish such as young yellowtail (Seriola quinqueradiata TEMMINCK et SCHLEGEL), chub mackerel (Scomber japonicus HOUTTUYN), horse mackerel (Trachurus japonicus (TEMMINCK et SCHLEGEL)) which means that the rate of freezing expansion of meat is fairly bigger in the cod meat than in the other fish. And by further study to find out the reason why the cod meat had a larger rate of expansion, following facts of cod meat were disclosed. 1. Cod meat always shows a high rate of water content more than 80%. 2. Ice crystal produced by freezing in muscle fiber contains very fine free gas bubbles that is never seen in raw meat before freezing because freezing liberates dissolved gas from liquid fraction in muscle fiber. And we are convinced that these two characteristic facts are the factors assistingthe migration of water and its freezing in extra-fiber region. And yet it is ascertained that cod fish caught in different seas showed different extent of spongy meat and that cod fish in northern sea suffers less spongy meat than in southern sea. The reason for this difference will be justified by the fact that the water content of the cod meat from northern water is less than that from southern water. According to gas chromatography analysis, it is indicated that the free gas in the ice crystal consists of O₂ 16% and N₂ 84% in mol % which was dissolved in the liquid fraction in muscle fiber and liberated as free gas from it during freezing of muscle fiber. The liberated gas expands to volume causing high pressure gas which seems to accelerate squeeze out of unfrozen water from the muscle fiber and furthermore during freezer storage high pressure gas remaining in the muscle will exclude the water vapour produced by the ice crystal sublimation there. A new theory like this on the formation of ice crystal is a modification and enlargement of the classic theory established by Dr. PLANK. This new theory will be supported by the result obtained in the fish meat freezing experiments of other fish kinds such as alfonsino (Beryx splendens LowE), Japanese bluefish (Scombrops boops (HOUTTUYN)), angler fish (Lophius sp.) and devil stinger (Inimicus japonicus (CUVIER)), as these fish meats become a spongy texture liberating free gas which is similar to the cod meat when they were frozen. There are some comments on the physiological significance of the gas dissolved in these bottom fish meat. (2) Furthermore by means of electron microscope observation to find characteristic feature of cod meat, it was detected that there are very small tiny pores in the muscle fiber membrane which seem likely to facilitate the water squeeze out from the muscle fiber. And also it was found that in spongy meat of cod fish, there is toughened muscle fiber membrane which is surely associated with the hardening of frozen cod meat. IV. From the data obtained in this experiment, it was discussed how to prevent the spongy texture formation in the cod meat always experienced in commercial freezing system and some suggestions were made on the pratcical prevention. Thus it was demonstrated that dehydration of cod meat by drying or compression method and exhausting gas under reduced pressure or gas-free-water soaking are fairly effective means as a process before freezing and particularly either compression or water soaking is very useful. Besides it was evidenced that the low temperature storage at -30℃ after air blast freezing is good enough to protect the cod meat from the spongy txture development. In view of the successful result in this research on cod meat freezing preservation, floating factories of trawl fishing boats fleet are going to install quick freezing apparatus by air blast system or contact plate freezer as well as low temperature freezer storage hold below -25℃ while dehydration process of cod meat before freezing is now under discussion. | |||||
| 言語 | en | |||||
| 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 116, p. 67-224, ページ数 158, 発行日 1985-03 |
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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 | |||||
| ISSN | ||||||
| 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_88 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010323577 | |||||
| 言語 | ja | |||||
| 関連名称 | 日本農学文献記事索引(agriknowledge) | |||||
