Shiokara - Shiokara

A food made by adding salt to the flesh, innards, and eggs of fish and shellfish to preserve them, and ripening them through the action of enzymes contained in the ingredients or added from elsewhere. Ingredients include squid, sea urchin, sweetfish and their innards, bonito and abalone innards, sea cucumber intestines, salmon kidneys, mackerel ovaries, sea squirts, shrimp, and fiddler crabs. It is thought to have developed from the salting method that has existed since prehistoric times and become a type of dish, and in the Nara period, the imperial court used shishibishio (meat sauce) made by salting and fermenting the flesh of birds, animals, fish, and shellfish. It is the equivalent of shiokara in later times. In the Manyoshu, there is a song about making crab paste, titled "A song that describes the pain of the crab." In the Heian period, there were various kinds of shiokara, such as "deer mash," "rabbit mash," and "fish mash," and they were transported from various provinces to the capital as tributes or trade goods. Salted sweetfish (uruka) and salted sea cucumber intestines (konowata) were already being made in this period.

Fish and shellfish, especially their innards, contain enzymes such as trypsin, a proteolytic enzyme, amylase, and lipase. These enzymes act on the proteins, carbohydrates, and lipids in the ingredients, converting them into simpler structures. As a result, peptones, peptides, organic bases, glucose, lactic acid, etc. increase, and in the next stage, amino acids are produced, increasing the umami flavor. This process of developing a different umami flavor from the ingredients during storage is called maturation. The addition of rice koji (komekoji) to shiokara made from squid, bonito, etc. increases the umami flavor, because the enzymes produced by the koji help the shiokara to mature, and the amylase produced by the koji acts on the rice starch to produce maltose and glucose, increasing the sweetness. It is said that enzymes produced by the bacteria, yeast, and other microorganisms that grow in the shiokara also play a role in the maturation of shiokara. The types and numbers of microorganisms that grow in the shiokara depend on the salt concentration, but when the salt content is around 10%, the types and numbers of microorganisms are naturally greater than when 20% salt is added. This causes the shiokara to mature faster. On the other hand, adding 20% ​​salt makes it difficult for microorganisms to grow, and reduces the contribution to ripening. Recently, consumers have become reluctant to consume too much salt due to fears of high blood pressure, so less salt is being added to shiokara, and since salt alone is not enough to prevent spoilage, it must be stored in the refrigerator.

In terms of nutrition, it is easy to digest because the animal protein is in a somewhat digested form, and it is highly nutritious, but it has the disadvantage that it contains 10% salt, which can lead to excessive salt intake.

The largest amount of production is salted squid (white, red, black, etc.), at about 3,000 tons, followed by salted sea urchin at 1,500 tons. The total amount of other products is about 2,000 tons, and many of them have become local specialties. They are also used as a snack with sake or as a rice dish, but production is stagnant.

[Kaneda Hisashi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

魚貝類の肉、内臓、卵などに食塩を加えて保存性をもたせるとともに、原料中に含まれる酵素または他から添加した酵素の作用により熟成させた食品。材料はイカ、ウニ、アユとその内臓、カツオやアワビの内臓、ナマコの腸、サケの腎臓(じんぞう)、サバの卵巣、ホヤ、アミ、シオマネキなど。原始時代からあった塩蔵法が発達して料理の一種となったものと考えられ、奈良時代には鳥獣魚貝の肉を塩漬け発酵させた醢(ししびしお)（肉醤）が朝廷でも用いられていた。後世の塩辛にあたるものである。『万葉集』には「蟹(かに)のために痛(おも)ひを述べて作れる歌」として、カニの醢をつくるようすを歌ったものがある。平安時代には、「鹿醢」「兎醢」「魚醢」などがあり、種々の塩辛の類が調(ちょう)や交易雑物として諸国から都へ運ばれていた。アユの塩辛（うるか）、ナマコの腸の塩辛（このわた）はすでにこの時代からつくられていた。

　魚貝類とくにその内臓にはトリプシンとよぶタンパク質分解酵素やアミラーゼ、リパーゼなどの酵素が含まれている。これらの酵素は原料中のタンパク質、炭水化物、脂質に働き、これを簡単な構造のものへと変える。その結果、ペプトン、ペプチド、有機塩基、ブドウ糖、乳酸などが増え、さらに次の段階ではアミノ酸を生じうま味を増す。このように貯蔵中に原料とは異なったうま味を生ずることを熟成という。イカ、カツオなどの塩辛は米麹(こめこうじ)を加えるとうま味を増すが、これは麹の出す酵素が塩辛の熟成を助けるとともに、米デンプンに麹の産生したアミラーゼが働き、麦芽糖やブドウ糖を生じ甘味を増すためである。なお、塩辛の熟成には、繁殖した細菌や酵母などの微生物が出す酵素も関与するといわれる。この際、食塩濃度により繁殖する微生物の種類や数が異なるが、食塩量が10％程度のときは、当然20％添加に比べ微生物の種類や数は多くなる。そのため早く熟成する。一方、20％もの食塩を加えると微生物は繁殖しにくくなり、熟成への寄与も減る。最近、消費者は高血圧への恐れから食塩のとりすぎを嫌うため、塩辛に加える食塩も減り、食塩だけでは腐敗を抑えられず、冷蔵庫に貯蔵する必要がある。

　栄養面では、動物性タンパク質がいくぶん消化された形のため消化されやすく、栄養価は高いが、食塩を10％も含むので食塩のとりすぎになるのが欠点である。

　生産はイカの塩辛（白作り、赤作り、黒作りなど）がもっとも多く3000トン程度、ウニ塩辛が1500トンでこれに次ぐ。その他のものは全部あわせても2000トンぐらいで、地方の名産品になっているものが多い。酒の肴(さかな)や飯の菜とされるが、生産は停滞している。

［金田尚志］

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