Umami Information by Food

Umami Information by Food Kombu (Kelp)

Kombu belongs to the brown-algae family, harvested on the coasts of Hokkaido, the northern island of the archipelago and in Tohoku, the north-eastern part of the main island of Honshu. There are various species of algae. Among them, those most commonly used for dashi (Japanese stock) are makombu, rishiri-kombu, rausu-kombu. Hidaka-kombu is simmered with seasonings to be used as side dishes such as simmered kombu and takiawase. Kombu for dashi is grown for two years and harvested from July through September. Kombu is abundant in the umami substance glutamate.

  • Kombu (Kelp)

    ©Umami Information Center

  • Kombu (Kelp)

    ©Umami Information Center

Japan Kombu Map

Levels of naturally occurring glutamate(mg/100g):

Levels of naturally occurring glutamate(mg/100g)

Main Amino Acids in Various Konbu Dash(Konbu left in water for 15 minutes)

Main Amino Acids in Various Konbu Dash(Konbu left in water for 15 minutes)

Dashi

The choicest knob (kelp) used to be shipping with great care from far off Hokkaido to Kyoto, the ancient capital of Japn that flourished for nearly a thousand years. In the Heian period (794-1185), shogun ryori, a type of vegetarian cooking, was introduced from along with the teaching of Buddhism warning against the taking of life. The ingredients used in shogun ryori consist entirely of vegetables and soybean products--meat, fish or seafood are never used. Konbu dash (kelp stock) is indispensable for enhancing the taste of the vegetables used in shogun ryori. The Dashi used in Japanese cuisine is very easy to make. Have you ever tasted a knob dash in its purest from? If you haven’t, cut a piece of kelp and put it in a cup, and add water. Let it sit for about 20 minutes. Dashi will begin oozing out from the kelp in a few minutes. Try it. A light, subtle taste will fill your mouth. What makes the dash so indescribably delicious is the umami. The main ingredients of umami are glutamin acid and aspartic acid. Both are amino acids.

Kombu (Kelp)だし

Ichiban dash (1st brewed) is made by adding lots of katsuobushi (dried bonito) to knob dash when it comes to a boil. Ichiban dash is then strained with a strainer covered with thin cloth on top. Although katsuobushi is added to knob dash for only a few seconds, the umami taste of ichiban dash is more pronounced than that of knob dash. The fragrance of katsuobushi then increases. Inosinic acid is a key ingredient in the umami taste of katsuobushi. Moreover the umami taste of dash is greatly enhanced when the glutamic acid found in knob meets the inosinic acid of katsuobushi.Adding katsuobushi to knob certainly has a wonderful synergic effect.

一番だし

The power of kombu Fluke Kobu-Jime

With its chewy yet delicate translucent flesh and a clean, subtle taste thanks to its low fat content, the fluke* is one of the best loved of high-quality fish. In order to best enhance these natural features, the fluke, when cooked as part of Japanese cuisine, is often treated to a preparation known as Kobu-Jime, or placing the fish between sheets of kombu. Kobu-Jime is an extremely simple technique, but is credited with increasing the perceptible umami of the fish flesh to a great extent, giving the resulting sashimi a superb taste.
*The fluke is also known variously as flatfish,flounder,and halibut.

【 Kobu-Jime fluke sashimi-method 】

  • 1. Fillet the fluke, cutting either four fillets (upper and lower tail and head end) only or six, by also cutting two smaller engawa, or porch, fillets from around the fins on both sides.

  • 2. Wipe the dust and impurities off the dried kombu with a moist cloth.

  • 3. Place each fillet of fluke between two pieces of kombu, one on top and one underneath.

  • 4. Tightly wrap each fillet in cling film and leave to refrigerate overnight.

  • 5. Cut the fillet into fine sashimi pieces.

*If you are using pre-cut fluke sashimi, wrap each slice in cling film between two pieces of kombu and refrigerate for 2-3 hours.

The power of kombu Fluke Kobu-Jime

It certainly tastes like the amount of umami in a fluke prepared by Kobu-Jime is far greater than that of an untreated fish. We should still ask whether there is actually an observable difference in the level of umami present in treated and untreated fish.
Results of the analysis showed that 100g of untreated fluke sashimi contains 12 mg of glutamate. Compare this with 100g of fluke sashimi treated with Kobu-Jime, which contains 320mg of glutamate. The Kobu-Jime treated fluke also contains greater levels of asparagine, the amino acid contained in kombu. On the other hand, no discrepancy was seen between the levels of inosinate found in the two kinds of fluke, the nucleotide which contributes to giving a food umami. The difference in the levels of glutamate found in the two kinds of fluke sashimi can be explained when we consider that 100g of kombu (makombu) is known to contain 3000mg (3g) of glutamate. When the fluke is placed between sheets of kombu during Kobu-Jime, this glutamate is then able to thoroughly infiltrate the flesh of the fish. This is the truly marvellous power of kombu.

Comparison of treated and untreated fluke sashimi

Comparison of treated and untreated fluke sashimi