is
simmered,
smoked and
fermented skipjack tuna
The skipjack tuna (''Katsuwonus pelamis'') is a medium-sized perciform fish in the tuna family, Scombridae. It is otherwise known as the balaya (Sri Lanka), bakulan/kayu (North Borneo), tongkol/aya (Malay Peninsula/Indonesia), aku (Hawaii), caka ...
(''Katsuwonus pelamis'', sometimes referred to as
bonito
Bonitos are a tribe of medium-sized, ray-finned predatory fish in the family Scombridae – a family it shares with the mackerel, tuna, and Spanish mackerel tribes, and also the butterfly kingfish. Also called the tribe Sardini, it consists ...
). It is also known as bonito flakes. ''Katsuobushi'' or similarly prepared fish is also known as .
Shaved ''katsuobushi'' and dried
kelp—''
kombu''—are the main ingredients of ''
dashi'', a broth that forms the basis of many soups (such as
miso
is a traditional Japanese seasoning. It is a thick paste produced by fermenting soybeans with salt and ''kōji'' (the fungus '' Aspergillus oryzae'') and sometimes rice, barley, seaweed, or other ingredients. It is used for sauces and ...
) and sauces (e.g., ''
soba
Soba ( or , "buckwheat") is a thin Japanese noodle made from buckwheat. The noodles are served either chilled with a dipping sauce, or hot in a noodle soup. The variety ''Nagano soba'' includes wheat flour.
In Japan, soba noodles can be found ...
no tsukejiru'') in
Japanese cuisine
Japanese cuisine encompasses the regional and traditional foods of Japan, which have developed through centuries of political, economic, and social changes. The traditional cuisine of Japan ( Japanese: ) is based on rice with miso soup and oth ...
.
''Katsuobushi''s distinct
umami taste comes from its high
inosinic acid
Inosinic acid or inosine monophosphate (IMP) is a nucleotide (that is, a nucleoside monophosphate). Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in ...
content. Traditionally made ''katsuobushi'', known as ''karebushi'', is deliberately fermented with ''
Aspergillus glaucus'' fungus in order to reduce moisture. ''Katsuobushi'' has also been shown to impart "
kokumi
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...
" (i.e. enhances flavor).
Traditional production process
The fish is beheaded, gutted, and
filleted, with the fatty belly, which does not lend well to being preserved, trimmed off. The fillets are then arranged in a basket and simmered just below boiling for an hour to an hour and a half, depending on their size.
The rib bones are then removed and the fillets smoked for up to a month using
oak,
pasania, or
castanopsis wood. They are smoked for 5-6 hours in one session, left to rest one day for the condensation to rise to the surface, then fired and smoked again the next day. This smoking and resting cycle is repeated 12–15 times in total. The built-up tar from the smoke is cleaned from the surface using a grinder. At this stage the fillets are called ' and most commonly found in stores shaved and packaged for sale under the name ' or ''hanakatsuo''. They are not true ''katsuobushi'' without the last fermentation stage, but still valued as a good substitute.
The last stage of creating ''katsuobushi'' is to allow the fish to
sun-dry using the assistance of mold. The fillets are sprayed with ''
Aspergillus glaucus'' culture and left for two weeks in a closed cultivation room. The mold ferments the fillets and also draws out any residual moisture.
The mold is continually scraped off, with further sun-drying increasing hardness and dryness until the fillet resembles a piece of wood, with less than 20% of its original weight. By definition, only fillets that have been treated in this manner may be referred to as ''katsuobushi''. However, after repeating this process of mold growth and sun-drying at least twice, the ''katsuobushi'' can also be called , and fillets repeating this process more than three times can be called . When tapped together lightly, they sound almost metallic, and unlike their dull beige outer appearance, when broken open they are a translucent deep ruby color inside. Rarely, very high-end ''honkarebushi'' repeat this drying process for over two years.
In the Edo era, it was common for ''katsuobushi'' to go through an extra step, the so-called process. After the fillets are boiled and their rib bones removed the fish are put in steaming baskets stacked atop one another for one to two hours a few meters above a burning wood fire. These are rotated to assure an equal exposure to the smoke. The result is more flavorful and resistant to deterioration. Due to the extra cost and facilities required only a few factories following ''tebiyama-shiki'' remain.
Shaving
Traditionally, chunks of ''katsuobushi'' were shaved as needed with an instrument similar to a
wood plane called a ''
katsuobushi kezuriki''.
Today ''katsuobushi'' is typically sold in bags of small pink-brown shavings, which vary by thickness: smaller, thinner shavings, called ''hanakatsuo'' (), are used as a flavoring and topping for many Japanese dishes, such as
okonomiyaki, while the larger thicker, called ''kezurikatsuo'' (), are favored for making the widely used dashi stock.
Uses
In addition to making dashi, other popular uses of ''katsuobushi'' include:
* Okaka, finely chopped ''katsuobushi'' dressed with soy sauce.
** As a stuffing for rice balls (''
onigiri'').
** As a topping for rice. Popular for
bentō, often covered with
strips of laver.
** Dried okaka is used as an ingredient of ''
furikake'' rice topping (called "okaka furikake").
* As a seasoning for cold
tofu (''
hiyayakko
is a Japanese dish made with chilled tofu and toppings.
Variety of toppings
The choice of toppings on the tofu vary among households and restaurants, but a standard combination is chopped green onion with katsuobushi (dried skipjack tuna fl ...
'', ) along with grated
ginger
Ginger (''Zingiber officinale'') is a flowering plant whose rhizome, ginger root or ginger, is widely used as a spice and a folk medicine. It is a herbaceous perennial which grows annual pseudostems (false stems made of the rolled bases of ...
and
Welsh onion (a type of
spring onion).
* Sprinkled with
sesame
Sesame ( or ; ''Sesamum indicum'') is a flowering plant in the genus ''Sesamum'', also called benne. Numerous wild relatives occur in Africa and a smaller number in India. It is widely naturalized in tropical regions around the world and is cul ...
seeds and chopped
laver atop cold soba noodles (
zarusoba).
* As a topping on
takoyaki
is a ball-shaped Japanese snack made of a wheat flour-based batter and cooked in a special molded pan. It is typically filled with minced or diced octopus (''tako''), tempura scraps (''tenkasu''), pickled ginger (''beni shoga''), and green o ...
and
okonomiyaki.
* As a seasoning on
preserved egg along with
sesame oil and
soy sauce.
* As a high-protein treat for
cats sold at pet stores.
* As a topping for ramen mixed with salt.
Health
The
mycotoxin beta-nitropropionic acid has been found on ''katsuobushi'' as well as in
miso
is a traditional Japanese seasoning. It is a thick paste produced by fermenting soybeans with salt and ''kōji'' (the fungus '' Aspergillus oryzae'') and sometimes rice, barley, seaweed, or other ingredients. It is used for sauces and ...
and in
soy sauce, two other Japanese fungal fermented products. Certain strains of ''A. glaucus'' are reported to produce mycotoxins.
Due to the smoking process which involves tar and charcoal, amounts of
benzopyrene
A benzopyrene is an organic compound with the formula C20H12. Structurally speaking, the colorless isomers of benzopyrene are pentacyclic hydrocarbons and are fusion products of pyrene and a phenylene group. Two isomeric species of benzopyrene ar ...
exceeding EU standards, as much as 37μg per kilogram, have been detected in commercially sold ''katsuobushi''. As a result, they have been once banned for sale in the European Union.
See also
*
List of dried foods
*
Maldive fish
References
External links
Katsuobushi types and production methods*
{{Authority control
Japanese condiments
Dried fish
Fermented fish
Smoked fish
Umami enhancers
Toppings