View source for Kombu

{{Short description|Edible kelp}}
{{other uses}}
[[File:Kombu.jpg|thumb|Dried kombu]]
[[File:Dried kombu in a supermarket.jpg|thumb|Dried kombu sold in a Japanese supermarket]]

'''''Kombu''''' or '''''Konbu''''' (from {{langx|ja|[[wikt:昆布|昆布]]|konbu or kombu}}) is edible [[kelp]] mostly from the family [[Laminariaceae]] and is widely eaten in [[East Asia]].<ref name=Abbott>{{cite book|last=Abbott|first=Isabella A|author-link=Isabella Abbott|chapter=Food and food products from seaweeds|editor1-last=Lembi|editor1-first=Carole A.|editor2-last=Waaland|editor2-first=J. Robert|title=Algae and human affairs|year=1989|page=141|publisher=[[Cambridge University Press]], [[Phycological Society of America]]|isbn=978-0-521-32115-0}}</ref> It may also be referred to as '''''dasima''''' ({{langx|ko|다시마}}) or '''''haidai''''' ({{zh|t=[[wikt:海帶|海帶]]|s=[[wikt:海带|海带]]|p=Hǎidài}}).

Kelp features in the diets of many civilizations, including Chinese and Icelandic; however, the largest consumers of kelp are the Japanese, who have incorporated kelp and seaweed into their diets for over 1,500 years.<ref>{{cite web|last1=Wurges|first1=Jennifer|last2=Frey|first2=Rebecca|title=Kelp|url=http://www.encyclopedia.com/topic/kelp.aspx|website=Gale Encyclopedia of Alternative Medicine|publisher=The Gale Group, Inc|access-date=31 July 2015}}</ref>

== Prominent species ==
There are about eighteen edible species in Laminariaceae and most of them, but not all, are called kombu. Confusingly, species of Laminariaceae have multiple names in [[biology]] and in [[fisheries science]]. In the following list, fisheries science synonyms are in parentheses, and Japanese names follow them.{{cn|date=October 2023}}
* ''[[Saccharina japonica]]'' (''Laminaria japonica''), {{Interlanguage link multi|Ma-kombu|ja|3=コンブ}}
** ''Saccharina japonica'' var. ''religiosa'' (''Laminaria religiosa''), {{Interlanguage link multi|Hosome-kombu|ja|3=コンブ}}
** ''Saccharina japonica'' var. ''diabolica'' (''Laminaria diabolica''), {{Interlanguage link multi|Oni-kombu|ja|3=コンブ}} l
** ''Saccharina japonica'' var. ''ochotensis'' (''Laminaria ochotensis''), {{Interlanguage link multi|Rishiri-kombu|ja|3=コンブ}} – commonly used for soup stocks
* ''[[Saccharina latissima]]'' (''Laminaria saccharina''), Karafuto-kombu – contains [[mannitol]] and is considered sweeter
* ''[[Saccharina angustata]]'' (''Laminaria angustata''), {{Interlanguage link multi|Mitsuishi-kombu|ja|3=コンブ}} – commonly used in the making of [[dashi]]
* ''[[Saccharina longissima]]'' (''Laminaria longissima''),　{{Interlanguage link multi|Naga-kombu|ja|3=コンブ}}
* ''[[Saccharina coriacea]]'' (''Laminaria coriacea''), {{Interlanguage link multi|Gaggara-kombu|ja|3=コンブ}}
* ''[[Saccharina sculpera]]'' (''Kjellmaniella sculpera''), {{Interlanguage link multi|Gagome-kombu|ja|3=ガゴメコンブ}}
* ''[[Saccharina longipedalis]]'' (''Laminaria longipedalis''), Enaga-kombu
* ''[[Saccharina gyrata]]'' (''Kjellmaniella gyrata''), {{Interlanguage link multi|tororo-kombu|ja|3=トロロコンブ}}
* ''[[Saccharina cichorioides]]'' (''Laminaria cichorioides''), Chijimi-kombu
* ''[[Arthrothamnus bifidus]]'', {{Interlanguage link multi|nekoashi-kombu|ja|3=コンブ}}

== Etymology ==
Kombu is a [[loanword]] from [[Japanese language|Japanese]].

In Old Japanese, edible seaweed was generically called "''me''" (cf. [[wakame]], [[arame]]) and [[kanji]] such as "軍布",<ref>[[Man'yōshū]] and wood strips from [[Fujiwara-kyō]]. Between late 7th and early 8th century</ref> 海藻<ref>{{Interlanguage link multi|Shōsōin Monjo|ja|3=正倉院文書}}　(documents of [[Shōsōin]]; 8th century) and [[Fudoki]].</ref> or "和布"<ref>色葉字類抄 ([[Iroha Jiruishō]]; the vocabulary of Japanese and Chinese. Middle or late 12th century.</ref> were applied to transcribe the word. Especially, kombu was called [[wikt:広布|''hirome'']] (from ''hiroi'', wide) or [[wikt:えびすめ|''ebisume'']] (from [[Emishi|''ebisu'']]).<ref>本草和名 ({{Interlanguage link multi|Honzō Wamyō|ja|3=本草和名}}); the oldest surviving dictionary of medicine in Japan. Early 10th century.</ref>  Sometime later the names ''konfu'' and ''kofu'' appeared respectively in two editions of Iroha Jiruishō in 12th–13th century.<ref>The latter is revised and enlarged edition 伊呂波字類抄 (Iroha Jiruishō). 13th century.</ref>

Various theories have been claimed for the origin of the name kombu, with the following two predominant today.{{cn|date=October 2023}}

One is that it originated from the [[Kanji#On'yomi (Chinese reading)|on'yomi]] ([[Kanji|Sino-Japanese]] reading) of the Chinese name 昆布 (kūnbù).<ref>谷川士清 ([[Tanikawa Kotosuga]]) et al., 和訓栞 (Wakun no Shiori). 1777–1899.</ref> The kanji itself already could be seen in ''Shōsōin Monjo'' (8th century) and ''[[Shoku Nihongi]]'' (797) in Japan, and furthermore trace back in China, as early as 3rd century, to the book ''Wupu Bencao'' (around 239).<ref>吳普本草 (Wupu Bencao) is the Chinese materia medica work written by　Wupu.</ref> [[Li Shizhen]] wrote the following in his ''[[Bencao Gangmu]]'' (1596):

{{quotation|Come to think about it, Wupu Bencao says "綸布 (gūanbù), alias 昆布 (kūnbù)." Then, what is mentioned in the [[Erya]] as "(what is pronounced) 綸 resembles 綸.  This is in the [[East China Sea]]" kūnbù.  The pronunciation of 綸 is 関 (gūan), meaning cord made by green thread, and got corrupted to 昆 (kūn).|Li Shizhen, ''Bencao Gangmu''<ref name="Li">{{Cite web|url=https://zh.wikisource.org/wiki/%E6%9C%AC%E8%8D%89%E7%B6%B1%E7%9B%AE/%E8%8D%89%E4%B9%8B%E5%85%AB|title=本草綱目/草之八 – 维基文库，自由的图书馆|website=zh.wikisource.org}}</ref>}}

Another possibility to explain the association arises because descriptions of kūnbù in Chinese documents are vague and inconsistent, and it is impossible to identify to which seaweed the term might have applied.  For instance, Chen Cangqi (681–757) noted: "kūnbù is produced in the [[South China Sea]]; its leaf is like a hand and the size is the same as a [[Miscanthus sinensis|silver grass]] and a [[Reed (plant)|reed]], is of red purple; the thin part of leaf is seaweed",<ref name="Li" /> which is similar to wakame, arame, kurome, or kajime (''[[Ecklonia cava]]''). The difficulty is that, at least in that time, kombu was not produced either in the East nor in the South China Sea.  Moreover, following Zhang Yxi, Li Shizhen classified kūnbù and haidai (stands for kombu in Chinese) as different things,<ref name="Li" /> and this classification continues in China today.<ref>Wang Cheyueh 王者悅 (ed.), 中国药膳大辞典 (Chinese Medicated Diet Dictionary), Dalian, Dalian Publishing House, 1992.</ref>

== History ==
Although archaeological evidence of seaweed is hard to find because of its easy decomposition, some plant remains of wakame seaweed are found in some ruins of the [[Jōmon Period]]<ref>{{Cite web|url=http://www.hijiki.org/html/content02.htm|title=日本ひじき協議会|website=www.hijiki.org}}</ref> which leads to the supposition that kombu was also eaten at that time. As to surviving documents, the letters 軍布 (in Sino-Japanese reading 軍 is gun/kun; 布 is fu/pu/bu) appeared in Man'yōshū and wood strips from Fujiwara-kyō, and may have indicated kombu. The ''Shoku Nihongi'' (797) reports: in 797 {{Interlanguage link multi|Suga no Komahiru|ja|3=須賀古麻比留}} of [[Emishi]] (Ainu or Tohoku region people) stated they had been offering up kombu, which grew there, as tribute to the [[Yamato period#The Yamato state|Yamato court]] every year without fail. The [[Engishiki]] (927) also reports that kombu had been offered up by [[Mutsu Province|Mutsu]].{{cn|date=October 2023}}

During the [[Muromachi period]], a newly developed drying technique allowed kombu to be stored for more than a few days, and it became an important export from the Tohoku area.{{Citation needed|date=March 2008}} By the [[Edo period]], as Hokkaidō was colonized and shipment routes were organized, the use of ''kombu'' became widespread throughout Japan. Traditional [[Okinawan cuisine]] relies heavily on ''kombu'' as a part of the diet; this practice began in the Edo period. Okinawa uses more ''kombu'' per household than any other prefecture. In the 20th century, a way to cultivate kombu was discovered and it became cheap and readily available.<ref>{{cite journal |last1= Drew |first1= Kathleen M. |year=1949 |title= Conchocelis-phase in the life-history of Porphyra umbilicalis (L.) Kütz|journal=Nature |volume= 164|issue= 4174|pages= 748–749|doi= 10.1038/164748a0|bibcode= 1949Natur.164..748D |s2cid= 4134419 }}</ref>

In 1867, the word "kombu" first appeared in an English-language publication—''A Japanese and English Dictionary'' by [[James Curtis Hepburn]].

[[Umami]], a [[basic taste]], was first scientifically identified in 1908 by [[Kikunae Ikeda]] through his experimentation with ''kombu''.<ref name="Ikeda_2002">{{cite journal | vauthors = Ikeda K | title = New seasonings | journal = Chemical Senses | volume = 27 | issue = 9 | pages = 847–849 | date = November 2002 | pmid = 12438213 | doi = 10.1093/chemse/27.9.847 | doi-access = free }} (Partial translation of {{cite journal | vauthors = Ikeda K | title=New Seasonings | language = Japanese  | journal = Journal of the Chemical Society of Tokyo | year= 1909 | volume=30 | pages= 820–836}})</ref><ref>{{cite journal | vauthors = Nakamura E | title = One hundred years since the discovery of the 'umami' taste from seaweed broth by Kikunae Ikeda, who transcended his time | journal = Chemistry: An Asian Journal | volume = 6 | issue = 7 | pages = 1659–1663 | date = July 2011 | pmid = 21472994 | doi = 10.1002/asia.201000899 }}</ref> He found that [[glutamic acid]] was responsible for the palatability of the ''dashi'' broth created from ''kombu'', and was a distinct sensation from sweet, sour, bitter, and salty tastes.<ref name="Kean_2015">{{cite journal| vauthors = Kean S |title=The science of satisfaction|journal=[[Distillations Magazine]]|date=Fall 2015 |volume=1|issue=3|pages=5|url=https://www.sciencehistory.org/distillations/magazine/the-science-of-satisfaction|access-date=22 March 2018}}</ref> Ikeda named the newly-discovered taste ''umami'' (うま味), from the Japanese word ''umai'' (うまい, "delicious").<ref>{{cite web|url=http://umamibook.net/what-is-umami|title=What is umami?|publisher=[[Columbia University Press]]|access-date=5 June 2017}}</ref>

Since the 1960s, dried ''kombu'' has been exported from Japan to many countries. It was available initially at Asian, and especially Japanese, food shops and restaurants, and can be found in supermarkets, health-food stores, and other nonspecializing suppliers.{{cn|date=October 2023}}

== Cooking ==

=== Japan ===
Kombu is sold dried (''dashi konbu'') or pickled in vinegar (''su konbu'') or as a dried shred (''oboro konbu'', ''tororo konbu'' or ''shiraga konbu''). It may also be eaten fresh in ''[[sashimi]]''.

Kombu is used extensively in [[Japanese cuisine]]s as one of the three main ingredients needed to make ''[[dashi]]'', a soup stock. ''Konbu dashi'' is made by putting either whole dried or powdered kombu in cold water and heating it to near-boiling. The softened kombu is commonly eaten after cooking or is sliced and used to make ''[[tsukudani]]'', a dish that is simmered in soy sauce and ''[[mirin]]''.

Kombu may be pickled with sweet-and-sour flavoring, cut into small strips about 5 or 6&nbsp;cm long and 2&nbsp;cm wide. These are often eaten as a snack with [[green tea]]. It is often included when cooking beans, putatively to add nutrients and improve their digestibility.

''[[Konbu-cha]]'' or ''kobu-cha'' ({{lang|ja-Hani|昆布茶}}) is a tea made by infusing kombu in hot water.  What Americans call [[kombucha]] is called "kōcha kinoko" in Japan.<ref>{{cite news |last=Wong |first=Crystal |url=http://www.japantimes.co.jp/news/2007/07/12/national/u-s-kombucha-smelly-and-no-kelp/ |title=U.S. 'kombucha': Smelly and No Kelp |work=Japan Times |date=12 July 2007 |access-date=14 June 2015}}</ref>

Kombu is also used to prepare a seasoning for rice to be made into [[sushi]].

<gallery>
Tsukudaniphoto.jpg|A dish of ''[[tsukudani]]'' made from kombu
Oden,_Japanese_food_for_winter.jpg|Kombu in ''[[Oden]]''
Kobumaki,_Kombumaki,_Kombu_roll.jpg|''[[Kobumaki]]'' (kombu roll). Usually fish like [[herring]] is inside.
Nimono_with_kombu.jpg|''[[Nimono]]'' with kombu
</gallery>

== Nutrition and health effects ==
''Kombu'' is a good source of [[glutamic acid]], an amino acid responsible for [[umami]] (the Japanese word used for a [[Basic tastes|basic taste]] identified in 1908). Several foodstuffs in addition to ''kombu'' provide glutamic acid or [[glutamate]]s.

''Kombu'' contains extremely high levels of [[iodine]]. While this element is essential for normal growth and development, the levels in kombu can cause overdoses; it has been blamed for thyroid problems after drinking large amounts of soy milk in which ''kombu'' was an additive.<ref name="RACGP">{{cite web|url=http://www.racgp.org.au/healthalerts/35472 |title=RACGP Health alert – high levels of iodine in BonSoy soy milk |date=24 December 2009 |publisher=Royal Australian College of General Practitioners |access-date=3 November 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100818205757/http://www.racgp.org.au/healthalerts/35472 |archive-date=August 18, 2010 }}</ref>

It is also a source of [[dietary fiber]].  Algae including kombu also contain entire families of obscure enzymes that break down complex sugars that are normally indigestible to the human gut (thus gas-causing).<ref>{{cite journal | doi=10.1016/j.sbi.2014.07.009 | volume=28 | title=A sweet new wave: structures and mechanisms of enzymes that digest polysaccharides from marine algae | journal=Current Opinion in Structural Biology | pages=77–86 | pmid=25136767 | last1 = Hehemann | first1 = JH | last2 = Boraston | first2 = AB | last3 = Czjzek | first3 = M| year=2014 }}</ref> It also contains the well-studied [[alpha-galactosidase]] and [[beta-galactosidase]] enzymes.<ref>{{cite journal | doi=10.1134/S0026261712060033 | volume=81 | issue=6 | title=Diversity of glycosidase activities in the bacteria of the phylum Bacteroidetes isolated from marine algae | journal=Microbiology | pages=688–695| year=2012 | last1=Bakunina | first1=I. Yu | last2=Nedashkovskaya | first2=O. I | last3=Kim | first3=S. B | last4=Zvyagintseva | first4=T. N | last5=Mikhailov | first5=V. V | s2cid=14531224 }}</ref>

== Biofuel ==

Genetically manipulated ''[[Escherichia coli|E. coli]]'' bacteria can digest ''kombu'' into [[ethanol]], making it a possible maritime [[biofuel]] source.<ref>[http://www.scientificamerican.com/article.cfm?id=genetically-engineered-stomach-microbe-turns-seaweed-into-ethanol Genetically Engineered Stomach Microbe Converts Seaweed into Ethanol], [[Scientific American]], 2012-01-19</ref><ref>[https://www.science.org/doi/10.1126/science.1214547 An Engineered Microbial Platform for Direct Biofuel Production from Brown Macroalgae], [[Science (magazine)|Science]], 2012-01-20</ref>

==See also==
* {{annotated link|Kelp}}
* {{annotated link|Laverbread}}

==Notes==
{{reflist}}

==References==
{{refbegin}}
* Davidson, Alan. Oxford Companion to Food (1999), "Kombu", p.&nbsp;435 {{ISBN|0-19-211579-0}}
* [http://www.fao.org/docrep/field/003/AB724E/AB724E00.htm Culture of Kelp (Laminaria japonica) in China]
* {{cite book|title=A dictionary of Japanese food: ingredients & culture|first=Richard |last=Hosking|url=https://books.google.com/books?id=NN-U5BJJhUMC&q=kombu&pg=PA207|year=1996|publisher=Tuttle Publishing|isbn=978-0-8048-2042-4|pages=206–208}}
{{refend}}

==External links==
{{Commons category|Kombu}}
{{Wiktionary}}
* [http://www.kurakonusa.com/kombu/encyclopedia/index.html Kombu seaweed encyclopedia] {{Webarchive|url=https://web.archive.org/web/20161022012441/http://www.kurakonusa.com/kombu/encyclopedia/index.html |date=2016-10-22 }}

{{Japanese food and drink}}
{{portal bar|Food}}

[[Category:Plant common names]]
[[Category:Japanese condiments]]
[[Category:Japanese cuisine terms]]
[[Category:Laminariaceae]]
[[Category:Edible seaweeds]]
[[Category:Umami enhancers]]