Wasabi

Summary

Wasabi (Japanese: ワサビ, わさび, or 山葵, pronounced [waꜜsabi]) or Japanese horseradish ( Eutrema japonicum[3] syn. Wasabia japonica)[4] is a plant of the family Brassicaceae, which also includes horseradish and mustard in other genera. The plant is native to Japan and the Russian Far East[1] including Sakhalin, as well as the Korean Peninsula.[5]: 133  It grows naturally along stream beds in mountain river valleys in Japan.

Wasabi
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Brassicales
Family: Brassicaceae
Genus: Eutrema
Species:
E. japonicum
Binomial name
Eutrema japonicum
Synonyms[3]
  • Wasabia japonica (Miq.) Matsum.
  • Alliaria wasabi (Maxim.) Prantl
  • Cochlearia wasabi Siebold.
  • Eutrema koreanum
  • Eutrema okinosimense Taken.
  • Eutrema wasabi Maxim
  • Lunaria japonica (basionym) Miq.[2]
  • Wasabia hederifolia
  • Wasabia okinosimensis (Taken.) Hatus.
  • Wasabia pungens Matsum.
  • Wasabia wasabi (Maxim.) Makino

It is grown for its rhizomes which are ground into a paste as a pungent condiment for sushi and other foods. It is similar in taste to hot mustard or horseradish rather than chilli peppers in that it stimulates the nose more than the tongue, but freshly grated wasabi has a subtly distinct flavour.[6]: 53  The two main cultivars in the marketplace are E. japonicum 'Daruma' and 'Mazuma', but there are many others.[6]

The oldest record of wasabi as a food dates to the 8th century AD.[7] The popularity of wasabi in English-speaking countries has coincided with that of sushi, growing steadily starting in about 1980.[8] Due to constraints that limit the Japanese wasabi plant's mass cultivation and thus increase its price and decrease availability outside Japan, the western horseradish plant is widely used in place of the Japanese wasabi. This version is commonly referred to as "western wasabi" (西洋わさび) in Japan.

Taxonomy edit

Siebold named Cochlearia (?) wasabi in 1830, noting its use pro condimento or "as a condiment";[9]: 54  however, this is a nomen nudum, and the synonym Eutrema wasabi, published by Maximovich in 1873,[10]: 283  is thus an illegitimate name.[5]: 133  The wasabi plant was first described by Miquel in 1866, as Lunaria (?) japonica, from the type collected by Siebold in Japan, though the precise type locality was not recorded.[2]: 74 

In 1899 Matsumura erected the genus Wasabia, recognising within it the species Wasabia pungens and Wasabia hederaefolia;[11] these are now regarded as synonyms of Eutrema japonicum.[5]: 133  In 1912 Matsumura recognised the species Wasabia japonica, treating his earlier Wasabia pungens as a synonym.[12] In 1930, Koidzumi transferred the wasabi plant to the genus Eutrema,[13] the correct name and author citation being Eutrema japonicum (Miq.) Koidz.[1]

Description edit

It has large leaves produced from long, thin stalks.[6]: 54  They are simple and large, 3–6 inches (7.6–15.2 cm) long and 3–6 inches (7.6–15.2 cm) wide with palmate veins.[14]

Wasabi flowers appear in clusters from long stems that bloom from late winter to early spring.[14][additional citation(s) needed]

Uses edit

 
Wasabi root and wasabi paste on a plate

Wasabi is generally sold either as a rhizome[15] or stem, which must be grated very fine before use, as a dried powder, or as a ready-to-use paste in tubes similar to toothpaste tubes.[16]

The part used for wasabi paste is variously characterised as a rhizome,[17][18] a stem,[19][20] or the "rhizome plus the base part of the stem".[21]

In some high-end restaurants the paste is prepared when the customer orders and is made using a grater to grate the stem; once the paste is prepared, it loses flavour in 15 minutes if left uncovered.[22] In sushi preparation chefs usually put the wasabi between the fish and the rice because covering wasabi until served preserves its flavour.

Fresh wasabi leaves can be eaten raw, having the spicy flavor of wasabi stems, but a common side effect is diarrhea.[citation needed]

Legumes (peanuts, soybeans, or peas) may be roasted or fried and then coated with wasabi powder mixed with sugar, salt, or oil and eaten as a crunchy snack. In Japan, it is called wasabi-mame (わさび豆, "wasabi bean").

Surrogates edit

 
Wasabi crop growing at Azumino, Nagano, Japan

Wasabi favors growing conditions that restrict its wide cultivation – among other things, it is quite intolerant of direct sunlight, requires an air temperature between 8 and 20 °C (46 and 68 °F), and prefers high humidity in summer. This makes fully satisfying commercial demand impossible for growers, which makes wasabi quite expensive.[23][24][25] Therefore, outside Japan, finding real wasabi plants is rare.

A common substitute is a mixture of horseradish, mustard, starch, and green food colouring or spinach powder.[26] Often packages are labelled as wasabi while the ingredients do not include any part of the wasabi plant. The primary difference is colour, with wasabi being naturally green.[27] Fresh horseradish root is described as having a similar (albeit simpler) flavor and texture to that of fresh wasabi.[28]

In Japan, horseradish is referred to as seiyō wasabi (西洋わさび, "western wasabi").[29] Outside of Japan, where fresh wasabi is hard to obtain, a powdered mixture of horseradish and mustard oil, known as kona wasabi, is used at a majority of sushi restaurants, including reputable ones.[30] In the United States, true wasabi is generally found only at specialty grocers and high-end restaurants.[31]

Chemistry edit

The chemical in wasabi that provides its initial pungency is the volatile compound allyl isothiocyanate, which is produced by hydrolysis of allyl glucosinolate, a natural thioglucoside (conjugates of the sugar glucose and sulfur-containing organic compounds); the hydrolysis reaction is catalyzed by myrosinase and occurs when the enzyme is released on cell rupture caused by maceration – e.g., grating – of the plant.[32][33][34] The same compound is responsible for the pungency of horseradish and mustard. Allyl isothiocyanate can also be released when the wasabi plants have been damaged because it is being used as a defense mechanism.[35] The sensory neural target of mustard oil is the chemosensory receptor, TRPA1, also known as the wasabi receptor.[36]

The unique flavour of wasabi is a result of complex chemical mixtures from the broken cells of the plant, including those resulting from the hydrolysis of thioglucosides, including sinigrin[37] and other glucosinolates, into glucose and methylthioalkyl isothiocyanates:[22][32][33]

  • 6-(Methylsulfinyl)hexyl isothiocyanate (6-MITC)
  • 7-Methylthioheptyl isothiocyanate
  • 8-Methylthiooctyl isothiocyanate

Such isothiocyanates inhibit microbial growth, perhaps with implications for preserving food against spoilage and suppressing oral bacterial growth.[38]

Because the burning sensations of wasabi are not oil-based, they are short-lived compared to the effects of capsaicin in chilli peppers and are washed away with more food or liquid. The sensation is felt primarily in the nasal passage and can be painful depending on the amount consumed. Inhaling or sniffing wasabi vapor has an effect like smelling salts, a property exploited by researchers attempting to create a smoke alarm for the deaf. One deaf subject participating in a test of the prototype awoke within 10 seconds of wasabi vapour sprayed into his sleeping chamber.[39] The 2011 Ig Nobel Prize in Chemistry was awarded to the researchers for determining the ideal density of airborne wasabi to wake people in the event of an emergency.[40]

Nutritional information edit

 
Fresh wasabi stems

Wasabi is normally consumed in such small quantities that its nutritional value is negligible. The major constituents of raw wasabi root are carbohydrates (23.5%), water (69.1%), fat (0.63%), and protein (4.8%).[41]

Cultivation edit

 
A drawing of a wasabi plant, published in 1828 by Iwasaki Kanen
 
Plastic bottle of prepared wasabi sauce in the U.S.

Few places are suitable for large-scale wasabi cultivation, which is difficult even in ideal conditions. In Japan, wasabi is cultivated mainly in these regions:

2016 wasabi production in Japan (metric tonnes)[44]
Prefecture Cultivated in water Cultivated in soil Total
Stem Leafstalk Stem Leafstalk Stem Leafstalk Total
Nagano 226.9 611.4 2.7 14.7 229.6 626.1 855.7
Iwate 8.2 5.5 16.0 488.4 24.2 493.9 518.1
Shizuoka 237.9 129.2 - 138.1 237.9 267.3 505.2
Kochi 0.1 0.1 26.7 45.8 26.8 45.9 72.7
Shimane 3.5 1.7 1.8 42.5 5.3 44.2 49.5
Oita 0.1 0.6 38.8 9.5 38.9 10.1 49.0
Others 32.9 59.7 46.4 76.3 79.3 136.0 215.3
Total 509.6 808.2 132.4 815.3 642.0 1,623.5 2,265.5
2009 wasabi production in Japan (metric tonnes)[45]
Prefecture Cultivated in water Cultivated in soil Total
Stem Leafstalk Stem Leafstalk Stem Leafstalk Total
Shizuoka 295.1 638.2 4.5 232.3 299.6 870.5 1,170.1
Nagano 316.8 739.2 7.2 16.8 324.0 756.0 1,080.0
Iwate 8.8 1.5 2.4 620.5 11.2 622.0 633.2
Shimane 2.4 10.1 9.0 113.0 11.4 123.1 134.5
Oita 0.5 8.9 94.0 0.5 102.9 103.4
Yamaguchi 2.5 2.2 22.5 54.2 25.0 56.4 81.4
Others 65.8 48.1 61.7 108.0 127.5 156.1 283.6
Total 691.9 1,448.2 107.3 1,238.8 799.2 2,687.0 3,486.2

Numerous artificial cultivation[clarification needed] facilities also exist as far north as Hokkaido and as far south as Kyushu. As the demand for real wasabi is higher than that which can be produced within Japan, Japan imports copious amounts of wasabi from the United States, Canada, Taiwan, South Korea, Israel, Thailand and New Zealand.[46] In North America, wasabi is cultivated by a handful of small farmers and companies in the rain forests on the coast of Western Canada, the Oregon Coast,[47] and in areas of the Blue Ridge Mountains in North Carolina and Tennessee.[48] In Europe, wasabi is grown commercially in Iceland,[49] the Netherlands, Hungary, and the UK.[50][51]

Modern cultivars of wasabi mostly derive from three traditional cultivars, 'Fujidaruma', 'Shimane No. 3' and 'Mazuma'. Sequencing of the chloroplastic genome, which is inherited maternally in wasabi, supports this conclusion.[52]

Preparation edit

 
Wasabi on a metal oroshigane grater

Wasabi is often grated with a metal oroshigane, but some prefer to use a more traditional tool made of dried sharkskin (fine skin on one side; coarse skin on the other). A hand-made grater with irregular shark teeth can also be used. If a shark-skin grater is unavailable, a ceramic cheese grater can be an acceptable substitute.[53]

See also edit

References edit

  1. ^ a b c Iwashina Tsukasa [in Japanese] (2016). "Eutrema Japonicum". Curtis's Botanical Magazine. Wiley. 33 (3): 217–225. doi:10.1111/curt.12151. JSTOR 48505819.
  2. ^ a b Miquel, F.A.G. (1866). "Prolusio Florae Japonicae". Annales Musei Botanici Lugduno-Batavi. 2: 69–212.
  3. ^ a b "Eutrema japonicum Koidz. Fl. Symb. Orient.-Asiat. : 22 (1930)". Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. 2022. Retrieved 4 December 2022.
  4. ^ "Wasabia japonica". Multilingual Multiscript Plant Name Database, University of Melbourne. Retrieved 9 August 2016.
  5. ^ a b c Al-Shehbaz, Ihsan A.; Warwick, Suzanne I. (2005). "A Synopsis of Eutrema (Brassicaceae)". Harvard Papers in Botany. Harvard University Herbaria. 10 (2): 129–135. doi:10.3100/1043-4534(2005)10[129:ASOEB]2.0.CO;2. JSTOR 41761810. S2CID 85833186.
  6. ^ a b c Morgan, Lynette (2005). "Hydroponic Production of Wasabi & Japanese Vegetables". In Weller, Thomas; Peckenpaugh, Douglas (eds.). The Best Of Growing Edge International, 2000–2005. New Moon Publishing. ISBN 978-0-944557-05-1. Retrieved 9 August 2016.
  7. ^ わさびの歴史 [History of Wasabi] (in Japanese). Kinjirushi. 2001. Archived from the original on 18 April 2001. Retrieved 9 August 2016.
  8. ^ Frequency of "wasabi" and "sushi" in English-language sources from 1950 to 2008 wasabi vs. sushi in Google Books Ngram Viewer; wasabi tracks sushi, not other Japanese foods
  9. ^ Siebold (1830). "Synopsis Plantarum Oeconomicarum Universi Regni Japonici". Verhandelingen van het Bataviaasch Genootschap van Kunsten en Wetenschappen. 12: 1–74. ISSN 0215-1375.
  10. ^ Maximowicz, C.J. (1873). "Diagnoses plantarum novarum Japoniae et Mandshuriae" [Diagnoses des nouvelles plantes du Japon et de la Mandjourie]. Bulletin de l'Académie impériale des sciences de St-Pétersbourg. 3. 18. cols. 275–296.
  11. ^ Matsumura, J. (1899). "Notulae ad plantas asiaticas orientales". Bot. Mag. (Tokyo). 13 (148): 71–73.
  12. ^ Matsumura, J. (1912). Index plantarum Japonicarum, sive, Enumeratio plantarum omnium ex insulis Kurile, Yezo, Nippon, Sikoku, Kiusiu, Liukiu, et Formosa hucusque cognitarum systematice et alphabetice disposita adjectis synonymis selectis, nominibus Japonicis, locis natalibus. Vol. II(2). Tokyo: Maruzen. p. 161.
  13. ^ Koidzumi, G. (1930). Florae symbolae Orientali-Asiaticae; sive, contributions to the knowledge of the flora of Eastern Asia. Kyoto.{{cite book}}: CS1 maint: location missing publisher (link)
  14. ^ a b "Eutrema japonicum". North Carolina Extension Gardener Plant Toolbox. North Carolina State University. n.d. Retrieved 4 December 2022.
  15. ^ "Definition of rhizome – Merriam-Webster's Student Dictionary". wordcentral.com.
  16. ^ Lowry, Dave (2005). The Connoisseur's Guide to Sushi: Everything You Need to Know about Sushi. The Harvard Common Press. p. 205. ISBN 978-1-55832-307-0. Retrieved 9 August 2016.
  17. ^ "Wasabi – Botanical Notes" in P. N. Ravindran, The Encyclopedia of Herbs and Spices, 2017, ISBN 978-1-78064-315-1, p. 1048
  18. ^ Sultana, Tamanna; Savage, Geoffrey P; McNeil, David L; Porter, Noel G; Martin, Richard J; Deo, Bas (October 2002). "Effects of fertilisation on the allyl isothiocyanate profile of above-ground tissues of New Zealand-grown wasabi". Journal of the Science of Food and Agriculture. 82 (13): 1477–1482. Bibcode:2002JSFA...82.1477S. doi:10.1002/jsfa.1218.
  19. ^ Cordwell, Simon (6 April 2010). "One chefs return home and adventures rediscovering the culinary delights of Tasmania". Tassie Chef. Retrieved 9 August 2016.
  20. ^ "Preparing, Using and Storing Fresh Wasabi". Shima Wasabi. Archived from the original on 29 July 2014. Retrieved 9 August 2016.
  21. ^ Lim, Tong Kwee (2014). "Eutrema japonicum: Edible Plant Parts and Uses". Edible Medicinal and Non-Medicinal Plants: Volume 9, Modified Stems, Roots, Bulbs. Springer. p. 790. ISBN 978-94-017-9511-1.
  22. ^ a b Arnaud, Celia Henry (22 March 2010). "What's wasabi, and is your fiery buzz legit?". Chemical & Engineering News. Vol. 88, no. 12. American Chemical Society. p. 48. ISSN 0009-2347. Retrieved 9 August 2016.
  23. ^ "Wasabi is quite picky about its growing conditions". Real Wasabi. Cullowhee, NC: Real Wasabi, LLC. Retrieved 25 October 2016.
  24. ^ Palmer, J. (1990). "Germination and growth of wasabi (Wasabia japonica (Miq.) Matsumara)". New Zealand Journal of Crop and Horticultural Science/Experimental Agriculture. 18 (2–3): 161–164. Bibcode:1990NZJCH..18..161P. doi:10.1080/01140671.1990.10428089. Retrieved 25 October 2016.
  25. ^ Gittleson, Kim (18 September 2014). "Wasabi: Why invest in 'the hardest plant to grow'?". BBC News. Archived from the original on 19 September 2014. Retrieved 25 October 2016.
  26. ^ Ferdman, Roberto A. (15 October 2014). "The wasabi sushi restaurants serve is pretty much never actual wasabi". The Washington Post. Retrieved 17 January 2018.
  27. ^ Gazzaniga, Donald A.; Gazzaniga, Maureen A. (2007). "Glossary". The No-Salt, Lowest-Sodium International Cookbook. Macmillan. p. 301. ISBN 978-1-4668-1915-3. Retrieved 9 August 2016.
  28. ^ "What's a Good Wasabi Substitute?". 14 June 2018.
  29. ^ "Sushi Items – Wasabi". The Sushi FAQ. Archived from the original on 6 August 2011. Retrieved 9 August 2016.
  30. ^ Mouritsen, Ole G. (2009). Sushi: Food for the Eye, the Body, and the Soul. Springer Science+Business Media. pp. 107–109. ISBN 978-1-4419-0617-5.
  31. ^ Skidmore, Sarah (1 March 2007). "Condiments – Wasabi: real vs. fake". Effingham Daily News. Effingham, IL. Archived from the original on 21 July 2012.
  32. ^ a b Kazuo Ina; Hiroji Ina; Mikako Ueda; Akihito Yagi; Isao Kishima (1989). "ω-Methylthioalkyl Isothiocyanates in Wasabi". Agricultural and Biological Chemistry. 53 (2): 537–538. doi:10.1271/bbb1961.53.537.
  33. ^ a b Hideki Masuda; Yasuhiro Harada; Kunio Tanaka; Masahiro Nakajima; Hideki Tabeta (1996). "Characteristic Odorants of Wasabi (Wasabia japonica matum), Japanese Horseradish, in Comparison with Those of Horseradish (Armoracia rusticana)". Biotechnology for Improved Foods and Flavors. ACS Symposium Series. Vol. 637. American Chemical Society. pp. 67–78. doi:10.1021/bk-1996-0637.ch006. ISBN 9780841234215.
  34. ^ "Condiments – Wasabi: real vs. fake". Archived from the original on 11 July 2011. Retrieved 9 August 2016.
  35. ^ Atsumi, A; Saito, T (2015). "Volatiles from wasabi inhibit entomopathogenic fungi: implications for tritrophic interactions and biological control". Journal of Plant Interactions. 10 (1): 152–157. Bibcode:2015JPlaI..10..152A. doi:10.1080/17429145.2015.1039613. hdl:10297/9349. ISSN 1742-9145.
  36. ^ Zhao, Jianhua; Lin King, John V.; Paulsen, Candice E.; Cheng, Yifan; Julius, David (8 July 2020). "Irritant-evoked activation and calcium modulation of the TRPA1 receptor". Nature. 585 (7823): 141–145. Bibcode:2020Natur.585..141Z. doi:10.1038/s41586-020-2480-9. ISSN 1476-4687. PMC 7483980. PMID 32641835. S2CID 220407248.
  37. ^ Yu, E. Y.; Pickering, I. J.; George, G. N.; Prince, R. C. (15 August 2001). "In situ observation of the generation of isothiocyanates from sinigrin in horseradish and wasabi". Biochimica et Biophysica Acta (BBA) - General Subjects. 1527 (3): 156–160. doi:10.1016/s0304-4165(01)00161-1. PMID 11479032.
  38. ^ Zeuthen, P.; Bøgh-Sørensen, Leif (2003). Food preservation techniques. Woodhead Publishing Limited. p. 12. ISBN 978-1-85573-530-9. Retrieved 9 August 2016.
  39. ^ Levenstein, Steve. "Wasabi Silent Fire Alarm Alerts the Deaf with the Power of Scent". InvestorSpot. Archived from the original on 10 March 2016. Retrieved 9 August 2016.
  40. ^ "Winners of the Ig® Nobel Prize: 2011". Improbable Research. August 2006. Retrieved 22 March 2019.
  41. ^ "Basic Report: 11990, Wasabi, root, raw". National Nutrient Database for Standard Reference Legacy Release. United States Department of Agriculture, Agricultural Research Service. April 2018. Archived from the original on 13 July 2019. Retrieved 11 August 2018.
  42. ^ "Traditional Wasabi Cultivation in Shizuoka, Japan". Food and Agriculture Organization. Retrieved 13 June 2022.
  43. ^ 静岡県 わさび栽培地域 [Shizuoka Prefecture – Wasabi Cultivation Area] (in Japanese). Ministry of Agriculture, Forestry and Fisheries. Retrieved 13 June 2022.
  44. ^ "特用林産物生産統計調査-平成28年特用林産基礎資料 – 2016年 – 3.平成28年主要品目別生産動向 – (16)わさび(生産量)" [Wasabi production]. e-Stat (Statistics of Japan). 13 September 2017. Excel file u008-28-032.xls
  45. ^ "(title in Japanese)" [Wasabi (Production)] (xls) (in Japanese). Portal Site of Official Statistics of Japan. Retrieved 10 August 2016.
  46. ^ Gedye, Lynsey; Mellaerts, Michel Van (10 August 2014). "A Wasabi Growers Story – updated". World of Wasabi. Archived from the original on 29 July 2018. Retrieved 30 June 2017.
  47. ^ Kim Gittleson (18 September 2014). "Wasabi: Why invest in 'the hardest plant to grow'?". BBC News. Retrieved 9 August 2016.
  48. ^ "Can I Grow Wasabi in Western North Carolina?". NC State Extension. 15 March 2010.
  49. ^ "Sustainably". Nordic Wasabi. Jurt Hydroponics. Retrieved 22 March 2019.
  50. ^ Leendertz, Lia (21 May 2015). "The UK farm secretly growing wasabi, the world's most costly veg". The Daily Telegraph. London.
  51. ^ Spijkerman, Catrien (6 July 2019). "Sander stopte als IT-consultant om wasabi te gaan verbouwen in Eigen kas". trouw.nl. Trouw.
  52. ^ Haga, Natsuko; Kobayashi, Masaaki; Michiki, Nana; Takano, Tomoyuki; Baba, Fujio; Kobayashi, Keiko; Ohyanagi, Hajime; Ohgane, Jun; Yano, Kentaro; Yamane, Kyoko (7 October 2019). "Complete chloroplast genome sequence and phylogenetic analysis of wasabi (Eutrema japonicum) and its relatives". Scientific Reports. 9 (1): 14377. Bibcode:2019NatSR...914377H. doi:10.1038/s41598-019-49667-z. PMC 6779752. PMID 31591417.
  53. ^ Andoh, Elizabeth; Beisch, Leigh (2005). Washoku: Recipes From The Japanese Home Kitchen. Ten Speed Press. p. 71. ISBN 978-1-58008-519-9. Retrieved 9 August 2016.

Further reading edit

  • Il Shik Shin; Hideki Masuda; Kinae Naohide (August 2004). "Bactericidal activity of wasabi (Wasabia japonica) against Helicobacter pylori". International Journal of Food Microbiology. 94 (3): 255–61. doi:10.1016/S0168-1605(03)00297-6. PMID 15246236.
  • Miles, Carol; Chadwick, Catherine (1 May 2008). Growing Wasabi in the Pacific Northwest. Washington State University Extension. PNW605.[permanent dead link]
  • A. Depree, J.; M. Howard, T.; P. Savage, G. (June 1998). "Flavour and pharmaceutical properties of the volatile sulphur compounds of Wasabi (Wasabia japonica)". Food Research International. 31 (5): 329–337. doi:10.1016/S0963-9969(98)00105-7.

External links edit

  • Douglas, James A. (1993). "New Crop Development in New Zealand". In Janick, Jules; Simon, James E. (eds.). New crops. Second National Symposium, New Crops: Exploration, Research, and Commercialization. Purdue University, Center for New Crops & Plant Products. Wasabi. ISBN 0-471-59374-5. OCLC 468737540.
  • "Wasabi (Wasabia japonica (Miq.) Matsum.)". Gernot Katzer's Spice Pages. 11 February 2007.
  • "Wasabi: Japanese flavor—Part 1: Seeking 'Japan's No.1'". The Asahi Shimbun. 29 December 2016.
  • "Wasabi: Japanese flavor—Part 2: Exceed Real Ones". The Asahi Shimbun. 9 August 2017.
  • "How to grow wasabi: step-by-step guide". Gardeningnorm. 1 August 2022.