Wasabi

For other uses, see Wasabi (disambiguation).

Wasabi
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Brassicales
Family:	Brassicaceae
Genus:	Eutrema
Species:	E. japonicum
Binomial name
Eutrema japonicum Matsum.

Wasabi (わさび（山葵）, earlier 和佐比; Eutrema japonicum/"Wasabia japonica") is a plant of the Brassicaceae family, which includes cabbages, horseradish, and mustard. It is also called Japanese horseradish, although horseradish is a different plant (which is generally used as a substitute for wasabi, due to the scarcity of the wasabi plant). Its stem is used as a condiment and has an extremely strong pungency more akin to hot mustard than the capsaicin in a chili pepper, producing vapours that stimulate the nasal passages more than the tongue. The plant grows naturally along stream beds in mountain river valleys in Japan. The two main cultivars in the marketplace are E. japonicum 'Daruma' and 'Mazuma', but there are many others. The origin of Wasabi cuisine has been clarified from the oldest historical records, It takes its rise in Nara prefecture.

Uses

Fresh wasabi stems for sale at Nishiki Market in Kyoto

Wasabi crop growing on Japan's Izu peninsula

Wasabi is generally sold either as a stem, which must be very finely grated before use, as dried powder in large quantities, or as a ready-to-use paste in tubes similar to travel toothpaste tubes. Because it grows mostly submerged, it is a common misconception to refer to the part used for wasabi as a root or sometimes even a rhizome: it is in fact the stem of the plant, with the characteristic leaf scar where old leaves fell off or were collected.

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. In sushi preparation, sushi chefs usually put the wasabi between the fish and the rice because covering wasabi until served preserves its flavor.

Fresh wasabi leaves can be eaten, having the spicy flavor of wasabi stems.

Legumes (peanuts, soybeans, or peas) may be roasted or fried, then coated with wasabi powder mixed with sugar, salt, or oil and eaten as a crunchy snack.

Surrogates

Wasabi is difficult to cultivate, and that makes it quite expensive. Due to its high cost, a common substitute is a mixture of horseradish, mustard, starch and green food coloring. Outside of Japan, it is rare to find real wasabi plants. Often packages are labeled as wasabi while the ingredients do not actually include wasabi plant. Although wasabi and horseradish are similar in taste, wasabi is green and hotter. In Japan, horseradish is referred to as seiyō wasabi (西洋わさび^?, "western wasabi"). In the United States, true wasabi is generally found only at specialty grocers and high-end restaurants.

Chemistry

The chemical in wasabi that provides for its initial pungency is the volatile allyl isothiocyanate, which is produced by hydrolysis of natural thioglucosides (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. The same compound is responsible for the pungency of horseradish and mustard.

The unique flavor of wasabi is a result of complex chemical mixtures from the broken cells of the plant, including those resulting from the hydrolysis of thioglucosides into glucose and methylthioalkyl isothiocyanates:

• 6-methylthiohexyl isothiocyanate
• 7-methylthioheptyl isothiocyanate
• 8-methylthiooctyl isothiocyanate

Research has shown that such isothiocyanates inhibit microbe growth, perhaps with implications for preserving food against spoilage and suppressing oral bacterial growth.

Because the burning sensations of wasabi are not oil-based, they are short-lived compared to the effects of chili peppers, and are washed away with more food or liquid. The sensation is felt primarily in the nasal passage and can be quite 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 vapor sprayed into his sleeping chamber. 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.

Nutritional information

One hundred grams of wasabi stem contains:

• Energy: 460 kJ (109 kcal)
• Fat: 0.63 g
• Carbohydrates: 23 g
• Fiber: 7.8 g
• Protein: 4.8 g

Cultivation

A drawing of a wasabi plant, published in 1828 by Iwasaki Kanen

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

• Izu peninsula, in Shizuoka prefecture
• Nagano prefecture
• Iwate prefecture

2009 wasabi production in Japan (metric tonne)

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

There are also numerous artificial cultivation facilities as far north as Hokkaido and as far south as Kyushu. As the demand for real wasabi is very high, Japan imports an amount from China, Taiwan, and New Zealand. In North America, a handful of companies and small farmers cultivate Wasabia japonica.

Preparation

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 with fine skin on one side and coarse skin on the other. A hand-made grater with irregular teeth can also be used. If a shark-skin grater is unavailable, ceramic is usually preferred.

Etymology

The two kanji characters "山" and "葵" do not correspond to their pronunciation: as such it is an example of gikun (meaning, not sound). The two characters actually refer to the mountain Asarum, as the plant's leaves resemble those of a member of Asarum species, in addition to its ability to grow on shady hillsides. The word, in the form 和佐比, appeared in 918 in The Japanese Names of Medical Herbs (本草和名 Honzō Wamyō). Spelled in this way, the particular kanji are used for their phonetic values only, known as ateji (sound, not meaning – opposite of gikun).

See also

• List of condiments
• List of delicacies
• Satoyama

External links

• Wasabi Information – Purdue University Agriculture
• Wasabi (Wasabia japonica (Miq.) Matsum.) – Spice Pages