Published by City Farmer, Canada's Office of Urban Agriculture

Wasabia Japonica

Pacific Coast Wasabi Ltd. (PCW)
4540 W 3rd Avenue
Vancouver, British Columbia
Canada V6R 1N2
Tel: 604.351.0969
info@wasabia.com
Dr Brian Oates, President and Chief Science Officer
Pacific Coast Wasabi Ltd
cell: 604.351.0969
e-mail: brian.oates@wasabia.com
web site: http://www.wasabia.com

Note: Research which is currently being undertaken by Pacific Coast Wasabi Ltd. includes looking at what would be involved in growing Wasabi in smaller protection structures which could be easily built within an urban environment.

Wasabia Japonica

Fresh Wasabi is a highly prized culinary ingredient used mainly in elite restaurants and sushi bars in Japan. The demand for fresh Wasabi consistently exceeds the supply. So called 'Wasabi' paste is also popular in North American and Japanese restaurants and sushi bars, but what is distributed as Wasabi paste or powder is mostly an imitation product based on horseradish, Chinese mustard and food colouring.

Following several years of development on a prototype farm near Vancouver, Canada, Pacific Coast Wasabi has perfected the techniques for growing semi-aquatic Wasabi in a controlled greenhouse environment and is now expanding into a commercial facility with forty greenhouses in the Lower Mainland of British Columbia. Agriculture Canada has also identified Wasabi as a potential new agricultural crop for British Columbia, and is conducting joint research with Pacific Coast Wasabi to perfect the proprietary techniques used in this controlled environment production. Through these means, Pacific Coast Wasabi is poised to take advantage of this opportunity in the marketplace and provide a steady supply of fresh semi-aquatic Wasabi throughout Asia and the Americas.

Pacific Coast Wasabi (British Columbia, Canada) is now producing fresh Wasabi rhizomes (root-like stems) for sale to the high-end consumer markets in Japan, other Asian markets, North America and via the Internet to a specialized market worldwide. A secondary focus is the development of natural-source bio-chemical and industrial products based on the bioactive compounds present in Wasabi.

What is Wasabi?

The wasabi plant (Wasabia japonica, also incorrectly equated to Eutrema japonica), a member of the cruciferous family, is native to Japan and is traditionally found growing in or by cold mountain streams. The earliest cultivation of wasabi in Japan dates back to the 10th century. The grated 'rhizome' or above-ground root-like stem of this plant has a fiery hot flavor that quickly dissipates in the mouth, leaving a lingering sweet taste, with no burning sensation.

Field Wasabi vrs. Stream Wasabi

There are two main strategies that are used in growing Wasabi. The higher quality Wasabi, both in appearance and taste, grows in cool mountain streams and is known as semi-aquatic or "sawa" Wasabi. Wasabi known as field or "oka" Wasabi is grown in fields under varying conditions and generally results in a lower quality plant, both in appearance and taste.

Varieties of Wasabi

The most popular variety of Wasabi is known as Daruma. The majority of Wasabi grown by Pacific Coast Wasabi is the Daruma variety, but the Mazuma variety is also being produced, for although it is somewhat less attractive in appearance, it has more heat than the Daruma.

Traditional Uses

Wasabi is a staple condiment in Japanese cuisine and is served with sushi and noodles, among other things. The leaves can be dried and used for flavour in foods such as salad dressing, cheese, and crackers; or pickled fresh in sake brine or soy sauce. A Wasabi wine is sold (more as a novelty) in some Japanese specialty stores as well as a higher alcohol content Wasabi liqueur.

Selecting Wasabi

Wasabi powders and pastes which one finds in grocery stores or Japanese restaurants are usually not real wasabi at all. Even the better restaurants generally use so-called wasabi which contains only a very small percentage of lower-grade wasabi or wasabi stems. What is usually known as wasabi is actually horseradish powder (dried and ground regular horseradish), mustard powder, with a little cornstarch and artificial food coloring. Because wasabi plants are peculiar and particular in their needs, real wasabi is more expensive and is considered a rare delicacy.

The Japanese export horseradish-based products as 'wasabi' because in Japanese, horseradish is known as 'seiyo' or 'western' wasabi. When horseradish was first introduced, the Japanese called it 'seiyo' wasabi because it's pungency is similar to wasabi. This is why horseradish is now being exported from Japan under the 'wasabi' name.

When selecting fresh wasabi for grating, choose fresh, cool, un-shriveled roots. When selecting fresh leaves of the wasabi plant use the same guidelines you would use for selecting salad greens; no sogginess or wilt, uniform color, etc.

Preparation

Wasabi adds a unique flavour and heat to foods, and can be served as a spice or an herb in a dish or as a condiment on the side.

Generally, the best results in preparing freshly ground wasabi are obtained by using a sharkskin grater or "oroshi". If a sharkskin grater is not available, ceramic or stainless steel surfaces can be used. Ceramic graters with fine nubs are preferable to stainless steel, but in either case, the smaller and finer the 'teeth', the better.

There are several types and sizes of sharkskin graters available in the Japanese market, usually in specialty food stores or higher-end department stores. Sharkskin mounted on small wooden paddles are generally available in three sizes, with prices ranging between 1,000 and 2,000 yen. Sharkskin mounted on ceramic paddles is slightly more expensive.

Using sharkskin as a tool for grating wasabi has been a practice in Japan since the earliest times, and is still regarded as the preferred method of obtaining the best flavour, texture and consistency in freshly ground wasabi.

Grating wasabi releases volatile compounds, which gradually dissipate with exposure to the air. Using a traditional sharkskin grater and keeping the rhizome at a 90-degree angle to the grating surface generally minimizes exposure to the air. In this way, the volatile compounds are allowed to develop with minimal dissipation. This combination of natural volatiles, consistency and texture distinguish fresh wasabi from the imitation varieties of powdered and paste horseradish, which have been mixed with Chinese mustard and green food colouring.

Once you have grated enough for the first 'session', pile the grated wasabi into a ball and let stand at room temperature for a few minutes to allow the flavor and heat to develop. The flavor will dissipate within a short period, so grate only what will be used within 15 or 20 minutes.

How To Grate Wasabi.

• Rinse the rhizome under cold running water.
• Scrape off any bumps or rough areas along the sides.
• Scrub the rhizome with a stiff brush.
• Cut the rhizome just below the leaf base and inspect the exposed flesh to ensure that it is a uniform green colour.
• Grate the cut end against the grater surface, using a circular motion.
• After use, rinse the rhizome under cold running water. If you are using a sharkskin grater, rinse it under cold running water as well and let it air dry.

Nutrition

As a member of the cruciferous family, wasabi contains the same cancer-fighting isothiocynates as its cabbage cousins. The American National Cancer Institute and the American Cancer Society have studied cruciferous vegetables extensively for years. They recommend that everyone eat several servings from this vegetable family each week to dramatically lower risk of all types of cancer. Researchers believe that one way the substances in cruciferous vegetables help prevent cancer is by helping the body eliminate excess hormones such as estrogen, thus reducing the risk of hormone-related cancers such as breast and prostate cancer.

Wasabi contains a considerable amount of potassium and fair amounts of calcium and vitamin C. However, since it is typically used as a condiment in small amounts, wasabi does not qualify as a significant source of these nutrients.

Natural Source Products and the Chemistry of Wasabia japonica

Medicinal uses for wasabi have been documented in Japan since the 10th century. Some of its chemical components may kill microbes, thus explaining use as an accompaniment to raw fish dishes.

Pacific Coast Wasabi Ltd. believes that there is significant potential in the research and development of products based on the biochemically active compounds found in Wasabia Japonica. The business plan at this stage allows for limited research and development of potential in this area, but in the event that more focused research is required, additional funding will be necessary. It is within this context that an Initial Public Offering may be contemplated after an initial period of research and development.

Wasabi's stature as a highly prized condiment in Japanese cuisine is well known. However, a fact that is not widely recognized or appreciated is that Wasabi contains numerous bio-chemically active compounds, mainly from the isothiocyanate family, that have medicinal, pharmaceutical or industrial applications. These exciting applications are only just beginning to be investigated, most likely because of the plant's high commercial value and its scarcity. For example, Pacific Coast Wasabi Ltd. has a letter on file from a Japanese scientist[1] who said that true Wasabi was too expensive for him to continue his research investigating Wasabi's role as an anticancer agent. Because Pacific Coast Wasabi Ltd. grows its own Wasabi, price and availability will not be factors during the development of secondary products.

Medicinally, the most important feature of Wasabi is that it contains compounds effective against cancer. Extracts from Wasabi have been shown repeatedly to be effective against stomach cancer cells (Tanida et al. 1991, Fuke et al. 1994, Fuke et al. 1997, Ono et al. 1996, Shin and Lee 1999). Other types of cancer, including breast, forestomach and colon, may also be treated by compounds known to exist in Wasabi (Wattenberg 1977, 1981) but these have not yet been studied.

Compounds found in Wasabi are also effective when used in other medical situations. The isothiocyanates of Wasabi inhibit platelet aggregation (Kumagai et al. 1994) which works as an effective anticoagulant. These anticoagulant properties could be used in the treatment of the elderly and during surgery where preventing platelet aggregation is vital. Recently, it was shown that Wasabi contained compounds (not determined which ones) that may be effective against diarrhea (Nakayama et al. 1998). And lastly, some secondary metabolites found in Wasabi may be effective antiasthmatic (Dorsch et al. 1985) and anti-inflammatory (Depree et al. 1998) agents.

Depree, J. A., Howard, T. M., and Savage, G. P. recently (1999) reported in Food Research International (31:329-337) in an article entitled "Flavour and pharmaceutical properties of the volatile sulphur compounds of Wasabi (Wasabia japonica)" as follows:

'The anti-inflammatory effects and inhibition of platelet aggregation by omega-methylthioalkyl isothiocyanates is perhaps of more interest given the rapid action of the compounds and the low levels at which they are effective. This could potentially be used to counter inflammatory conditions such as asthma or even anaphylaxis. The ability of the wasabi isothiocyanates to inhibit platelet aggregation could also have medical applications, particularly in the treatment of heart attacks. Further work on the pharmacology of these compounds and their possible medicinal use, as well as other medicinal properties of wasabi seems warranted.'

'With the increasing international market in wasabi and wasabi-based food products, its potential as a medicinal herb, and the possibility of useful pharmaceutical products, cultivation of wasabi both within and outside of Japan seems likely to increase in the foreseeable future. This is certain to lead to an increase in both demand and funds for research into these and other aspects of wasabi.'

Potential industrial applications for the bioactive compounds of Wasabi are antibiotics (this feature of course also has medicinal value), fungicides and as a wood preservative. It has long been known that Wasabi contains natural antibiotics and this feature helped bring Wasabi into Japanese cuisine as long as 1300 years ago. This knowledge has been scientifically validated in studies (Hasegawa et al. 1998, Ono et al. 1998, Shin and Lee 1999) that have shown Wasabi extracts to inhibit the growth of food poisoning types of bacteria. Recent research, done in Canada (Soledade et al. 1998) has shown that Wasabi contains antifungal metabolites that render the plant resistant to virulent isolates of the blackleg fungus. This fungus can devastate commercially important crops such as the oilseed plants rapeseed and canola. Thus, there is a potential here to develop a natural (organic) fungicide for this industry.

Lastly, there have been indications that Wasabi extracts may be effective natural wood preservatives. Several years ago, the Wasabi Kyokai (Japanese National Wasabi Association) approached a major Canadian Industry Association to see if there would be any Canadian interest in participating in the development of a "natural source" Wasabi-based wood preservative as an alternative to the toxic chemically based wood preservatives, which continue to be methodically regulated out of use. At the same time, the Wasabi Kyokai also expressed an interest in looking at British Columbia as a potential source of cold fresh water mountain streams for traditional Wasabi production. There was no Canadian-side follow-up at the time.

References

Depree J. A., Howard T. M., and Savage G. P. 1998. Flavour and pharmaceutical properties of the volatile sulphur compounds of Wasabi (Wasabia japonica). Food Research International, 31:329-337.

Dorsch W., Adam O., Weber J., and Ziegeltrum T. 1985. Antiasthmatic effects of onion extracts-Detection of benzyl- and other isothiocyanates (mustard oils) as antiasthmatic compounds of plant origin. Eur. J. Pharmacology, 107:17-24.

Fuke Y., Ohishi Y., Iwashita K., Ono H., and Shinohara K. 1994. Growth suppression of MKN-28 human stomach cancer cells by Wasabi (Eutrema wasabi Maxim.). Journal of the Japanese Society for Food Science & Technology, 41:709-711.

Fuke Y., Haga Y., Ono H., Nomura, T., and Ryoyama K. 1997. Anti-carcinogenic activity of 6-methylsulfinylhexyl isothiocyanate-, an active anti-proliferative principal of Wasabi (Eutrema wasabi Maxim.). Cytotechnology, 25:197-203.

Hasegawa N., Matsumoto Y., Hoshino A., and Iwashita K. 1999. Comparison of effects of Wasabia japonica and allyl isothiocyanate on the growth of four strains of Vibrio parahaemolyticus in lean and fatty tuna meat suspensions. International Journal of Food Microbiology, 49:27-34.

Kumagai H., Kashima N., Seki T., Sakurai H., Ishii K., and Ariga T. 1994. Analysis of volatile components in essential oil of upland Wasabi and their inhibitory effects on platelet aggregation. Bioscience Biotechnology and Biochemistry, 58:2131-2135.

Nakayama H., Suzuki T., and Suzuki Y. 1998. Effect of Wasabi on ion secretion in guinea pig colon. Nippon Nogeikagaku Kaishi, 72:499-507.

Ono H., Adachi K., Fuke J., and Shinohara K. 1996. Purification and structural analysis of substances in Wasabi (Eutrema wasabi Maxim.) that suppress the growth of MKN-28 human stomach cancer cells. Journal of the Japanese Society for Food Science & Technology, 43:1092-1097.

Ono H., Tesaki S., Tanabe S., and Watanabe M. 1998. 6-methylsulfinylhexyl isothiocyanate and its holologues as food-originated compounds with antibacterial activity against Escherichia coli and Staphylococcus aureus. Bioscience Biotechnology Biochemistry, 62:363-365.

Shin I. S., and Lee J. M. 1998. Study on antimicrobial and antimutagenic activity of horseradish (Wasabia japonica) root extracts. Bulletin of the Korean Fisheries Society, 31:835-841.

Soledade M., Pedras C., and Sorensen J. L. 1998. Phytoalexin accumulation and antifungal compounds from the crucifer Wasabi. Phytochemistry, 49:1959-1965.

Tanida N., Kawaura A., Takahashi A., Sawada K., and Shimoyama T. 1991. Suppressive effect of Wasabi (pungent Japanese spice) on gastric carcinogenesis induced by MNNG in rats. Nutrition and Cancer, 16:53-58.

Wattenberg L. W. 1977. Inhibition of carcinogenic effects of polycyclic hydrocarbons by benzyl isothiocyanate and related compounds. Journal of the National Cancer Institute, 58:395-398.

Wattenberg L. W. 1981. Inhibition of carcinogen-induced neoplasia by sodium cyanate, tert-butyl isothiocyanate and benzyl isothiocyanate administered subsequent of carcinogen exposure. Cancer Research, 41:2991-2994.

[1] Dr N. Tanida, Hyogo College of Medicine, Hyogo, Japan, in a letter dated 6th of July 1993 to Dr Brian Oates.

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