Wasabi, a poweful nutraceutical and functional food

According to Japanese legend, wasabi was discovered hundreds of years ago in a remote mountain village by a farmer who decided to grow it. He reportedly showed it to Tokugawa Ieyasu, a Japanese warlord of the era. Ieyasu, who later became Shogun, liked it so much he declared it a treasure only to be grown in the Shizuoka area.

While cultivation of wasabi in Japan dates to the tenth century, and has since spread to Taiwan, China, New Zealand, Canada, America and elsewhere, this plant has a well deserved reputation of being tricky to grow, largely because it requires cold, pristine water with just the right balance of minerals.

Today, commercial enterprises farm wasabi in mountain environs in the Shizuoka prefecture on Izu peninsula as well as in the Azumino plains of the Nagano prefecture. Effective wasabi horticulture practices are carefully guarded secrets.

With so few producers worldwide, supply of wasabi japonica is quite limited, while demand for real wasabi is growing exponentially and prices reportedly are rising accordingly.

Following is the reported history of "Nishiki-Cho" Wasabi:

Japanese history describes the defeat of the Heike clan in the Dan-noura war, from Bunji years 3 to 5 (from 795 to 797). The survivors fled to other parts of Honshu, Shikoku and Kyushu. Some of them settled near Mount Bahun, located in the upriver district of the Nishiki River. Here they sought a place where they could live in peace. They are said to have been involved in agriculture and hunting while some became craftsmen.

Tradition has it that Wasabi grew wild in the valleys of Mt. Heike, Mt. Mizuo, and Mt. Bahun, in the Kitani-Kyo watershed. The Heike survivors are believed to have gathered wild Wasabi to use as a seasoning for slices of raw yamame (a kind of trout), and raw venison. Many of these survivors were originally noble samurai and were familiar with the life and culture of Kyoto. With this knowledge of Kyoto cuisine, they ate pickled vegetables made from stems and leaves of Wasabi along with many other edible wild plants. This is one of the stories that has made Wasabi the most popular condiment in Japan.

Around the 9th year of the Meiji period, Ichiroku Hashimoto, living in Kitakonishi, first produced a commercial Wasabi product, "Kitani-Kyo" Wasabi. Although the sales figures are not known, he seems to have made a good living through this enterprise, earning one yen, which was an incredible profit for those times. By this business, Wasabi leapt to fame and its cultivation spread in the Kitani-Kyo area. Growing techniques at that time are said to be somewhat primitive; young Wasabi plants were transplanted in simple fields which were created on the banks of a ravine by roughly arranging stones, rather than the current style of preparing fields dedicated only to Wasabi.

In the 9th year of the Taisho period, a new technology of growing Wasabi was devoloped. Wasabi began to be grown in the conglomerate soils alongside mountain streams instead of in flowing water. In spite of the decline in the quality of Wasabi products, this technique attracted a great deal of attention among farmers because of the ability to produce in larger quantities. Wasabi grown using this method became known as Hatake-Wasabi. Fields for Hatake-Wasabi production were then adopted extensively. This forms the main mode of Wasabi farming in Nishiki-Cho. In the Taisho era, Wasabi products were usually harvested two years after planting.

In the year Showa 14, in the former village of Sugane, accelerated cultivation using normal fields was first introduced. This further reduced growing time, controlled diseases, and increased cost effectiveness. This style of cultivation provided the foundation for subsequent improvements in growing methods.

Cherished for decades in the East for its unique flavor and healthful influences, Wasabia japonica is best known as an age-old food pairing with sashimi or sushi dishes that include raw fish. Wasabi is also served as a garnish with Soba noodles and made into pickles, jams, wine and other foods. While distinguishing itself with unique and versatile flavors earns it a special spot in any self-respecting gourmand's pantry, true wasabi also serves up benefits that strengthen immune systems.

Wasabia japonica owes its flavor and healthful benefits in part to a suite of isothicyanates (ITC's) with unique characteristics including powerful anti-bacterial properties, which help mitigate microbial elements or pathogens potentially present. Rich in beta-carotenes and glucosinolates, wasabi also kills some forms of E-Coli and Staphylococcus. Studies also indicate it helps reduce mucous, which has made it the focus of experiments relating to its use in combating asthma and congestive disorders.

The unique ITC spectrum present in wasabi includes long-chain methyl isothiocyanates uncommon in most American's diets. Long-chain methyl ITC's have proven efficacy and potency in supporting natural liver and digestive detoxification functions than other more common types of isothicyanates.

The powerful antioxidant scavanging characterisics of Wasabia japonica are also attracting additional scientific study. As more evidence accumulates, suggesting that glucosinolates and their hydrolysis products are efficacious in reducing cancer risk, legends that refer to wasabi as the "King of Herbs" are gaining credibility.

Wasabi is very low in Saturated Fat, Cholesterol and Sodium. It is also a good source of Vitamin B6, Calcium, Magnesium, Potassium and Manganese, and an excellent source of Dietary Fiber and Vitamin C.

With so much healthful activity going on within one plant, it is not surprising that studies and laboratory tests continue to indicate that wasabi shows promise as a nutraceutical or pharmaceutical component.

Wasabi prefers cool, shady conditions and will sometimes thrive if left undisturbed in misty mountain stream beds. It generally requires a climate with an air temperature between 8°C (46°F) and 20 °C (70°F), and prefers high humidity in summer. Since it is quite intolerant of direct sunlight, wasabi is typically grown under shade cloth or beneath a natural forest canopy.

Wasabia japonica grows in northern Japan, parts of China, Taiwan, Korea and New Zealand. In North America, the rain forests found on the Oregon Coast and in parts of the Blue Ridge Mountains in North Carolina and Tenessee provide just the right balance of climate, sunlight and water quality to grow natural wasabi. Limited success has been achieved by firms using greenhouse and/or hydroponic techniques, but the resulting costs are typically quite high. In Japan, the highest prices are paid for all natural, water grown "sawa" wasabi.

Wasabia japonica plants are slow growing perennials with a rooted, thickened stem (rhizome), long petioles and large leaves. All parts of the wasabi japonica plant, including rhizomes, roots, stems and leaves are harvested, processed and valued for use. The rhizome serves as storage for the plant’s nutrients (similar to a potatoe) and is where the flavors tend to be most concentrated. The appearance of the wasabi rhizome is similar to a brussel sprout stalk after the sprouts are removed. The long stems (petioles) of the Wasabia Japonica plant emerge from the rhizome to grow to a length of 12 to 18 inches and can reach a diameter of up to 40 mm (1 ½ in). They terminate into single heart shaped leaves that, in optimum conditions, can reach the size of a small dinner plate.

Wasabia japonoica plants can take as much as three years to reach maturity. Initially, given the right conditions, the wasabi plant produces robust top and root growth, reaching approximate knee height (2 feet) with an overall width about the same. After this initial establishment phase the rhizome begins to build and store reproductive nutrients. It is this concentration of energy which produces the best flavors so the rhizomes are generally the most valued for culinary purposes. Typically the rhizome will reach a size of six to eight inches long and an inch or so in diameter in approximately twenty four months.

Wasabi leaves and leaf stems (petioles) tend to be brittle. Breakage or damage from animals, field workers or mishandling can cause growth to slow and sometimes even stop for short periods of time.

Under optimum conditions, Wasabia japonica will reproduce itself by seed. In commercial wasabi farms, plant stock is typically extended by replanting small offshoots which characteristically occur as the plant matures.

A member of the brassicae family, Wasabia Japonica owes both its pungency and healthful benefits to a suite of isothiocyanates that occur due to enzymatic activation when the plant tissues are crushed during grating.

Two glucosinolates, sinigrin and glucocochlearin are especially important in wasabi. While both are essentially tasteless compounds on their own, when exposed to the myrosinase enzyme (also present in wasabi in separate plant cells), hydrolosis transmutes these sulfur compounds into pungent allyl isothiocyanate (CH2=CH-CH2-NCS) and sec-butyl isothiocyanate (CH3-CH2-CH(CH3)-NCS), respectively.

The transmutaion process in wasabi occurs within a few minutes of processing, but wasabi flavors are notoriously volatile and dissapate quickly if left exposed to air. This makes wasabi extremely tricky to process, which partially explains why so many producers substitute horseradish for wasabi.

Other trace components identified in the volatile fraction are 6-methylthiohexyl isothiocyanate, 7-methylthioheptyl isothiocyanate and 8-methylthioocytl isothiocyanate. These ω-methylthioalphyl isothiocyanate compounds are concentrated more so in wasabi than other plants and are believed to be responsible for health benefits and the characteristic taste so loved by Japanese connoisseurs.

Source: realwasabi.com