Wasabi, known as Wasabia japonica or Japanese horseradish, is an aromatic medicinal plant and is a member of the Brassicaceae family. Wasabi plants are native to Japan and Sakhalin Island in the Pacific Ocean. In Japan, wasabi plants are found growing naturally in the gravel beds of mountain streams and require the shade of trees for them to thrive. However, wasabi can be cultivated in either water referred to as Sawa wasabi which means water wasabi or grown on land known as Hatake wasabi to produce different varieties.
Therefore, approximately 60% of all wasabi grown in Japan is cultivated in Nagano and Shizuoka prefectures due to these stringent conditions. In the Azumino region, the Daio Wasabi Farm uses black cloth to shade the wasabi plants in the irrigated water streams of the fields.
Interestingly, wasabi was first referenced in a dictionary of medicinal herbs called the Honzowamyo (Names of Living Things), which was compiled in Japan in 918. However, wasabi was not often consumed very much at the beginning, and it was only in the 13th century that wasabi was becoming more popular. For example, a recipe book from 1489 describes the preparation of dipping carp sashimi in wasabi vinegar. Furthermore, during the 17th century, the wasabi root became a popular spice, especially being added to soba noodles. However, during the period from 1818-1830, freshly grated wasabi was being served with sushi and from this point, sushi and soba became very popular in Japanese cuisine.
These wasabi plants have heart-shaped green leaves and are used as herbs, while the wasabi rhizome is a spice that brings a unique flavour to cooking. So, you have received your fresh wasabi rhizome from the Wasabi Crop Shop and you cannot wait to experience the wasabi kick. After grating a good portion of the wasabi rhizome, you place a dab of the light green paste onto a piece of fresh salmon. You then bite into the salmon smothered in real fresh wasabi paste and you immediately feel your sinuses explode with the fantastic zing fresh flavours to give a strange and comfortable feeling of your body.
The Wasabi rhizome can take up to 3 years to reach maturity compared to horseradish which takes eight months. This is why wasabi root is so rare outside Japan because wasabi is challenging to grow and harvest.
However, at Wasabi Crop, we have grown this superfood and can supply our customers’ fresh wasabi rhizomes and wasabi leaves. Also, you can grow your own wasabi rhizomes; you can purchase wasabi plants from the Wasabi Crop Shop.
Have you ever visited a sushi bar and had a dab of bright green wasabi squeezed from a plastic tube. You will be surprised to know that you have been eating fake wasabi. Sorry to disappoint you, you heard it right – fake wasabi. All this time, you have been dabbing on your expensive meal, a mixture of horseradish, mustard, and green food colouring. If the wasabi is not grated in front of you, this is a good sign that it is fake.
Wasabi adds flavour to your food and has medicinal properties associated with the whole plant. The Japanese diet has always been associated with good health amongst its people. Currently, scientific research is beginning to understand why wasabi is a superfood and a powerful herbal medicine.
The wasabi plant’s analysis has found that it contains a mixture of protein, fibre and vitamins, especially B6 (pyridoxine) and C (ascorbic acid). In addition to the minerals calcium, manganese, magnesium and potassium.
Wasabi is similar to many plants in the mustard family in that it contains a group of compounds called glucosinolates. These components are enzymatically broken down to produce bioactive isothiocyanates (ITCs) during the mastication process in the mouth. This process causes the cells to be disrupted and release the enzyme called myrosinase (sinigrinase), which performs a Lossen rearrangement to release the ITC. Also, myrosinase is an enzyme found in nature that catalyzes the hydrolysis of a class of compounds called glucosinolates. It is worth noting that other plants which produce myrosinase include white mustard, garden cress and daikon.
Interestingly, real wasabi releases the volatile compound allyl isothiocyanate that interacts with your wasabi receptors. A receptor is usually found on the surface of mammalian cells. It conveys information on how the cell functions and responds to the substrate binding to the receptor, such as allyl isothiocyanate. The wasabi receptor is called the TRPA1 (transient receptor potential ankyrin 1) and is related to the chilli peppers receptor called TRPV1 (transient receptor potential vanilloid 1) that binds capsaicin. The chemical capsaicin (8-methyl-N-vanillyl-6-nonenamide) is what gives the spice to chillies.
When you eat chillies, capsaicin causes a reaction through contact with the tongue. However, the volatile chemical allyl isothiocyanate released from the wasabi rhizome grating goes up your nose and interacts with the wasabi receptors, resulting in a wasabi brain rush sensation.
The TRPV1 and TRPA1 channels are members of the TRP (transient receptor potential) superfamily of non-selective cation channels and are involved in pain and neurogenic inflammation. These receptors respond to onions, mustard, tear gas, cigarette smoke and car exhausts. Therefore, studying the wasabi receptor will lead to more effective pain relief for chronic pain sufferers.
Another exciting discovery was that the smell of wasabi had been shown to be the most effective at waking you up quickly. Therefore, wasabi was shown to be used in smoke alarms and was able to notify deaf people that there was a fire. It worked by releasing a mist of wasabi containing allyl isothiocyanate. Furthermore, the wasabi smoke alarm won the Annals of Improbable Research’s Ig Nobel Prize in Chemistry in 2011.
Various studies have shown that several isothiocyanates are present in wasabi and horseradish. The horseradish contained 1.9 grams total isothiocyanate/kg, whereas wasabi contained nearly 10% more (2.1 g per kg of rhizome). Furthermore, it has been shown that the allyl isothiocyanate is present at different levels in both wasabi and horseradish. However, 2-phenylethyl isothiocyanate was only identified in horseradish. It was concluded these different isothiocyanates were probably responsible for the various flavours between wasabi and horseradish. All the isothiocyanates detected were present higher within the wasabi. Also, studies have shown that the isothiocyanates present in wasabi have antibacterial and anti-inflammatory properties.
However, all of the Wasabi japonica may contain over twenty ITCs and therefore contribute to different medicinal properties. One of the ITCs of particular interest and is more prominent in the wasabi plant is 6-methylsulfinylhexyl isothiocyanate (6-MITC) which may possess anti-inflammatory effects and helping to control allergies and asthma-related diseases. The 6-MITC can inhibit lipoxygenase, cyclooxygenase, and cAMP phosphodiesterases that are both involved in the body’s inflammatory processes. These ITCs in Wasabi are worth investigating for the treatment of eczema and these compounds have shown to inhibit platelet aggregation, which could be a potential treatment for heart problems.
In Japan, there has been a long tradition of sushi served with freshly grated wasabi. This food pairing was because the ITCs can inhibit several strains of bacteria, yeast, and mould. The antibacterial effect is probably due to the 6-MITC and studies have shown that wasabi is effective against Staphylococcus aureus and Escherichia coli. Also, the ITCs found in wasabi was able to inhibit is Helicobacter pylori. This bacteria is responsible for gastric ulcers and stomach cancers.
The isothiocyanates have shown to be active against cancerous cells and may work by inhibiting enzymes responsible for the metabolic activation of producing carcinogenic compounds. Also, the ITCs do not harm healthy cells and be effective against certain types of tumour cells. Moreover, other interesting medicinal properties of ITCs is their ability to protect nephrons in diabetes patients and antioxidant properties
Wasabi is an exciting superfood and is beneficial for your health due to its nutritional and medicinal properties. So why not try some fresh wasabi?
I’m Sofia Kitson, the Wasabi Crop Blogger. My interests are writing articles on growing and cooking with wasabi.