Estimated reading time: 5 minutes
The freshly grated wasabi hides a secret known as the Wasabi Kick which produces a zingy heat when consumed with your favourite food which does not occur with fake wasabi. This pale green grated powder is known as Japanese horseradish, but this is not the same as the horseradish which complements your roast dinner. It is a distant cousin and is formally known as Wasabia japonica – a member of the Brassicaceae family. Wasabi is closely related to cabbage, cauliflower, broccoli and mustard.
Wasabi is cultivated in Japan alongside mountain stream beds enabling the production of a vast carpet of unique plants. They are long-stemmed with heart-shaped leaves and white flowers which branch from a knotted, thick, swollen stem, known as a rhizome.
The two main methods of growing wasabi involve the usage of semi-aquatic conditions to produce the sawa type (grown in water) and in fields to give oka wasabi (grown in soil). Usually, under sawa conditions, larger rhizomes are formed than in oka grown wasabi. However, both give that extraordinary wasabi kick.
The wasabi plant is tough to cultivate and it flourishes best in mountain stream water. At Wasabi Crop, we have developed expertise through continuous chemistry to generate wasabi rhizomes, leaves and stems for all our customers.
Real wasabi is expensive to cultivate and the majority is consumed in Japan: this is the major reason why most people have not tasted real wasabi. Most wasabi sold in supermarkets, sushi bars and restaurants are fake. This fake wasabi usually consists of horseradish, mustard, starch and green food colouring.
In most cases, when wasabi is ordered with your food, a squirt of ‘bright’ green toothpaste-like material is placed on your plate – and the customer is under an illusion because it is almost certainly fake wasabi!
Genuine wasabi is grated in front of the customer to produce the wasabi powder. The best grater to use is the sharkskin paddle because it can finely grate the rhizomes. This grating process initiates chemical reactions through the mechanical damage of the cells inside the rhizome producing volatile compounds, rich in flavour.
The heat usually produced lasts for about 20 minutes and this is usually enough time to experience the wasabi kick. This event does not happen with horseradish – which can retain its potency and sharp flavour for many days. The chemistry of horseradish and wasabi are similar but each have different amounts of naturally flavoured compounds to each their individual, unique flavour profile. The central component in horseradish and wasabi rhizomes are glucose sulphur-containing organic compounds known as thio-glucosides.
During the grating and maceration of the rhizome, the cell walls break releasing the thio-glucosides and the enzyme called myrosinase.
What is the role of myrosinase?
Essentially, the main function of myrosinase is to break down the thioglucosides into glucose and by a chemical rearrangement called the Lossen Rearrangement generating varying amounts of isothiocyanate compounds.
So, during this process, the horseradish and wasabi will both produce different concentrations of the isothiocyanates. Interestingly, horseradish generates about 10% less of the total isothiocyanates per kilogram of horseradish compared to wasabi.
The major isothiocyanate compound present in wasabi is called allyl isothiocyanate and this association is REAL WASABI producing a pungent zingy wasabi kick. Another component is called 2-phenylethyl isothiocyanate and this is surprisingly found in horseradish. Other compounds include 6-methylthiohexyl isothiocyanate, 7-methylthioheptyl isothiocyanate and 8-methylthiooctyl isothiocyanate.
Studies have shown that isothiocyanates inhibit microbe growth and provide great benefits for preserving food against spoilage and suppressing oral bacterial growth.
More on allyl isothiocyanate!
The allyl isothiocyanate is responsible for the wasabi kick generating heat when consumed and this is different from that produced by chillies and peppers.
In summary, the wasabi experience is related to the amount of allyl thiocyanate consumed. So, eat and enjoy plenty of freshly grated wasabi. The only solution if you can not manage the wasabi kick is just to control it with the consumption of food and/or beverages.
Real wasabi is expensive and the majority of it is consumed in Japan – here at Wasabi Crop we will give you the opportunity to buy wasabi varieties and let’s not forget the delicious leaves and stems for your stir-fries and salads.
Enjoy your fresh wasabi – providing new foods for your table!
I’m Sofia Kitson, the Wasabi Crop Blogger. My interests are writing articles on growing and cooking with wasabi.