Wasabi, a vegetable native to Japan, is traditionally served with raw fish dishes such as sashimi. While it has antibacterial properties, its primary role is to enhance the flavor of the fish. Japan has numerous aromatic vegetables, including wasabi, ginger, myoga, green onions, and sansho pepper, among others. Each possesses a unique aroma and aromatic compounds. Adding these to other foods or mixing them during cooking stimulates the taste buds, significantly enhancing the flavor of the dish. Since all these aromatic vegetables have antibacterial and sterilizing effects, they are often served with sashimi and similar dishes.
The pungent flavors of these aromatic vegetables can be broadly categorized into three types: the sharp, stinging heat of wasabi; the fiery, burning heat of chili peppers; and the numbing, tingling heat of sansho peppers. Each type has different components responsible for its distinct heat. Let’s examine them individually.
The pungent component in wasabi is a substance called sinigrin. Sinigrin itself has no pungency, but when the cells are broken down by grinding or similar processes, exposing sinigrin to oxygen in the air causes the enzyme myrosinase to produce a substance called allyl isothiocyanate. This allyl isothiocyanate is the pungent component in wasabi and Leaf mustard or Mustard greens. Wasabi is a plant in the Brassicaceae family, and sinigrin is a substance widely found in vegetables of this family. The pungent taste in other Brassicaceae plants like Mustard cress or Daikon mustard also comes from sinigrin. Wasabi simply contains a particularly high amount of it.
There are two types of wasabi: Sawa wasabi and Yama wasabi. Sawa wasabi is the common, green variety you see most often. Yama wasabi, on the other hand, is the horseradish served with roast beef and similar dishes. Although both are wasabi, their shape and color are completely different. Yama wasabi resembles spicy radish and is used as the base for prepared wasabi paste and powdered wasabi. It has low moisture content and is large in size, resulting in a high yield, making it well-suited for processed products.
Wasabi has been consumed since the Heian period, with records indicating it was eaten mixed into dishes like grated yam broth. At that time, there seemed to be established rules: carp sashimi was served with wasabi vinegar, sea bream sashimi with ginger vinegar, and sea bass sashimi with tade vinegar. Given the era’s hygiene concerns, it’s likely a considerable amount of aromatic vegetables were used. Wasabi began to be eaten with soba noodles, now commonplace, around the Edo period. Originally, spicy radish was served alongside soba. However, when radish was unavailable, wasabi was substituted. It is said that wasabi became a staple because it masked the distinctive fishy odor of the bonito flakes in the soba dipping sauce. Generally, it’s hard to imagine wasabi replacing radish.
Next, when it comes to chili peppers in Japan, Takanotsume (Bird’s eye chili) and Shichimi togarashi (seven flavor chili pepper) are common. Bird’s eye chili is often added to preserved foods such as rice bran pickles, and it has also been traditionally kept for medicinal purposes. This is because Bird’s eye chili also has antibacterial properties. It offers significant health benefits, burning body fat, warming the body, opening pores, and promoting sweating. It is especially effective in winter for raising body temperature. In summer, eating spicy food induces sweating, allowing moisture to evaporate along with body heat, thereby lowering temperature. The capsaicin in Bird’s eye chili promotes fat breakdown and accelerates the breakdown of glycogen in the liver and muscles. Consequently, it not only stimulates the stomach and improves blood circulation but also activates digestive movements within the internal organs, boosting appetite. It is effective during winter when lack of exercise reduces appetite, and also combats summer fatigue-induced loss of appetite.
Chili peppers have also been widely used in preserved foods like pickles, miso, and tsukudani. Their intense pungency and antibacterial properties enhance the shelf life of ingredients, making them a cherished seasoning that supports Japanese dietary habits.
The numbing spiciness of sansho comes from a compound called sanshool. Sanshool increases gastric acid secretion, making it a perfect match for rich, fatty dishes like eel. It also contains an aromatic compound called diterpene, which boosts immunity and enhances antioxidant effects. The name “sansho” (山椒) itself comes from the mountain-scented fruit that is spicy like pepper. Sansho is known as Japanese pepper in English, making it an iconic spice of Japan.
Furthermore, sansho has been utilized in diverse dishes by selecting either the berries or leaves. It is also used in preserved foods like tsukudani and chirimen sansho, enhancing ingredient preservation through its refreshing aroma and antibacterial properties. Additionally, in ancient times, it was valued medicinally as the herbal remedy “Shokushō (蜀椒),” prized for its stomach-strengthening and anthelmintic effects.
In other words, the practice of always serving wasabi with sushi and sashimi is not merely a custom. It is a tradition born from the convergence of scientific reasons like sterilization and antibacterial properties, the culinary ingenuity of maximizing the umami of fish, and the wisdom cultivated by the Japanese people throughout history. Wasabi is more than just a condiment; it is passed down to modern dining tables as a “key component” that elevates the dish’s overall quality.