A few weeks ago, I wrote about making sushi at home and mentioned that I was upset when all I could find at the grocery store was imitation wasabi. I decided to look up a little more information about the green stuff and found out that it has some interesting characteristics I wasn't expecting.
Wasabi (wasabia japonica) is a cousin of horseradish; both are rhizomes (root-like stems) in the mustard family. Fresh wasabi is extremely perishable, which accounts for the popularity of imitations. (The version we bought was a mix of horseradish, mustard and food coloring.) It's also very expensive.
Further research revealed that although wasabi is hot, it isn't the same spiciness that results from capsaicin, the source of the heat in chili peppers. While capsaicin produces a burning sensation on the tongue and in the mouth when it's eaten, the active ingredients in wasabi, isothiocyanates, affect the nasal passages more.
It turns out that wasabi is more than just a sushi flavoring. Its place in sushi culture is rooted in the fact that wasabi is believed to have antimicrobial properties that can reduce the risk of food poisoning—a nice perk when eating raw fish. Studies have shown that wasabi root as well as the leaves can prohibit the growth of bacteria that cause food poisoning.
Compounds in wasabi might also help scientists develop a new treatment for pain. Researchers at the University of California at San Francisco studied isothiocynates in wasabi that trigger a reaction in the TRP receptors in nerve cells in our tongues and mouths. These receptors are ultimately responsible for sending a pain signal to the brain. One of the scientists, David Julius, bred mice that lacked one type of TRP receptor and found that the mice didn't react to compounds that contained isothiocynates. Julius also has evidence that the receptor is responsible for to inflammation. A drug that blocked that receptor could conceivably be a powerful painkiller.
But wasabi's potential usefulness doesn't stop there. Japanese scientists harnessed its pungent smell to create a prototype of a smoke alarm for the hearing impaired. The alarm sprays a wasabi extract into the room when smoke is detected. In a preliminary study, 13 out of 14 test subjects awoke within two minutes of the alarm being triggered—one woke up in 10 seconds. Another participant said the alarm reminded him of a bad sushi experience.