The Basics of Japanese Pepper
A Spice with Uncanny Properties
It’s a light brown powder that comes in a small glass bottle with a green label. It appears on the table in Japanese restaurants where grilled eel is served.
Sansho, 山椒 translated as Japanese Pepper, is used by some people to sprinkle on top of Japanese style grilled chicken or eel, and that’s about it. A strictly limited niche spice.
Or is it? Recent research on Sansho shows that the spice has some alarming — even electrical properties — that could give it a much wider role in cooking. And it could have some important health benefits as well. We’ll return to this shortly.
You may already have a bottle of Sansho in your home, if you make grilled eel or have discovered that Sansho is good on yakitori or other Japanese style grilled chicken.
Sansho, or Japanese Pepper, is the ground-up berry of the prickly ash. The same plant also yield a fragrant leaf called kinome, which is used as a garnish or tsuma for wrapping sashimi.
It turns out that Sansho has an ancient history, and is one of the oldest spices known to have been used to flavor foods. Today its role is strictly limited to sprinkling on a few foods in Japanese kitchens and restaurants.
What other uses does Sansho have? What are its nutritional properties? We’ll see shortly.
Sansho is described as a brown Japanese seasoning powder. 
Articles on gourmet cooking say Sansho has a peppery lemon-like flavor and leaves a tingling sensation if put directly on the tongue. This tingling is a clue to its special properties, as we’ll see in a moment. 
Sansho is sometimes confused with Sichuan Pepper and some cooks say the two are interchangeable. Sichuan Pepper comes from a different but related plant, and they do have different uses in cooking. We’ll come back to that.
Despite its English name, Japanese Pepper or Sansho is not actually a member of the Pepper or Capsicum family, but is is a spice with some pepper-like features.
Japanese people have been using Sansho to flavor their food for a long time, in fact since the Jomon Period, which archeologists say goes back as far as 12,500 BCE. So the use of Sansho in Japan is truly ancient.
Sansho is one of the earliest food seasonings we know about in the ancient world. In terms of world history, this is the time of the Olmecs, or Ramses II, Moses, and the early Shang Dynasty in China.
Sansho even appears in a Japanese proverb: “Although the Sansho berry is small, it is peppery.” 
Recent research in Japan and the United States show that Sansho has some unusualk properties. And it has some unusual nutritional values and uses in cooking.
Rich Source of Vitamin A: Japanese nutritionist Fumiko Matsumoto found that Sansho is a good source of
- Vitamin A
- calcium, phosphorous, and potassium 
Professor Nobuhiro Mano of Nihon University’s Biological Research Center studied Sansho for six years and discovered that it contains a compound that is toxic in larger quantities. This finding is related to some other important discoveries about Sansho. 
Professor Kikue Okubo of Ochanomizu Women’s University in Tokyo investigated the properties of Sansho which derive from its toxic compound and how this affects taste.
She found that the pepperiness of Sansho, as measured by the Scoville Scale, was only 1/200th of that of Capsicum for the same weight.  For her studies, Okubo used the pepper commonly known in Japan as Togarashi to present Capsicum.
Okubo had test subjects, who were wired up to measure their brain waves, take quantities of Sansho and Capsicum by mouth and then measured the effect on their nervous systems. She found that caking Capsicum by mouth directly stimulated brain waves by 25 percent within 20 minutes of taking it.
The stimulation after taking Sansho was 29 percent. But how is it possible that a substance only 1/200th as peppery as Capsicum could have an even greater stimulative effect?
Okubo found the answer lies in how the two peppery substances affect the nervous system. Capsicum creates a general pain-like stimulation on the nervous system. Sansho, on the other hand, affects both the tactile system of the brain and the centers that perceive the various flavors — salty, sweet, bitter, etc.
Sansho acts as a general stimulant to the taste receptors in the brain, increasing flavor and aromas of foods in general. Because it enhances the perception of saltiness, foods flavored with tiny amounts of Sansho taste salty, even though no extra salt has been added.
Okubo had subjects chew small amounts of fresh Sansho berries five minutes before eating a variety of foods. They all reported greatly increased flavor and aroma when tasting a wide range of food.
The effect of Sansho is related to its toxic component, which has a strong effect in what the Chinese call the mouth-numbing effect, called in Chinese ma la. . This effect has been discussed by experts in Chinese cuisine, especially Sichuan cooking, like Fuchsia Dunlop. In Japanese, the numbing effect is called ma mi.
All this is not surprising when you consider that Sansho is a pretty close relative of the plant that yields Sichuan Pepper.
Sansho has another, amazing property, that is related to its numbing effect and its impact on the taste receptors of the tongue and taste centers of the brain. The herb is electric! Studies at the University of California in 2008 show that the herb contains enough electric force to produce “mild electric shock.”
In fact, powdered Sansho can light a flashlight battery from the amount contained in a large saucer full of the herb. A larger quantity — say a heaping plate full — has enough electric current to light a 9 volt battery.
The electric effect of Sansho is related to its toxic compound. Enough of the effect lingers in the powdered spice to stimulate the tongue when the herb is placed on the tongue.
Sansho’s unusual properties also affect the body’s perception of flavors. All this research has led to some unusual applications for Sansho in cooking. We cover this topic in a separate Article.
For Further Information:
 “Sansho.” article, Wikipedia — http://en.wikipedia.org/wiki/Sansh%C5%8D
 “Sansho Pepper,” The Japanese Kitchen — http://thejapanesekitchen.com/2006/11/sansho-pepper/
 Proverb — sanshoo wa kotsubu demo piririto.
 Matsumoto – http://catalogue.nla.gov.au/Record/2311588
 Nihon University – http://www.http://idmmei.isme.org/index.php/institutions?pid=86&sid=2948
 Ochanomizu Women’s University Research Institute — http://idmmei.isme.org/index.php/institutions?pid=86&sid=2948:Ochanomizu-University-ochanomizu-Joshi-Daigaku
l7] Fuchsia Dunlop, ma la -- http://www.tinyurbankitchen.com/2009/12/mala-spicy-and-numbing-broth-for.html