It's been almost three years since I brought a bag of Sichuan peppercorns into the office, and doled them out to an unsuspecting editorial staff. As everyone let the papery husks sit on their tongue they experienced a citrusy electric sensation -- almost a buzzing. "That's disturbing," said one writer, likely because Sichuan peppercorns produce touch perceptions as much as they do taste. It's very unique.
We've known for a long time that compounds called sanshools present in the peppercorns cause the numbing, tingling sensation that electrify the mouth. What's been unknown until recently is how those sanshools work, and NPR has a story about the scientist who discovered just that.
Diana Bautista, a neuroscientist at the University of California, Berkeley, wondered if the numbing and tingling sensation could somehow related to the prickly feeling we experience when our foot falls asleep. To find out, she exposed mouse neurons responsible for touch, itch and pain to sanshool, and only the big ones responsible for touch and vibration reacted demonstrating Sichuan peppercorns actually stimulate touch receptors. Bautista is hoping to use what she's learned to treat patients that have chronic tingling sensations in their limbs.
Another researcher used test subjects and boxes that vibrate at variable rates to determine what frequency we perceive when stimulated by the peppercorns. It's 50 hertz, which is about an A flat if you've got your accordion handy.
If you want to make your own mouth music head to Royal Sichuan in Richardson. I think they have one of the most electric versions in Dallas of Mapo tofu, what is likely the most popular Chinese dish to feature Sichuan peppercorns. Tell them you want a little extra spice and get ready. Your mouth will be buzzing like a kazoo.