On Capsaicin

In my recent post on conceptual cooking, I wrote for a little bit about spicy food. My brother gave me a bottle of crazy hot sauce to play around with for a birthday present, so in honor of that I thought it would be fun to write a bit about hot hot foods in general.

Image: cjansuebsri / FreeDigitalPhotos.net

First, some science stuff. As I stated before, there are a bunch of different receptors on the tongue. Some of these are pain receptors, of which there are a few different types. The hot part of chili peppers binds to a specific receptor called vanilla receptor subtype 1 (VRC1 or TRPV1). Normally, the VRC1 receptor responds to heat and abrasion. This is why we perceive spicy food as being "hot" - our brains integrate the actions of this channel into thinking that we are actually being burned. As a result, we start going through inflammatory responses to cool the affected down. These can vary from localized redness and swelling if you rub a pepper on your skin to full-body sweating and ruddiness if you eat a ton of hot food. These receptors are found all over the body, which is why you should avoid touching your eyes when cooking with peppers. Different people have different concentrations of these receptors, which is why some people are so much more tolerant of spicy food than others. They aren't tough, they simply cannot have a physiological response without more hot stuff.

Note that VRC1 isn't made to respond to plant oils - chili peppers have just evolved to exploit this particular receptor. This is probably because when mammals eat peppers, they tend to grind the seeds into oblivion with their molars. This is clearly not good for the chili pepper.

The molecule famous for making chili peppers hot is called capsaicin. However, it is but one of six naturally occurring and structurally similar molecules to have this effect. Collectively, these molecules are known as capsaicinoids. Each produces a slightly different sensation. Capsaicin and the extremely similar dihydrocapsaicin  produce the strongest, fastest burns. Different concentrations of the six molecules can lead to different durations and perceptions of the burn. This is why some foods seem to take a while for the heat to kick in - there can literally be a different set of molecules responsible for the burn. Spiciness is measured in Scoville Heat Units (SHUs). Bell peppers can get to be a few hundred SHUs, jalapeños 5000, habañeros 200,000. The pepper in my new hot sauce, the Bhut Jolokia or Ghost Pepper, is upwards of 1,000,000 SHUs. That's in the same range as commercial pepper sprays used in self-defense.

Capsaicinoids aren't the only molecules that cause a burn. Hot mustards, horseradish, and wasabi instead use allyl isothiocyanate and a few related compounds. These stimulate both the VRC1 receptor and a related receptor that is supposed to respond to a number of negative stimuli. It didn't surprise me to learn that a different compound gives these foods their pungency - I've loved spicy foods since I was a little kid, but I can't stand horseradish and mustard.

Unfortunately for all these plants, some humans have grown to enjoy a bit of heat. The exact reason for this isn't known, but some chiliheads claim that the pain stimulates the release of endorphins. It's also possible that (as I mentioned in the other article) it helps to form a more rounded flavor profile. Whatever the reason, spicy foods have made their way into cuisines around the world.

A few interesting side notes:

• Counterintuitively, capsaicinoids can be used as topical analgesics (pain relievers). They overload the VCR1 pain receptors and block out further transmission of pain.
• Capsaicinoids seem to have antifungal and limited antibiotic properties. Hooray!
• Though many people think spicy foods can cause or exacerbate ulcers, there is little in terms of hard evidence to support this. A huge majority of gastrointestinal ulcers are bacterial in origin.
• Birds are unaffected  by capsaicin. Looking to keep squirrels out of your bird feeder? Toss some hot pepper seeds into the mix (birds also don't have molars to grind up pepper seeds if they eat them - coincidence? Doubtful).

Edit: After hunting around on the internet, it seems that the hot sauce my brother bought me is 650,000 SHUs. Tabasco and Frank's Red Hot are around 2,000. I put a drop in a bowl of soup and, well, it was really hot. The reviews on amazon are fantastic (Dave's Ghost Pepper Naga Jalokia Hot Sauce, 5 oz). I'm about to try some on a chip - hopefully I won't die.

Double edit: After dousing a saltine in hot sauce (I didn't want to open a bag of tortilla chips) I am filled with nothing but regret.