I love chile peppers and spicy food. I grow up to a dozen varieties of chile peppers each year, and turn the fruits into sauces, spreads, and salsas. For me, nothing tastes better than fresh homemade salsa, a few dashes of my Tabasco-style sauce, or fresh Thai chiles in my Pad Kra Pao. And I’m not alone. In the United States salsa is often the number one condiment sold, flip-flopping with ketchup or mayonnaise. Throw in Tabasco and the thousands of other hot sauces, and chile peppers dominate the market. But to really understand chile peppers, and their cultural significance and chemistry, we need to go back in time more than 500 years. Hold on.

Some sort of Capsicum frutescens hybrid via cross-pollination. Chiles and photo by Justin Brower.

As mind-blowing as it may sound, chile peppers aren’t native to Europe, Africa or even Asia, the lands of the so-called “Old World.” It wasn’t until the voyage to the “New World” Americas by Christoper Columbus in 1492 that the rest of the world would enjoy the pungent fruit. The term “Columbian Exchange” refers to the exchange of crops, diseases and ideas between the Old and New worlds. The exchange permanently changed the landscape of agricultural foods in the Old World. Important staple crops such as corn, potatoes and cassava provided calorie rich foods that were a nutritional improvement over wheat. With regards to the impact of the potato on Ireland, not only did the lowly spud spur population growth, but may have led to urbanization (1).

Other crops like tomatoes, cocoa, and chiles, may not have been as calorie-dense, but they provided important vitamins and minerals, as well as improved the taste of food. As quickly as 1493 chiles made their way to Spain, and by 1542 arrived in India. From India the chile peppers migrated east into China and southeast Asia, where they quickly took hold.***

*** Some speculate that chile peppers could have arrived in Asia pre-Columbian Exchange via Pacific Ocean routes. Is it possible? Sure, why not. Maybe I’ll write about that another day, but for now, I’ll just go along with the majority of historians.

It’s incredible to me that foods I associate with a particular country or region are relatively new, and have only been a part of their everyday gastronomical experiences and cultures for 400 or so years. When I think of Hungary, I think of paprika, the dried and ground powder of pimento chiles. China? The bold and spicy flavors of Sichuan cuisine heavily dependent upon chile peppers. Thailand? Chile peppers galore, which is probably why my family and I cook and eat Thai food so much. The general appeal and widespread use of chile peppers owes to its genetic diversity. There really is a chile pepper for everyone!

Chile peppers belong to the genus Capsicum, of which there are five cultivated and “domesticated” species:

• Capsicum annuum: The bell peppers and jalapenos. Most “supermarket” peppers.
• Capsicum frutescens: Tabasco and Thai peppers. Typically grow upright.
• Capsicum chinense: Habanero and Scotch Bonnet varieties, as well as the “super hots”
• Capsicum baccatum: Aji and “Hot Lemon” varieties.
• Capsicum pubescens: Includes Rocoto peppers. Not common.

In addition there are about twenty “wild” species that are not heavily commercialized, if at all. Despite the species “annum” name, chiles are not annuals at all. They are perennials and can live for decades given the right environment. In California I had several Tabasco plants that lived for years. Sadly, they didn’t survive the move to Charleston, SC.  Being a perennial also gives the chile plant a head start in reproduction, as it doesn’t need to exert time or energy in growth, and can start right in on producing fruit. And make no mistake, chiles are fruits, and the goal is to produce and distribute its genetic code – the seeds.

A common way for chiles to spread and grow in the wild is birds. Yes, birds. Our avian friends eat chiles, fly miles away, then bombard the earth with a mixture of chile seeds and “fertilizer”…bird poop, if you didn’t clue in on that. It just so happens that birds, through a genetic mutation (compared to mammals), are insensitive to the heat and burn of chile peppers, which is evolutionary genius if you ask me. Or divine planning. Your call.

So now we get to the good part. What exactly makes chile peppers so hot? It’s a family of chemicals called capsaicinoids, with capsaicin being both predominate and the most pungent. Chiles produce capsaicin as a defense mechanism against mammals, which most everyone has experienced at some point – it’s hot and burns, in your mouth, on your skin, and in your eyes. Outside of culinary uses, it’s nasty, which is probably why “pepper sprays” exist. But capsaicin is also a defense against fungus, with capsaicin inhibiting the growth of many types of fungus (2).

Capsaicin

The heat and “burn” from capsaicin is really just a painful stimuli mediated by TRPV ion channels. TRPV stands for Transient Receptor Potential Vanilloid. Seriously. I know it sounds funny, but you just gotta trust me on this one. We’ve talked about ion-channels before with aconitine and saxitoxin, but TRPV1, the ion-channel sensitive to capsaicin, is a bit different. TRPV1 is non-selective, and is activated by high temperature, capsaicin, and allyl isothiocyanate, the noxious chemical explained in the horseradish post. (see reference 3 for a review article on TRPVs)

Jalapenos by Justin Brower

TRPV1 is located throughout the body, and in varying amounts person-to-person, and is associated in many pain mechanisms. What is most intriguing, is that when activated, TRPV1 activity decreases, in what is called desentitzation (4). We experience this all the time when we eat something hot. The first few bites may be painful, but then we relax and wipe the sweat off our brow, and then a few minutes later the subsequent bites aren’t as bad. Still hot, but not as painful as the first ones.

The pharmaceutical industry is big on TRPV1 right now, and for good reason. There are two approaches. One is to activate the TRPV1 channels so that desensitization occurs, thus you’d feel less pain. We see this at the pharmacy with those capsaicin creams for arthritis. You feel a bit of pain or burn from the capsaicin, and then less pain from the arthritis. The second approach is to generate a TRPV1 antagonist, something that blocks the channel and keeps it from being activated in the first place. Development has been hampered by hyperthermia, an increase in body temperature, but it is still an interesting therapeutic target.

Getting back to chiles, peppers have various amounts of capsaicin in them, and elicit varying degress of pain. The “hotness” of peppers is rated on the Scoville Scale, devised by American pharmacist Wilbur Scoville – the higher the number the more blstering the heat. It’s basically determined by how dilute you can make a chile pepper extract and still detect heat. You already know the flaw in this, it was in the previous paragraph: TRPV1 variability and desensitization. A more precise method is using modern analytical instruments, such as HPLC or LC/MS to quantitate capsaicin, and then scaled so that it somewhat matches the human derived Scoville unit (to avoid confusion and a new scale).

Scoville units range from:
0 Bell peppers
~2000 Jalapenos
~200,000 Habaneros
~2,000,000 Bhut Jolokia, Trinidad Scorpion, and Carolina Reaper peppers.

Harvesting the chiles by Justin Brower

Obviously the super-hot peppers are just plain dumb – just kidding . . . kind of. I like hot foods and peppers, but pure pain is not my idea of a good time. Chile peppers all have their own unique flavor. For instance, habaneros are actually fruity, and make for a wonderful addition to jams and jellies. But the Bhut Jolokia? I’m not sure you’d be able to get to the point of being able to enjoy its flavor. Regardless, developing and growing the hottest chile pepper is something that people compete at. Besides, it keeps them off the streets, for which we should all be thankful, and the only perople they are hurting is themselves.

So there you have it, a bit of a primer on chile peppers and capsaicin. People write books on this, and I aim for a thousand words, so I’m sure I’ll write more on it at a later date. The one thing I didn’t mention is that chiles are easy to grow. They are practically maintenance free, don’t have a lot of pests, and can be grown for their ornamental properties, not just culinary. You can even save the seeds (I do) and grown them next year – though cross-pollination can be a problem – so it’s a great and easy way to teach youngsters how to save seeds and grow food. You are not only preserving your fiery foods, but preserving history and culture.

References:
1. Nunn, Nathan, and Nancy Qian. “The Columbian Exchange: A History of Disease, Food, and Ideas.” Journal of Economic Perspectives 24.2 (2010): 163-88. [Free PDF]
2. Veloso, J., C. Prego, M. M. Varela, R. Carballeira, A. Bernal, F. Merino, and J. Díaz. “Properties of Capsaicinoids for the Control of Fungi and Oomycetes Pathogenic to Pepper.” Ed. H. Papen. Plant Biology 16.1 (2014): 177-85.
3. Ramsey, I. Scott, Markus Delling, and David E. Clapham. “An Introduction To Trp Channels.” Annual Review of Physiology 68.1 (2006): 619-47. [Free PDF]
4. Green, Barry G. “Capsaicin Sensitization and Desensitization on the Tongue Produced by Brief Exposures to a Low Concentration.” Neuroscience Letters 107.1-3 (1989): 173-78.
5. Moran, Magdalene M., Michael Allen Mcalexander, Tamás Bíró, and Arpad Szallasi. “Transient Receptor Potential Channels as Therapeutic Targets.” Nature Reviews Drug Discovery 10.8 (2011): 601-20. [Free PDF]