Plant of the month (©Pierre Laszlo, all rights reserved)
Capsicum genus (Solanaceae).
The ubiquitous French dish, salade niçoise, could not have existed prior to Columbus: it includes tomatoes, potatoes and green peppers, in addition to hard boiled eggs, olives and anchovies, together with an olive oil dressing. The first three were unknown outside of the Americas prior to 1492. The Spanish conquistadors brought them back and they spread all over the world.
This piece focuses on the bell pepper ingredient in a niçoise and indeed on the timing of various events in its long association with mankind. Thus, let me first mention molecular clocks. By counting mutations in, e.g., a protein molecule, biochemists are able to date their sequential occurrence. Detailed comparison of genomes is also useful.
Peppers and tomatoes are close relatives. They diverged about 36 million years ago, during the Eocene period. Their family, of which potatoes and nightshades are also members, the Solanaceae, appeared nearly 156 million years ago, soon after differentiation of monocotyledonic and dicotyledonic plants.
The genus has at least 32 species native to the tropical Central and South Americas. Quite a few such species cross fertilize into hybrids. Amerindians domesticated several such species at least 6,000 years ago. Domestication was achieved by different groups in different locations. It was, arguably, the first spice domesticated by humans.
Domestication brought about, among its consequences, fruit gigantism, a change of shape (the wild fruit is small and round), colors other than red, continued attachment to the peduncle at maturity, and variability in the levels of capsaicin — the alkaloid responsible for the pungent ‟heat‟ of chili peppers, that excites strong perception by the trigeminate nerve apparatus in the nose and mouth.
Peppers have been eaten for at least 9,000 years. Domestication did not occur until several millennia later. Archeologists found in northeastern Mexico evidence of Capsicum annuum, in Romero Cave in the Mexican state of Tamaulipas and in Coxcatlán Cave, farther south, in the state of Puebla, both estimated to be around 7,000 to 9,000 years old based on contextual evidence. Four other species of Capsicum originated in South America and may have been domesticated much earlier than their Mesoamerican cousin. Starch grains which preserve well and are characteristic of the species they originate from have allowed scientists to peg domestication of chili peppers to at least 6,100 years ago, in southwestern Ecuador at the sites of Loma Alta and Loma Real. Peru’s Huaca Prieta is an ancient site on the Pacific coast where archaeologists found traces of all four of South America’s native chili peppers. These plants may have been domesticated elsewhere on the continent — in the Andes and eastern Amazon — but appear to have been brought to Huaca Prieta more than 7,000 years ago. Peppers were cooked many centuries before the Christian Era, there are traces on pottery remnants excavated by archeologists, in Mexico for instance.
The highly diverse uses of peppers included, in addition to food, drinks and spices, dyes, medicine and poisons, weapons, preservatives, insecticides and pesticides. Not to mention derived products, such as the present spicy commercial items — Tabasco sauce and paprika, among many others — and capsaicin-containing creams.
The Hungarian biochemist Albert Szent-Gyorgyi, wanting to isolate this then elusive health factor, thought of green peppers and with an abundant crop in his country as a source: discovered vitamin C, earning him a Nobel Prize.
Capsaicin is the chemical responsible for the hot taste of red chili peppers. It belongs to the family of vanilloids, molecules with a vanillyl-based structure. Its mode of action is well identified. It interacts in the nose and the mouth with the heat-sensitive, non selective, ion channel TRP V1. Neurons in these body parts detect noxious heat, above 43 °C. They do so via ionic channels, that let ions such as sodium ,potassium or calcium cross the cell membrane. Capsaicin binds to TRP V1 in an intracellular region. Capsaicin thus induces a hot sensation, an alert signal.
Otherwise, capsaicin is a molecule which some view as a cure-all, others consider as dangerous. It has been well documented as preventing fat accumulation, lowering blood pressure, but it is also both a carcinogen and a killer of tumor cells — inducing them to commit suicide (scientifically known as apoptosis). In topical use on the skin, capsaicin-containing creams relieve pain — but they may also induce skin cancer.
Finally, I’d like to elaborate on my all-too-brief mention of paprika, with this personal note. Since I am of Hungarian descent, peppers are to me an ethnic food, i.e., a taste from nurture instead of later acquired. I am fond of peppers, both in the raw, slices sprinkled with salt, and cooked, stuffed with rice and ground meats, and seasoned with a tomato sauce — a dish associating these two fruits that had split in the Eocene.
I have a suspicion that Turkish invaders, who occupied Hungary for a century and a half, introduced Hungarians to growing and eating peppers — stuffed peppers are thus a Turkish legacy. I have another childhood recollection linking my Hungarian parents with peppers, any picnic or camping trip would include a container to keep butter cool and prevent its melting, in the form of an hollowed out pepper. However, my Hungarian heritage has quite a flaw. My body is intolerant of paprika in hefty doses as delivered by the national dish, the stew known as gulasch!