Bean Biodiversity
As our forbearers began to move away from being hunter-gatherers to more sedentary farmers, one of the principle issues that they needed to address was balancing their protein intake from vegetable materials. While meat provides all of the essential amino acid building blocks needed for a healthy body, a given plant material in general does not provide complete protein. Rather it is necessary to eat a variety of vegetables to ensure that all of the needed amino acids are present in the diet. What our ancestors learned -- and what vegetarians today recognize as one of the basic tenants of a healthy diet -- is that complete protein is usually present when you eat grass grains and legume seeds in the same meal.
Over and over again across the globe, different civilizations discovered this fact, and early on domesticated different legumes out of their local environment. Because this domestication extends back to the dawn of civilization, it should not be surprising that the words associated with these crops are also of long use. For instance, by linguistic comparison of the various words for ‘bean’ suggest it originated from the Proto-Indo-European noun for ‘woman’. This root was then applied to any large edible legume seed, and eventually morphed into bean (English), boon (Dutch), Bohne (German), bønne (Danish), baun (Icelandic), ben (Irish), bein (Scottish), bob (Russian), phasóli (Greek), faba (Latin), or lobi (Armenian). Smaller legumes were eventually given other names, with intermediate-sized seeds generally being called ‘peas’ (from the Greek “pison” and Latin “pisum”) and the smallest being called ‘lentils’ (from the Greek “lathyros”, Latin “lenticula”, and Old German “linse”).
The ancient history of these words means that as new crops appeared in a given area through trade, pre-existing names were often used to describe these new crops, even though they were not closely related to the initial named plants. As a result, the words “bean”, “pea”, and “lentil” now represent a hodgepodge of little biological value.
One easy way to navigate these rough biological and linguistic shoals is to consider these various legumes through their history. The earliest legumes were domesticated in the Fertile Crescent and Middle East from wild ancestors living in rocky grasslands and riversides, and include:
- Lens culinaris (Lentil) may be the first domesticated legume extending back to at least 9500 years ago, and possibly into the late Ice Age. It spread east into India, where it is called Masoor Dal and is one of the principle pulses used in cooking. It also spread west into the Mediterranean basin, and ultimately throughout the world.
- Vivia faba (Broad Bean /Fava Bean) was perhaps domesticated as early as 9000 years ago. Like peas, Broad Beans are able to mature in short, cool summers and thus became a principle crop for northern cultures. This species has a tough, indigestible seed coat that must be removed prior to eating. The use of ‘bean’ in any pre-Columbian old world text is referencing this plant, not the Common Bean of the New World.
- Cicer arietinum (Chickpea or Garbanzo) was domesticated around 7500 years ago. This crop spread east into India (where it became one of the major pulse crops) and west into North Africa and western Eurasia, and then around the globe. There are two major forms: the large, pale seeded Kabuli, which is the most typically seen form in the west; and the small, brown Desi which has a much tougher seed coat. In India their seeds are hulled and split to make Chana Dal.
- Pisum sativum (Pea) was also first domesticated around 7500 years ago. For most of human history, ‘peas’ referred to dry, starchy soup peas. These became a staple crop of northern countries that did not have long and hot enough summers to allow harvest of Chickpeas, Lentils and Broad Beans. It was not until the Renaissance that sweet, non-starchy green peas for fresh consumption were bred.
The legumes domesticated in Asia include:
- Vigna angularis (Azuki Bean) was domesticated in Japan around 6000 years ago from wild ancestors living along rivers. This small red bean is usually cooked into a sweetened paste which is then used as a filling in deserts.
- Vigna radiata (Mung Bean or Green Gram) was domesticated in the Mongolian steppes and spread into India by 4500 years ago. From there it was traded across southeastern Asia. The small beans are not only cooked, being one of the principle pulses used in dals, but also sprouted in many southeastern Asian cuisines.
- Vigna mungo (Urad or Black Gram) was domesticated in about 4500 years ago from wild plants living in the savannas of southern India. It is largely used whole or split to make dal, where it adds a slimy texture, and is ground to make dosas, idlis, and papadums.
- Cajanus cajan (Pigeon Pea) was domesticated about 3500 years ago from wild plants living in the dry tropical forest of eastern India. It spread from India into eastern and then western tropical Africa, and then via the slave trade to the Caribbean. In India it is referred as Toor Dal, and is one of the most popular pulses. It makes up the ‘peas’ in the famous ‘peas and rice’ of Jamaica.
- Glycine max (Soybean) was domesticated in eastern northern China only 3100 years ago. It has since become the principle source of vegetable protein throughout eastern Asia. However, in its raw state the proteins are not easily digestible. Soy-based Asian cuisines have found a number of methods to make soy easier on the digestive system, including the making of soy milk, tofu, and fermented soy products such as miso and tempeh. Some varieties have also been bred for their immature, green seeds, known in Japan as edamame.
The one major legume domesticated in Africa was:
- Vigna unguiculata (Cow Pea / Crowder Pea / Field Pea) which was bred about 5000 years ago from wild plants living in west African savannas. From there it spread across the dry-tropics of central Africa and then to India and southeast Asia. During the slave trade it was also transported to the New World, where it became an important crop in the plantations of the southern USA, Caribbean, central America, and northern South America. Cow Peas are among the most drought and heat-tolerant legumes, and are able to produce high yields in even poor soils. Not only are the dried beans used in cooking, but so are the unripe green pods which are used extensively as ‘yard-long beans’ in southeast Asia.
Four major legume crops were domesticated in the New World, and were unknown in Europe and Asia until after the voyages of Columbus:
- Phaseolus vulgaris (Common Bean) was domesticated around 4500 years ago in central America and the Andes from wild plants of the lowland dry tropics. It was quickly adapted by Old World cultures as it was easier to grow, more productive, and easier to cook than Broad Beans. It is now an essential component of cuisines ranging from India across the Middle East into the Mediterranean Basin and northwestern Europe. Of course, common bean pods are also picked immature as a green vegetable. Confusingly, the entire pod is usually referred to as a green ‘bean’, although technically the word ‘bean’ should be limited to only the seeds inside the pod.
- Phaseolus lunatus (Lima Beans) was domesticated about 4000 years ago in the northern Andes, and independently 1200 years ago in Mexico from wild lowland dry topics plants. They are used much like Common Beans, but the freshly shucked seeds (often referred to as ‘Butter Beans’ in the southern USA) are also often cooked alone or with other vegetables in stews.
- Phaseolus acutifolius (Tepary Bean) was domesticated in the deserts of northern Mexico about 3500 years. It is one of the most drought-tolerant crop plants. These small beans are cooked in the same way as dry common beans.
- Phaseolus coccineus (Runner Bean) represents the most recent legume domestication, having been selected from wild ancestors in the Mexican Highlands only 1000 years ago. It has since spread across the globe, and is an important component of both Greek and Iraqi cuisine. This crop is grown not only for its large dry seeds, but also immature pods which can serve as a green bean. The starchy roots may also be eaten.
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