Legumes

David S. Seigler Department of Plant Biology University of Illinois Urbana, Illinois USA

Legumes - Outline Importance: all cultures - ancient - e.g., lentils fix nitrogen Botanical Fabaceae fruit a legume or pod Properties physical nutritional protein: must be detoxified steps in domestication, indehiscent pods

Major legumes Near East: lentils garbanzos broad beans peas New World: Phaseolus spp. peanuts

China: soybeans (Glycine max) Vigna spp. Africa: Vigna unguiculata pigeon peas

Reading Chapter 6 - Legumes seeds of members of the Fabaceae p

Introduction Second only to the grasses in their importance to humans and our domestic animals. Every major civilization has been based on a legume as well as a cereal grain. Legumes are by definition all members of the Fabaceae or Leguminosae. This is a large family with perhaps 18,000 species.

Courtesy Dr. Ted Hymowitz

The legume The Fabaceae consists of three subfamilies. Almost all important crop legumes are in the subfamily Faboideae (Papilionoideae). Fruit a legume. Commonly known as "pods". A single carpel that splits along two longitudinal margins at maturity to release its seeds.

Many important legumes in table on page 143. Diagram of legume flowers and fruits p World production... see page 144.

Nitrogen fixation The roots of most legumes form associations with bacteria that can fix atmospheric nitrogen. These Rhizobium species live in nodules on the roots. They provide “free” fertilizer. Flowering plants cannot use atmospheric nitrogen but must absorb nitrate or ammonium nitrogen through the roots. Nitrogen cycle on pg. 140.

Nodules on Lupinus texensis roots

Nutritional value Legumes rich in protein (nitrogen). See table on pg. 142 for nutritional composition. Many are in the 20-30% range. Legumes also contain some fats but usually less starches than cereal grains.

Nutritional value Amino acid composition different from that of cereal grains. Legume seeds have more of some amino acids than cereal grains. Seeds of almost all legumes are toxic if eaten uncooked because of proteins or peptides that inhibit digestive enzymes.

Important points Legumes fix nitrogen Legumes rich in protein Legumes easily stored and harvested

Ancient cultivars Near East and Europe: peas, broad beans, lentils, and garbanzos. New World: common beans, lima beans, and peanuts South East Asia and China: soy beans, mung beans (Vigna aureus) and adjuki bean (Vigna mungo). Africa: black-eyed pea, pigeon pea.

Domestication of legumes Lentils are one of oldest domesticated legumes Wild small-seeded legumes used. By 6000 B.C., lentils, peas, vetch (Vicia sp.), bitter vetch (Vicia ervilia), and garbanzos were already cultivated. In Africa Vigna by 2000 B.C. In the Americas, Phaseolus coccineus in Tamps. by 5000 B.C. wild harvested.

By 4000 B.C., P. vulgaris and P. lunatus were cultivated in Peru. Many domesticated legumes have lost the ability to reseed themselves. Pods of cultivars are indehiscent.

Lentils (Lens culinaris) Among the most ancient of cultivated crops years in the Near East. Lentils found in archaeological sites before that, but as is the case for cereal grains, it is difficult to sort out what is cultivated and what is not.

Lentils (Lens culinaris) Lentils especially high in protein. Lentils drought resistant. By 2200 B.C., they appear in Egyptian tombs.

Lentils, Lens culinaris

Lentils particularly important in India today. Many different kinds of "dhal". In the U.S. mostly cultivated in Washington and Idaho in the Palouse Prairies.

Peas (Pisum sativum) Peas are also an extremely old crop from the Near Eastern center. Peas go back at least 9000 years. They may have also come from Ethiopia and Central Asia.

Peas (Pisum sativum) In the Middle Ages in Europe, dried peas made up a major part of the diet of peasants. Still very important there, especially in Eastern Europe. People didn't eat "green peas" until about the 1700's. Peas are the fourth most important legume crop world wide.

Peas, Pisum sativum and Garbanzos, Cicer arietinum The Complete Book of Fruits & Vegetables, F. Bianchini, F. Corbetta, M. Pistola, Crown Publishers, New York, 1973

Pea fields in Washington

Broad beans (Vicia faba) Broad beans domesticated in the Near Eastern Center. Cultivation of these beans goes back to Egyptians, Romans, and Greeks. The only common bean in Europe before Production spread to Asia at some time in the past and today China is the world's largest producer of broad beans.

Broad beans (Vicia faba) The Spanish brought broad beans (habas) to the New World. Grow best in a cool climate. Canada produces more than the U.S. Cause a genetic disorder "favism" in some people that eat them.

Broad beans, Vicia faba

Garbanzos or chick peas, Cicer arietinum Also from Near Eastern Center (Northeast Africa). Cultivated 7400 years ago. By 2000 B.C. introduced into India. India now grows 79% of world's crop. Brought to the New World by the Spanish and Portuguese.

Garbanzos, Cicer arietinum, Fabaceae

Soybeans (Glycine max) Soybeans arose in China. Cultivated at least 7000 years ago. In Chinese literature before 1000 B.C.

Soybeans (Glycine max) About 38% protein and 18% fats and oils. The amino acid content is especially good. Serve as a source of edible oils. In the Orient, soybeans are eaten in many different ways. Converted to miso, tofu, okara, soy milk, soy sauce, curd, cheeses, and greens (sprouts).

Glycine max, soybean, in flower

soybeans

Soybean harvest

Variation in soybeans National Geographic

Although soybeans were introduced to Europe quite early, they never became popular. In Pennsylvania by Benjamin Franklin was sent a sample of seeds and both he and Thomas Jefferson grew them. Until 1940's never common in the United States.

Coagulated soy protein called tofu. Most of the U.S. soybean crop is consumed indirectly. Over half of our production is exported. Much is used in this country as "texturized vegetable protein". About 15% of crop used for industrial purposes. Soy beans are the most important bean crop in the world.

Pigeon peas (Cajanus cajan) Pigeon peas (gandules) commonly cultivated in the Caribbean area. Native to Africa and introduced into New World by black slaves. Cultivated perhaps 4000 years in Africa. Widely cultivated in India, which grows 95% of the world's crop. Pigeon peas do well on poor soils.

Pigeon peas, Cajanus cajan

Black-eyed peas, Vigna unguiculata Black-eyed peas also domesticated in Africa and brought to the Americas by black slaves. Other species of the genus are widely cultivated in Asia. These or related species were in India by "Sanskrit times". Romans and Greeks knew them. In the U.S., mostly grown in Texas, Georgia, Oklahoma, and the Carolinas

Asian Vigna species Many species of Vigna were domesticated and cultivated in Asia. Black gram or urd bean (Vigna mungo). Mung bean (V. aureus) Adjuki bean (V. angularis) (and others). Usually included in "bean" statistics.

Adjuki bean, Phaseolus mungo

Lima bean, Phaseolus lunatus Lima beans may have been independently domesticated in Mexico and in northern South America. Appear to have spread southward into other parts of South America. The oldest cultivated materials are from Peru ( years old).

Lima bean, Phaseolus lunatus In 1492, cultivated from Canada to Argentina. Usually perennials in the tropics. Many lima beans are highly toxic unless prepared properly. This is not true in the United States and Europe, however.

Primitive lima beans

Lima beans from San Juan, Puerto Rico

Scarlet runner bean, Phaseolus coccineus The scarlet runner bean (Phaseolus coccineus) is an ancient cultivar in Mexico. They are still commonly eaten there. This species also a common bean in Europe.

Scarlet runner bean, Phaseolus coccineus

Common beans, Phaseolus vulgaris Kidney beans, pinto beans, navy beans, black beans, green beans, wax beans, and snap beans are all Phaseolus vulgaris. Domesticated in Mexico and South America. Domesticated several times. Fossil cultivated beans go back 7000 years in Mexico and almost as far in Peru.

Navy beans, Phaseolus vulgaris

Kidney beans

Beans were commonly cultivated in all parts of the Americas in This species is the second or third most important bean crop in the world. The American Indians commonly cultivated beans with squash and corn. This was partly to provide support for the beans which were viny, but had dietary implications as well.

Peanut or groundnut (Arachis hypogaea) Peanuts native to central South America. Domesticated by the Guaraní Indians. By 2000 B.C. cultivated in Peru. Portuguese took peanuts to several parts of the world in the early 1500's. Now hard to tell that they are not native. They were widely cultivated in Africa. Brought back to the Americas by black slaves.

Arachis hypogaea, peanut in flower

Arachis hypogaea, peanut fruits

Peanuts important in the southeastern U.S. in sandy soils. Largely replaced cotton in the South after the boll weevil became a major pest about Peanuts are widely eaten in West Africa and Asia today. Peanuts are the second most important legume, but are often not eaten directly.

Contains more oil than most legumes. Peanut oil widely used in West Africa and France. Usually used to fondue because of its higher temperature properties. Fruits borne under the ground. Much U.S. production goes into peanut butter. Aflatoxin is a major problem.

Vigna (Voandzeia) subterranea, bambara groundnut

Tamarind and Carob Tamarinds (Tamarindus indica) have been used in tropical Africa and Asia for thousands of years. The sticky pulp surrounding the seeds has a sour taste and is the part used. Used in many types of sauces. See pg. 152.

Tamarindus indica, tamarind Bentley and Trimen, Medicinal Plants

Carob (Ceratonia siliqua) has also been cultivated in the Near East for thousands of years. Fruits have long been used to feed livestock. Carob currently used as a chocolate substitute and as a source of "locust gum".

Ceratonia siliqua, carob Courtesy Dr. Ben-Erik van Wyk