14 Crops – LegumesGeorge

Legumes belong to the family Leguminosae and consist of oilseeds such as soybeans, peanuts, alfafa, clover, mesquite, and pulses, including the dry grains of peas, chickpeas, lentils, peas, beans, and lupins. Production and use of legumes date back to ancient cultures in Asia, the Middle East, South America, and North Africa. They are cultivated throughout the world for their seeds, harvested and marketed as primary products. Grain legumes are grouped into pulses and oilseeds. The pulses are different from the leguminous oilseeds, which are primarily utilized for oil (Schneider, 2002). There are about 1300 species of legumes, with only about 20 commonly consumed by humans (Reyes-Moreno & Paredes-Lopez, 1993). Notable amongst legume species are chickpeas (Cicer arietinum), pigeon pea (Cajanus cajan), lentil (Lens culinaris), mung bean (Vigna radiata), soybean (Glycine max), winged bean (Psophocarpus tetragonoloba), cowpea (Vigna unguiculata), pea (Pisum sativum), groundnut (Arachis hypogaea), and black gram (Vigna mungo), to mention but a few. Some of the most important legumes in the world are peas, beans, peanuts, soybeans, and chickpeas (Reyes-Moreno et al., 2000). Canada is the leading producer of peas in the world, with about 3,379,400 metric tonnes (MT) produced in 2009 (FAO, 2009). In 2010, the US was the leading global producer of soybeans and the second and third top producer of peas and lentils, respectively (Table 14.1). In the same year, the US was also the fourth leading producer of dry beans and peanuts. Canada again tops the production of lentils and is the seventh and ninth leading producer of soybeans and chickpeas. Similarly, production of dry beans and chickpeas in Mexico is high and the country ranks fifth and eighth in global production, respectively. Brazil was the leading producer of dry beans in 2009. The leading producer of chickpeas in 2009 was India with 7,060,000MT. Cutting-edge research in plant breeding and agronomic practices in the last several decades has allowed suitable varieties and cultivars for the North American climate to be identified, which has resulted in marked increases in legume production in the region. Although a large percentage of the legumes produced in North America are exported, there is growing interest in expanding domestic consumption, due to increased awareness of their health benefits. Legumes have a special place in the diet of humans, because they contain nearly 2–3 times more protein than cereals (Reyes-Moreno & Paredes-Lopez, 1993). Cowpeas, for example, contain about 25% protein (Annor et al., 2010). Legumes are also excellent sources of complex carbohydrates and have been reported as beneficial for cardiovascular diseases and diabetes by some researchers (Hu, 2003; Jacobs & Gallaher, 2004), probably due to the large amounts of water-soluble fiber and a large content of phenolics (Enujiugha, 2010). Legumes are also a good source of vitamins (thiamine, riboflavin, niacin, vitamin B6, and folic acid) and certain minerals (Ca, Fe, Cu, Zn, P, K, and Mg), and are an excellent source of polyunsaturated fatty acids (linoleic and linolenic acids) (Augustin et al., 1989). Indeed, several studies suggest that increased consumption of legumes may provide protection against diseases such as cancer, diabetes, osteoporosis, and cardiovascular diseases, among others (Hu, 2003; Pihlanto & Korhonen, 2003; Tharanathan & Mahadevamma, 2003). Legumes further offer a practical avenue for diet diversification as consumers look for greater balance between plant and animal food sources. With growing concerns about the impact of agricultural practices on the environment,