Bean is a common name applied to large seeds of several genera of family Fabaceae used for human as well as animal consumption. The green, young pods of bean plants are often consumed as raw or cooked. They are known as green beans when unripe. The term bean is generally used for the broad bean but later on it was expanded to include members belonging to the genus Phaseolus as well as Vigna. The term is now applied to many other plants also for example soybeans, peas, lentils, chickpeas (garbanzos), vetches, and lupins.
Beans are one of the oldest plants known in cultivation since times immemorial. Broad beans were earlier cultivated in Afghanistan and Himalayan foothills. Common bean is known in cultivation for about six thousand years in America. About 4,000 cultivated varieties are known from America alone. The common varieties of bean include broad bean, moth bean, urad bean, mung bean, rice bean and cowpea. Some varieties of bean especially the red and kidney beans contain a toxin that must be destroyed before cooking.
The recommended method adopted for these beans is to boil them for ten minutes as the undercooked beans are more harmful than the raw ones. Fermentation is often employed in many parts of Africa as it improves the nutritional value of beans by removing toxins. Inexpensive fermentation improves the nutritional value of the flour of beans and hence enhances digestibility as shown in a study carried out at Addis Ababa University. They are a major source of protein in Kenya, Malawi, Tanzania, Uganda and Zambia.
They contain significant amounts of fiber and soluble fiber. One cup of cooked beans provides about 9-13 grams of fiber. Soluble fiber helps to lower the cholesterol level. They also contain high levels of protein, complex carbohydrates, folate, and iron. Many edible beans especially the broad beans and the soy beans contain oligosaccharides which is a type of a sugar molecule as found in cabbage. An anti-oligosaccharide enzyme is required to digest these sugar molecules. The human digestive system lacks any anti-oligosaccharide enzyme these sugar molecules are particularly broken down by the bacteria present in the large intestine.
These sugars upon digestion produce flatulence-causing gases as a byproduct. Some species of molds produce alpha-galactosidase, an anti-oligosaccharide enzyme which facilitate the digestion of these oligosaccharide molecules more effectively in the small intestine if consumed by humans. These enzymes are sold in the markets under the trade name Beano in the United States. Beans can be cooked with natural carminatives like anise seeds, coriander seeds and cumin. They are also soaked in water and the vinegar is added to them. Brazil is the largest producer of beans followed by India and China.