Legumes such as beans, lentils, peas and soya products are seeds, pods, or other edible parts of a leguminous plants which can be consumed in many forms including split, ground in to flours or dried, canned, cooked or frozen whole legumes. They are famous for their low fat and high protein content which is an important part of a healthy diet especially for non-meat eaters. Legumes are also a great sources of mineral, antioxidant and fiber.
Legumes are members of a family of flowering plants known as Leguminosae. It is one of the three largest families of flowering plants, with approximately 690 genera and about 18,000 species. . These legumes originated in humid, subhumid, cool season, subtropical, semiarid, and temperate areas in diverse regions ranging from Southwest Asia and East Asia to the Mediterranean and South America.
The legume pod is modified in many ways and comes in a variety of shapes, sizes and colours to facilitate dispersal by animals, wind, and water. Legumes rapidly spread around the world, acquiring more and more specifically legume characteristics along the way, while diversifying into the tremendous number of species that exist today. Legumes are found in nearly all terrestrial biomes on all continents except Antarctica. Archaeological evidence indicated the first species were discovered around 59 million years ago.
Lentils and garbanzo were the first cultivated legumes in the Mediterranean at least 10,000 years ago. Throughout that time humans had figured out that beans must be prepared by soaking, cooking, fermenting, or sprouting in order to make them edible as some are toxic if eaten raw. At least 8,000 years ago, ancient people in Peru began cultivating lima beans and peanuts. Domestication of these legumes spread throughout South America and as far north as Mexico over the following several centuries. On the other side of the world soy beans were domesticated by farmers in northern China which is one of the most popular legumes today. By the first century A.D., it had spread to many parts of Asia and moved to Europe and North America in the eighteenth century. By around 500 B.C., the Greeks and Romans were cultivating peas which was commercialised by street vendors in Athens. Archaeological evidence suggests that these peas must have been grown in the eastern Mediterranean and Mesopotamian regions at least 5,000 years ago and in Britain as early as the 11th century.
By the first century A.D., there were major civilizations firmly established in numerous locations on every continent on Earth (except Australia), and legumes were playing a big part in the diets and the commerce of each one. India is the world's largest producer and the largest consumer of pulses with the global pulse market estimated at 60 million tonnes. Beans have among the highest protein content of all plant foods and are, for that reason, known as poor people’s food. Legumes are nutritionally important for people who cannot or choose not to eat meat. The amino acids found in meat are perfectly complemented by those in cereals.
An estimated amount of 80% of Earth’s atmosphere is nitrogen gas (N2) which, unfortunately, is impractical to most living organisms. Biological nitrogen fixation is the process that changes inert Nitrogen gas (N2 ) into biologically useful ammonia (NH3). This process is mediated in nature only by nitrogen fixing bacteria. This special way of obtaining nitrogen allows for the formation of amino acids, an essential building-block of proteins all plants and animals use to survive. One of the characteristics that make legumes unique in the plant world is that they have symbiotic nitrogen-fixing bacteria in structures called root nodules. Within these nodules NH3 is produced and absorbed by the plant. Nitrogen fixation by legumes is a partnership between a bacterium and a plant and therefore, they play a key role in crop rotation. This process is why legumes are among the best plant-based sources of dietary protein. Some legumes are better at fixing nitrogen than others. Common beans are poor fixers where as other grain legumes, such as peanuts, cowpeas, soybeans, and fava beans, are good nitrogen fixers and will more than often produce extra ammonia which is absorbed into the soil.
High in plant based proteins with a hearty dose of dietary fibers, potassium and complex carbohydrates, legumes have been shown to help manage both cholesterol, blood glucose and weight. Protein is critical to cellular function and muscle growth and therefore a crucial part to your diet. They are nutrient dense, more specifically B-group vitamins, iron, calcium, phosphorus, zinc and magnesium, good source of folate. Increased intakes are linked to reduced risk of heart disease, diabetes and some cancers. In addition, emerging evidence indicates legumes may help in weight management as they are low in calories and increase metabolism. Their low glycemic index contributes to satiating effect of a meal and may reduce insulin response. In addition, their high resistant starch content to shorten chain fatty acids adds to colonic health benefits and protects against chronic diseases. High levels of Phytochemical content is said to play a role in the disease protection benefits of legumes. Legumes are also sources of phytosterols, isoflavones, saponins, and alkaloids, as well as some bioactive sugars, oligosaccharides and phytates. For this reason, legumes are an excellent way to round out a diet that may be lacking in certain nutrients.