Peanut (Latin, Arachis hypogaea, Fabaceae ), often referred to as groundnut, is a leguminous plant that produces fruit below ground. The growth habit of the peanut is indeterminate, indicating that vegetative and reproductive growth occur simultaneously on the same plant throughout a significant period of the plant’s life cycle. Peanut gynophores, which ultimately produce kernels enclosed by pods, are born above ground and move to the soil due to physiological processes where development and maturation occurs. Three botanical classifications of peanuts include Virginia, Spanish, and Valencia, which vary in vegetative and reproductive morphology. Pod and kernel size of peanuts belonging to these botanical classifications influence utilization and marketing.
Peanuts originated in South America in the region of northern Argentina, Bolivia, and Paraguay. Domestication of peanuts occurred slowly, in a manner similar to that of many other crop plants. During the early colonial period peanuts moved from South America to other areas, and they are now grown in many regions of the world, most notably Argentina, China, India, Indonesia, numerous countries in Africa, and the United States. Production per unit land area varies considerably across regions, and is affected by climate; soil and natural resources; production, pest management, and storage technology and capacity; management skills; and stability of governments and key infrastructure.
Peanut kernels contain 35 to 55 percent triacylglycerols (fresh weight) and 21 to 36 percent protein. Carbohydrate constitutes approximately 15 percent of peanuts, and key vitamins including ascorbic acid, niacin, riboflavin, and thiamin are found in peanuts. In addition to the positive attributes of peanut nutrition, peanuts act as an allergen in some segments of the human population. The nutritive value and possible allergic reaction influence peanut utilization and marketing.
The primary use of the peanut is for oil production. Peanuts are also used for human consumption in pastes and peanut butter, snack foods including a component in candies, and direct consumption with little to no additional processing after harvest. In developing countries, peanuts often are consumed directly or used as a component in local diets. In countries with intricate marketing systems, peanuts are often shelled, blanched, roasted, and in some cases salted. Components originating from these processes are also used in nonfood categories. However, its uses as oil and in products for direct human consumption are by far the most important uses of peanuts around the world.
The noted scientist George Washington Carver (c. 1864–1943) was responsible for an explosion in the number of uses for peanuts while he worked at the Tuskegee Institute in the United States. Over his distinguished career, Carver developed numerous uses and products derived from or containing peanuts. Perhaps the most notable product he helped introduce to a large segment of the population was peanut butter, which accounts for approximately half of peanut utilization in the United States. These products were important in establishing markets and supporting rural farming communities, and in combating poverty around the world, especially with respect to child development and health.
Production practices vary considerably around the world. In many regions of Africa, peanuts are produced at subsistence levels, yielding less than 1,000 kg/ha, using slash-and-burn techniques. In other regions, peanut yields can exceed 6,000 kg/ha when managed with intensive fertility and pest-management programs using modern machinery, and scientifically based principles and technology. Peanuts are susceptible to a wide range of insect and disease pests, nematodes, and weed interference, and they require essential elements, most notably calcium, and fertile soils with adequate drainage, to optimize yield. Because peanuts are consumed directly by humans, with limited post-harvest processing, it is important that peanut farmers develop strategies to minimize human and environmental exposure to pesticides.
Because peanuts are considered a staple in many regions of the world, the nutritive value of peanuts offers the possibility of its cultivation as a cash crop for local, regional, national, and international trade. In many countries, especially the United States, peanuts are grown primarily for domestic consumption. In contrast, some countries such as Argentina export a high percentage of peanuts produced domestically. Government legislation and farm programs, as well as regional agreements such as the North American Free Trade Agreement (NAFTA) and more inclusive agreements such as GATT (General Agreement on Tariffs and Trade), affect domestic and export marketing of peanuts. Relationships between the three major segments of the peanut industry—farmers, shellers, and manufacturers—can be complex and at times strained in free-market economies.
Peanuts have long been a key component of human diets around the world, especially with respect to providing oil and essential protein and vitamins, and they continue to be a staple food source, especially in rural regions of developing countries. Ensuring that final peanut products do not contain aflatoxin, a mycotoxin caused by the organism Aspregillus flavus, is important to protect human health. Additional research and education designed to minimize the negative effects of peanut allergens are also important in the utilization and marketing of peanuts. Increasing technology development and transfer to increase yield, improve quality, and minimize storage loss will continue to be important as human populations rise and concerns over environmental impacts increase. Developing fair-trade agreements and arrangements between major peanut-producing countries, especially those with export potential, is a continuing challenge.
SEE ALSO Agricultural Industry; Food; Industry; Third World
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David L. Jordan
Jan F. Spears