HOME

TheInfoList



OR:

''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the
spurge ''Euphorbia'' is a very large and diverse genus of flowering plants, commonly called spurge, in the family Euphorbiaceae. "Euphorbia" is sometimes used in ordinary English to collectively refer to all members of Euphorbiaceae (in deference to t ...
family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated as an annual crop in tropical and subtropical regions for its edible
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...
y tuberous root, a major source of
carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may o ...
s. Though it is often called ''yuca'' in parts of Spanish America and in the United States, it is not related to
yucca ''Yucca'' is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40–50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitis ...
, a shrub in the family Asparagaceae. Cassava is predominantly consumed in boiled form, but substantial quantities are used to extract cassava starch, called tapioca, which is used for food, animal feed, and industrial purposes. The Brazilian farinha, and the related ''
garri In West Africa, ''garri (also known as gari, galli'', or ''gali)'' is the flour of the fresh starchy cassava root. In the Hausa language, ''garri'' can also refer to the flour of guinea corn, maize, rice, yam, plantain and millet. F ...
'' of West Africa, is an edible coarse flour obtained by grating cassava roots, pressing moisture off the obtained grated pulp, and finally drying it (and roasting both in the case of farinha and garri). Cassava is the third-largest source of food carbohydrates in the tropics, after rice and
maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American English, North American and Australian English), is a cereal grain first domesticated by indigenous peoples of Mexico, indigenous ...
. Cassava is a major staple food in the developing world, providing a basic diet for over half a billion people. It is one of the most
drought-tolerant Drought tolerance is the ability to which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tolerance, detox ...
crops, capable of growing on marginal soils. Nigeria is the world's largest producer of cassava, while Thailand is the largest exporter of cassava starch. Cassava is classified as either sweet or bitter. Like other roots and tubers, both bitter and sweet varieties of cassava contain antinutritional factors and toxins, with the bitter varieties containing much larger amounts. It must be properly prepared before consumption, as improper preparation of cassava can leave enough residual
cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...
to cause acute cyanide intoxication, goiters, and even
ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...
, partial paralysis, or death. The more toxic varieties of cassava have been used in some places as
famine food A famine food or poverty food is any inexpensive or readily available food used to nourish people in times of hunger and starvation, whether caused by extreme poverty, such as during economic depression or war, or by natural disasters such a ...
during times of
food insecurity Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World ...
. Farmers often prefer the bitter varieties because they deter pests, animals, and thieves.


Description

The cassava root is long and tapered, with a firm, homogeneous flesh encased in a detachable rind, about thick, rough and brown on the outside. Commercial cultivars can be in diameter at the top, and around long. A woody vascular bundle runs along the root's axis. The flesh can be chalk-white or yellowish. Cassava roots are very rich in
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...
and contain small amounts of calcium (16 milligrams per 100 grams), phosphorus (27 mg/100 g), and vitamin C (20.6 mg/100 g). However, they are poor in
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
and other nutrients. In contrast, cassava leaves are a good source of protein for
animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...
and
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
nutrition, but deficient in the
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...
methionine.


Genome

The complete and haplotype-resolved African cassava (TME204) genome was reconstructed and made available using the Hi-C technology. The genome shows abundant novel gene loci with enriched functionality related to chromatin organization, meristem development, and cell responses. Differentially expressed transcripts of different haplotype origins were enriched for different functionality during tissue development. In each tissue, 20–30% of transcripts showed allele-specific expression differences with <2% of direction-shifting. Despite high gene synteny, the HiFi genome assembly revealed extensive chromosome rearrangements and abundant intra-genomic and inter-genomic divergent sequences, with significant structural variations mostly related to long terminal repeat retrotransposons.


Storage tuber

(FT) is a gene producing FT proteins which affect the formation of storage roots in many plants, including this one. Alleles in cassava include ''MeFT1'' and ''MeFT2''. ''MeFT1'' expression in leaves seems to not be photoperiodic, while ''MeFT2'' clearly is. ''MeFT1'' expression encourages motivation of sucrose towards the reproductive organs, as shown by experimental overexpression reducing storage root accumulation.


Taxonomy


History

Wild populations of ''M. esculenta'' subspecies ''flabellifolia'', shown to be the progenitor of domesticated cassava, are centered in west-central Brazil, where it was likely first domesticated no more than 10,000 years BP. Forms of the modern domesticated species can also be found growing in the wild in the south of Brazil. By 4,600 BC, cassava pollen appears in the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
lowlands, at the San Andrés archaeological site. The oldest direct evidence of cassava cultivation comes from a 1,400-year-old Maya site,
Joya de Cerén Joya de Cerén (''Jewel of Cerén'' in the Spanish language) is an archaeological site in La Libertad Department, El Salvador, featuring a pre-Columbian Maya farming village. The ancient Maya site of Joya de Cerén is located in the Zapotitán V ...
, in El Salvador. With its high food potential, it had become a staple food of the native populations of northern South America, southern Mesoamerica, and the Taino people in the Caribbean islands, who grew it using a high-yielding form of
shifting agriculture Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned while post-disturbance fallow vegetation is allowed to freely grow while the cultivator moves on to another plot. The period of cul ...
by the time of European contact in 1492. Cassava was a staple food of
pre-Columbian In the history of the Americas, the pre-Columbian era spans from the original settlement of North and South America in the Upper Paleolithic period through European colonization, which began with Christopher Columbus's voyage of 1492. Usually, ...
peoples in the Americas and is often portrayed in indigenous art. The Moche people often depicted yuca in their ceramics.
Spaniards Spaniards, or Spanish people, are a Romance ethnic group native to Spain. Within Spain, there are a number of national and regional ethnic identities that reflect the country's complex history, including a number of different languages, both ...
in their early occupation of Caribbean islands did not want to eat cassava or maize, which they considered insubstantial, dangerous, and not nutritious. They much preferred foods from Spain, specifically wheat bread, olive oil, red wine, and meat, and considered maize and cassava damaging to Europeans. The cultivation and consumption of cassava were nonetheless continued in both Portuguese and Spanish America. Mass production of cassava bread became the first Cuban industry established by the Spanish. Ships departing to Europe from Cuban ports such as
Havana Havana (; Spanish: ''La Habana'' ) is the capital and largest city of Cuba. The heart of the La Habana Province, Havana is the country's main port and commercial center.
,
Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whos ...
, Bayamo, and Baracoa carried goods to Spain, but sailors needed to be provisioned for the voyage. The Spanish also needed to replenish their boats with dried meat, water, fruit, and large amounts of cassava bread. Sailors complained that it caused them digestive problems. Tropical Cuban weather was not suitable for wheat planting and cassava would not go stale as quickly as regular bread. Cassava was introduced to Africa by Portuguese traders from Brazil in the 16th century. Around the same period, it was also introduced to Asia through Columbian Exchange by Portuguese and Spanish traders, planted in their colonies in Goa, Malacca, Eastern Indonesia, Timor and the Philippines.
Maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American English, North American and Australian English), is a cereal grain first domesticated by indigenous peoples of Mexico, indigenous ...
and cassava are now important staple foods, replacing native African crops in places such as Tanzania. Cassava has also become an important crop in Asia. While it is a valued food staple in parts of eastern Indonesia, it is primarily cultivated for starch extraction and bio-fuel production in Thailand, Cambodia and Vietnam. Cassava is sometimes described as the "bread of the tropics" but should not be confused with the tropical and equatorial bread tree ''(Encephalartos)'', the breadfruit ''(Artocarpus altilis)'' or the
African breadfruit ''Treculia africana'' is a tree species in the genus '' Treculia'' which can be used as a food plant and for various other traditional uses. The fruits are hard and fibrous, can be the size of a volleyball and weight up to . Chimpanzees have been ...
''(Treculia africana)''. This description definitely holds in Africa and parts of South America; in Asian countries such as Vietnam fresh cassava barely features in human diets.Mota-Guttierez and O'Brien
Cassava consumption and the occurrence of cyanide in cassava in Vietnam, Indonesia and Philippines
Public Health Nutrition, 2019
There is a legend that cassava was introduced in 1880–1885 CE to the South Indian state of
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South Ca ...
by the King of
Travancore The Kingdom of Travancore ( /ˈtrævənkɔːr/), also known as the Kingdom of Thiruvithamkoor, was an Indian kingdom from c. 1729 until 1949. It was ruled by the Travancore Royal Family from Padmanabhapuram, and later Thiruvananthapuram. A ...
, Vishakham Thirunal Maharaja, after a great famine hit the kingdom, as a substitute for rice.Saraswathy Nagarajan
"How tapioca came to Travancore"
''The Hindu'', June 27, 2019
However, there are documented cases of cassava cultivation in parts of the state before the time of Vishakham Thirunal Maharaja. Cassava is called kappa or maricheeni in
Malayalam Malayalam (; , ) is a Dravidian language spoken in the Indian state of Kerala and the union territories of Lakshadweep and Puducherry ( Mahé district) by the Malayali people. It is one of 22 scheduled languages of India. Malayalam wa ...
. It is also referred to as tapioca in Indian English usage.


Cultivation


Pests

A major cause of losses during cassava storage is infestation by insects. A wide range of species that feed directly on dried cassava chips have been reported as a major factor in spoiling stored cassava, with losses between 19% and 30% of the harvested produce. In
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, a previous issue was the cassava mealybug ('' Phenacoccus manihoti'') and cassava green mite (''
Mononychellus tanajoa ''Mononychellus tanajoa'', the cassava green mite, is a species of spider mite Spider mites are members of the Tetranychidae family, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live ...
''). These pests can cause up to 80 percent crop loss, which is extremely detrimental to the production of subsistence farmers. These pests were rampant in the 1970s and 1980s but were brought under control following the establishment of the Biological Control Centre for Africa of the
International Institute of Tropical Agriculture The International Institute of Tropical Agriculture (IITA) is a nonprofit organization that works with partners to enhance crop quality and productivity, reduce producer and consumer risks, and generate wealth from agriculture, with the ultimate ...
(IITA) under the leadership of Hans Rudolf Herren. The Centre investigated biological control for cassava pests; two
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
n natural enemies ''Anagyrus lopezi'' (a parasitoid wasp) and '' Typhlodromalus aripo'' (a predatory mite) were found to effectively control the cassava mealybug and the cassava green mite, respectively. Several viruses are of economic importance. The
African cassava mosaic virus ''African cassava mosaic virus'' (ACMV, ICTV approved acronym) is a plant pathogenic virus of the family '' Geminiviridae'' that may cause either a mosaic appearance to plant leaves, or chlorosis, a loss of chlorophyll. In ''Manihot esculenta'' ...
causes the leaves of the cassava plant to wither, limiting the growth of the root. An outbreak of the virus in Africa in the 1920s led to a major famine. The virus is spread by the whitefly and by the transplanting of diseased plants into new fields. Sometime in the late-1980s, a mutation occurred in Uganda that made the virus even more harmful, causing the complete loss of leaves. This mutated virus spread at a rate of per year, and as of 2005 was found throughout
Uganda }), is a landlocked country in East Africa. The country is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the south by Tanzania. The ...
, Rwanda, Burundi, the
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
and the Republic of the Congo. Altogether viruses are a severe production limitation in the tropics. They are the primary reason for the complete lack of yield increases in the 25 years .
Cassava brown streak virus disease Cassava brown streak virus disease (CBSD) is a damaging disease of cassava plants, and is especially troublesome in East Africa. It was first identified in 1936 in Tanzania, and has spread to other coastal areas of East Africa, from Kenya to Moza ...
has been identified as a major threat to cultivation worldwide.
Cassava mosaic virus ''Manihot esculenta'', common name, commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively ...
(CMV) is widespread in Africa, causing cassava mosaic disease (CMD). Bredeson et al 2016 find the ''M. esculenta'' cultivars most widely used on that continent have ''M. carthaginensis'' subsp. ''glaziovii'' genes of which some appear to be CMD resistance genes. Although the ongoing CMD pandemic affects both East- and Central- Africa, Legg ''et al.'', 2014 finds these two areas have two distinct subpopulations of the vector, '' Bemisia tabaci'' whiteflies. A wide range of plant parasitic nematodes have been reported associated with cassava worldwide. These include '' Pratylenchus brachyurus'', '' Rotylenchulus reniformis'', '' Helicotylenchus'' spp., ''
Scutellonema ''Scutellonema'' is a genus of nematodes The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They a ...
'' spp. and ''
Meloidogyne Root-knot nematodes are plant-parasitic nematodes from the genus ''Meloidogyne''. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause appro ...
'' spp., of which '' Meloidogyne incognita'' and '' Meloidogyne javanica'' are the most widely reported and economically important. ''Meloidogyne'' spp. feeding produces physically damaging galls with eggs inside them. Galls later merge as the females grow and enlarge, and they interfere with water and nutrient supply. Cassava roots become tough with age and restrict the movement of the juveniles and the egg release. It is therefore possible that extensive galling can be observed even at low densities following infection. Other pests and diseases can gain entry through the physical damage caused by gall formation, leading to rots. They have not been shown to cause direct damage to the enlarged storage roots, but plants can have reduced height if there was loss of enlarged root weight. Research on nematode pests of cassava is still in the early stages; results on the response of cassava is, therefore, not consistent, ranging from negligible to seriously damaging. Since nematodes have such a seemingly erratic distribution in cassava agricultural fields, it is not easy to clearly define the level of direct damage attributed to nematodes and thereafter quantify the success of a chosen management method. The use of nematicides has been found to result in lower numbers of galls per feeder root compared to a control, coupled with a lower number of rots in the storage roots. The organophosphorus nematicide femaniphos, when used, did not affect crop growth and yield parameter variables measured at harvest. Nematicide use in cassava is not terribly effective at increasing harvested yield, but lower infestation at harvest and lower subsequent storage loss provide a higher effective yield. The use of tolerant and resistant cultivars is the most practical management method in most locales. This crop suffers from a rust, caused by '' Uromyces manihotis''.


Harvesting

Cassava is harvested by hand by raising the lower part of the stem, pulling the roots out of the ground, and removing them from the base of the plant. The upper parts of the stems with the leaves are plucked off before harvest. Cassava is propagated by cutting the stem into sections of approximately 15 cm, these being planted prior to the wet season. Cassava growth is favorable under temperatures ranging from , but it can tolerate temperatures as low as and as high as .


Postharvest handling and storage

Cassava undergoes post-harvest physiological deterioration (PPD) once the tubers are separated from the main plant. The tubers, when damaged, normally respond with a healing mechanism. However, the same mechanism, which involves
coumaric acid Coumaric acid is a phenolic derivative of cinnamic acid having a hydroxy group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. I ...
s, starts about 15 minutes after damage, and fails to switch off in harvested tubers. It continues until the entire tuber is oxidized and blackened within two to three days after harvest, rendering it unpalatable and useless. PPD is related to the accumulation of reactive oxygen species (ROS) initiated by cyanide release during mechanical harvesting. Cassava shelf life may be increased up to three weeks by overexpressing a cyanide-insensitive alternative oxidase, which suppressed ROS by 10-fold. PPD is one of the main obstacles preventing farmers from exporting cassavas abroad and generating income. Fresh cassava can be preserved like potato, using thiabendazole or bleach as a fungicide, then wrapping in plastic, coating in wax or freezing. While alternative methods for PPD control have been proposed, such as preventing ROS effects by use of plastic bags during storage and transport, coating the roots with wax, or freezing roots, such strategies have proved to be economically or technically impractical, leading to
breeding Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and r ...
of cassava varieties more tolerant to PPD and with improved durability after harvest. Plant breeding has resulted in different strategies for cassava tolerance to PPD. One was induced by mutagenic levels of
gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s, which putatively silenced one of the genes involved in PPD genesis, while another was a group of high- carotene clones in which the antioxidant properties of carotenoids are postulated to protect the roots from PPD.


Production

In 2020, global production of cassava root was 303 million
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
s, with
Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
as the world's largest producer, producing 20% of the world total (table). Other major growers were
Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
and
Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...
. Cassava is one of the most
drought-tolerant Drought tolerance is the ability to which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tolerance, detox ...
crops, can be successfully grown on marginal soils, and gives reasonable yields where many other crops do not grow well. Cassava is well adapted within latitudes 30° north and south of the equator, at elevations between sea level and above sea level, in equatorial temperatures, with rainfalls from annually, and to poor soils with a pH ranging from acidic to alkaline. These conditions are common in certain parts of Africa and South America. Cassava is a highly productive crop when considering food energy produced per unit land area per day – , as compared with for rice, for wheat and for maize.


Toxicity

Cassava roots, peels and leaves should not be consumed raw because they contain two cyanogenic glucosides, linamarin and lotaustralin. These are decomposed by linamarase, a naturally occurring
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
in cassava, liberating hydrogen cyanide (HCN). Cassava varieties are often categorized as either bitter or sweet, signifying the presence or absence of toxic levels of cyanogenic glucosides, respectively. The so-called sweet (more accurately non-bitter) cultivars can produce as little as 20 milligrams of
cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...
(CN) per kilogram of fresh roots, whereas bitter ones may produce more than 50 times as much (1 g/kg). Cassavas grown during
drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D.  Jiang, A.  Khan, W.  Pokam Mba, D.  Rosenfeld, J. Tierney, an ...
are especially high in these toxins. A dose of 25 mg of pure cassava cyanogenic glucoside, which contains 2.5 mg of cyanide, is sufficient to kill a rat. Excess cyanide residue from improper preparation is known to cause acute cyanide intoxication, and goiters, and has been linked to ataxia (a neurological disorder affecting the ability to walk, also known as '' konzo''). It has also been linked to tropical calcific
pancreatitis Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic p ...
in humans, leading to chronic pancreatitis. Symptoms of acute cyanide intoxication appear four or more hours after ingesting raw or poorly processed cassava: vertigo, vomiting, and collapse. In some cases, death may result within one or two hours. It can be treated easily with an injection of
thiosulfate Thiosulfate ( IUPAC-recommended spelling; sometimes thiosulphate in British English) is an oxyanion of sulfur with the chemical formula . Thiosulfate also refers to the compounds containing this anion, which are the salts of thiosulfuric acid, e ...
(which makes sulfur available for the patient's body to detoxify by converting the poisonous cyanide into thiocyanate). "Chronic, low-level cyanide exposure is associated with the development of goiter and with tropical ataxic neuropathy, a nerve-damaging disorder that renders a person unsteady and uncoordinated. Severe cyanide poisoning, particularly during famines, is associated with outbreaks of a debilitating, irreversible paralytic disorder called konzo and, in some cases, death. The incidence of konzo and
tropical ataxic neuropathy Tropical ataxic neuropathy (TAN, also known as Strachan-Scott Syndrome and prisoners of war neuropathy) is a disease or category of diseases that commonly causes disability and increases mortality. The causes of TAN are not understood; there is no ...
can be as high as three percent in some areas." During the
shortages in Venezuela Shortages in Venezuela of regulated food staples and basic necessities have been widespread following the enactment of price controls and other policies under the government of Hugo Chávez and exacerbated by the policy of withholding United ...
in the late 2010s, dozens of deaths were reported due to Venezuelans resorting to eating bitter cassava in order to curb starvation. Cases of cassava poisoning were also documented during the famine accompanying the Great Leap Forward (1958–1962) in China. Societies that traditionally eat cassava generally understand that some processing (soaking, cooking, fermentation, etc.) is necessary to avoid getting sick. Brief soaking (four hours) of cassava is not sufficient, but soaking for 18–24 hours can remove up to half the level of cyanide. Drying may not be sufficient, either. For some smaller-rooted, sweet varieties, cooking is sufficient to eliminate all toxicity. The cyanide is carried away in the processing water and the amounts produced in domestic consumption are too small to have environmental impact. The larger-rooted, bitter varieties used for production of flour or starch must be processed to remove the cyanogenic glucosides. The large roots are peeled and then ground into flour, which is then soaked in water, squeezed dry several times, and toasted. The starch grains that flow with the water during the soaking process are also used in cooking. The flour is used throughout
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
and the
Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
. Industrial production of cassava flour, even at the cottage level, may generate enough cyanide and cyanogenic glycosides in the effluents to have a severe environmental impact.


Uses


Alcoholic beverages

Alcoholic beverages made from cassava include
cauim Cauim is a traditional alcoholic beverage or beer of the indigenous peoples in Brazil since pre-Columbian times. It is still made today in remote areas throughout Panama and South America. Cauim is made by fermenting manioc (a large starchy root), ...
and tiquira (Brazil), kasiri (Guyana, Suriname), impala (Mozambique), masato (Peruvian Amazonia chicha), parakari or kari (Guyana),
nihamanchi Nihamanchï is a beer brewed from manioc (''Manihot esculenta'') by indigenous peoples of South America. It is also known as nihamanci, nijimanche,Howell 49 or nijiamanchi, and is related to chicha. Jívaro women make it by chewing manioc tubers, ...
(South America) also known as (Ecuador and Peru), ö döi (chicha de yuca, Ngäbe-Bugle, Panama), sakurá (Brazil, Suriname), and tarul ko (Darjeeling, Sikkim, India).


Culinary

Cassava-based dishes A great variety of cassava-based dishes are consumed in the regions where cassava (''Manihot esculenta'', also called 'manioc' or 'yuca') is cultivated, and the ingredient is included many national or ethnic specialities. As a food ingredient, ca ...
are widely consumed wherever the plant is cultivated; some have regional, national, or ethnic importance. Cassava must be cooked properly to detoxify it before it is eaten. Cassava can be cooked in many ways. The root of the sweet variety has a delicate flavor and can replace potatoes. It is used in
cholent Cholent and other Sabbath stews ( yi, טשאָלנט, tsholnt ''or'' tshulnt) are traditional Jewish stews. It is usually simmered overnight for 10–12 hours or more, and eaten for lunch on Shabbat (the Sabbath). Shabbat stews were develo ...
in some households. It can be made into a flour that is used in breads, cakes and cookies. In Brazil, detoxified cassava is ground and cooked to a dry, often hard or crunchy meal known as ''
farofa ''Farofa'' () is a type of meal made from toasted cassava. It is eaten mainly in Brazil. It can be found commercially produced and packaged but can also be prepared at home based on family recipes. Most recipes will also contain varying amou ...
'' used as a condiment, toasted in butter, or eaten alone as a side dish.


Preparation

A safe processing method known as the "wetting method" is to mix the cassava flour with water into a thick paste, spread it in a thin layer over a basket and then let it stand for five hours at 30 °C in the shade. In that time, about 83% of the cyanogenic
glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...
s are broken down by the linamarase; the resulting hydrogen cyanide escapes to the atmosphere, making the flour safe for consumption the same evening. The traditional method used in West Africa is to peel the roots and put them into water for three days to ferment. The roots are then dried or cooked. In Nigeria and several other west African countries, including Ghana, Cameroon, Benin, Togo, Ivory Coast, and Burkina Faso, they are usually grated and lightly fried in palm oil to preserve them. The result is a foodstuff called ''gari''. Fermentation is also used in other places such as Indonesia (see
Tapai ''Tapai'' (also ''tapay'' or ''tape'') is a traditional fermented preparation of rice or other starchy foods, and is found throughout much of Southeast Asia, especially in Austronesian cultures, and parts of East Asia. It refers to both t ...
). The fermentation process also reduces the level of antinutrients, making the cassava a more nutritious food. The reliance on cassava as a food source and the resulting exposure to the goitrogenic effects of thiocyanate has been responsible for the endemic goiters seen in the Akoko area of southwestern
Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
. A project called "BioCassava Plus" uses bioengineering to grow cassava with lower cyanogenic glycosides combined with
fortification A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere ...
of vitamin A,
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...
and
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
to improve the nutrition of people in
sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...
.


Nutrition

Raw cassava is 60% water, 38% carbohydrates, 1%
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
, and has negligible fat (table). In a reference serving, raw cassava provides of food energy and 25% of the Daily Value (DV) of vitamin C, but otherwise has no micronutrients in significant content (i.e. above 10% of the relevant DV). Cooked cassava starch has a digestibility of over 75%. Cassava, like other foods, also has antinutritional and toxic factors. Of particular concern are the cyanogenic glucosides of cassava ( linamarin and lotaustralin). On hydrolysis, these release hydrogen cyanide (HCN). The presence of cyanide in cassava is of concern for human and for animal consumption. The concentration of these antinutritional and unsafe glycosides varies considerably between varieties and also with climatic and cultural conditions. Selection of cassava species to be grown, therefore, is quite important. Once harvested, bitter cassava must be treated and prepared properly prior to human or animal consumption, while sweet cassava can be used after boiling.


Comparison with other major staple foods

A comparative table shows that cassava is a good energy source. In its prepared forms, in which its toxic or unpleasant components have been reduced to acceptable levels, it contains an extremely high proportion of starch compared to most staples. However, cassava is a poorer dietary source of protein and most other essential nutrients. Though an important staple, its main value is as a component of a balanced diet. Comparisons between the nutrient content of cassava and other major staple foods when raw must be interpreted with caution because most staples are not edible in such forms and many are indigestible, even dangerously poisonous or otherwise harmful. For consumption, each must be prepared and cooked as appropriate.


Biofuel

In many countries, significant research has begun to evaluate the use of cassava as an
ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
biofuel feedstock. Under the Development Plan for Renewable Energy in the Eleventh Five-Year Plan in the
People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
, the target was to increase the production of ethanol fuel from nongrain feedstock to two million tonnes, and that of biodiesel to 200 thousand tonnes by 2010. This is equivalent to the replacement of 10 million tonnes of petroleum. This push for non-grain ethanol was further increased to a goal of 300 million tons of cellulosic and non-grain based ethanol combined by 2020. As a result, cassava (tapioca) chips have gradually become a major source of ethanol production. On 22 December 2007, the largest cassava
ethanol fuel Ethanol fuel is ethyl alcohol, the same type of alcohol found in alcoholic beverages, used as fuel. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline. The first production car running entirely on ethanol was t ...
production facility was completed in Beihai, with annual output of 200 thousand tons, which would need an average of 1.5 million tons of cassava. In November 2008, China-based Hainan Yedao Group invested US$51.5 million in a new biofuel facility that is expected to produce a year of bioethanol from cassava plants.


Animal feed

Cassava tubers and hay are used worldwide as animal feed. Cassava hay is harvested at a young growth stage (three to four months) when it reaches about above ground; it is then sun-dried for one to two days until its final dry matter content approaches 85 percent. Cassava hay contains high protein (20–27 percent crude protein) and condensed tannins (1.5–4 percent CP). It is valued as a good roughage source for ruminants such as cattle.


Laundry starch

Cassava is also used in a number of commercially available laundry products, especially as starch for shirts and other garments. Using cassava starch diluted in water and spraying it over fabrics before ironing helps stiffen collars.


Economic importance

Cassava, yams ('' Dioscorea'' spp.), and sweet potatoes (''Ipomoea batatas'') are important sources of food in the tropics. The cassava plant gives the third-highest yield of carbohydrates per cultivated area among crop plants, after
sugarcane Sugarcane or sugar cane is a species of (often hybrid) tall, perennial grass (in the genus '' Saccharum'', tribe Andropogoneae) that is used for sugar production. The plants are 2–6 m (6–20 ft) tall with stout, jointed, fibrous stalk ...
and
sugar beet A sugar beet is a plant whose root contains a high concentration of sucrose and which is grown commercially for sugar production. In plant breeding, it is known as the Altissima cultivar group of the common beet ('' Beta vulgaris''). Together ...
s. Cassava plays a particularly important role in agriculture in developing countries, especially in
sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...
, because it does well on poor soils and with low rainfall, and because it is a perennial that can be harvested as required. Its wide harvesting window allows it to act as a famine reserve and is invaluable in managing labor schedules. It offers flexibility to resource-poor farmers because it serves as either a subsistence or a cash crop. Worldwide, 800 million people depend on cassava as their primary food staple. No continent depends as much on root and tuber crops in feeding its population as does Africa. In the humid and sub-humid areas of tropical Africa, it is either a primary staple food or a secondary costaple. In Ghana, for example, cassava and yams occupy an important position in the agricultural economy and contribute about 46 percent of the agricultural gross domestic product. Cassava accounts for a daily caloric intake of 30 percent in Ghana and is grown by nearly every farming family. The importance of cassava to many Africans is epitomised in the Ewe (a language spoken in Ghana, Togo and
Benin Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the nort ...
) name for the plant, ''agbeli'', meaning "there is life". In
Tamil Nadu Tamil Nadu (; , TN) is a state in southern India. It is the tenth largest Indian state by area and the sixth largest by population. Its capital and largest city is Chennai. Tamil Nadu is the home of the Tamil people, whose Tamil language ...
, India, there are many cassava processing factories alongside National Highway 68 between Thalaivasal and Attur. Cassava is widely cultivated and eaten as a staple food in
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
and in
Kerala Kerala ( ; ) is a state on the Malabar Coast of India. It was formed on 1 November 1956, following the passage of the States Reorganisation Act, by combining Malayalam-speaking regions of the erstwhile regions of Cochin, Malabar, South Ca ...
. In
Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...
it is an important source of carbohydrates especially for natives of hilly areas. In the subtropical region of southern China, cassava is the fifth-largest crop in terms of production, after rice, sweet potato, sugar cane, and
maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American English, North American and Australian English), is a cereal grain first domesticated by indigenous peoples of Mexico, indigenous ...
. China is also the largest export market for cassava produced in Vietnam and Thailand. Over 60 percent of cassava production in China is concentrated in a single province,
Guangxi Guangxi (; ; alternately romanized as Kwanghsi; ; za, Gvangjsih, italics=yes), officially the Guangxi Zhuang Autonomous Region (GZAR), is an autonomous region of the People's Republic of China, located in South China and bordering Vietnam ...
, averaging over seven million tonnes annually.


See also

*
Akyeke Acheke ( Ebrié: , bm, acɛkɛ), also spelled attiéké ( Ivory Coast), "attcheke" or akyeke ( Ghana), is a side dish made from cassava that is popular and traditional in West Africa. The dish is prepared from fermented cassava pulp that has be ...
* Attiéké a side dish made from cassava that is a part of the cuisine of Côte d'Ivoire in Africa * Columbian Exchange * Couac *
Fufu Fufu (or fufuo, foofoo, foufou ) is a dough-like food found in West African cuisine. In addition to Ghana, it is also found in Sierra Leone, Guinea, Liberia, Cote D'Ivoire, Benin, Togo, Nigeria, Cameroon, the Democratic Republic of Congo, the ...
* Kwanga * Kasiri *
Maní (Amazonian legend) Maní, a Tupí myth of origins, is the name of an indigenous girl with very fair complexion. The Amazonian legend of Maní is related to the cult of Manioc ''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous ...
* Tapioca industry of Thailand *
Yellow cassava Yellow cassava is a new, yellow-fleshed breed of one of the most popular root crops in the tropics. Regular cassava is a staple crop in tropical countries which 300 million people rely upon for at least 10% of their daily caloric intake, in 15 Af ...


References


External links


Cassava – Purdue University Horticulture




{{Authority control Manihoteae Biofuels Caribbean cuisine Central American cuisine Crops originating from South America Crops Flora of Jamaica Flora of South America French Guianan cuisine Jamaican cuisine Root vegetables Staple foods Tropical agriculture Tubers Crops originating from indigenous Americans Flora without expected TNC conservation status