Cassava ( Manihot esculenta ),
The manioc ( Manihot esculenta ) is a species of the genus Manihot in the family of the milkweed family (Euphorbiaceae). Other names for this crop and its agricultural product (harvested tubers) are Mandi'o (Paraguay), Mandioca (Brazil, Argentina, Paraguay), cassava , cassava or in Spanish-speaking Latin America Yuca . The cultivation of the plant is widespread because of its starchy root tubers. The starch processed is called tapioca . It originally comes from South America and was already used by the indigenous people for nutrition. It is now grown worldwide in many parts of the tropics and subtropics . Other species from the genus Manihot are also used as starch suppliers.
Cassava is known by different names. The name cassava comes from the word Maniot in the Tupi-Guarani language, which was originally widespread on the Brazilian Atlantic coast . Today the Guarani word mandi'o is used in Paraguay . In Brazil today, cassava is called mandioca , which is derived from the name of the woman Mandi-Oca (or mãdi'og ) - according to a legend of the Brazilian natives, the cassava plant is said to have sprung from her body. The name cassava comes from the Arawak word Kasabi and the word Yuca comes from the language of the Caribs .
Cassava plants are shrubs with a stature height of 1.5 m to 5 m. All parts of the plant carry milky sap . Seedlings initially form a taproot . The fibrous side roots thicken and form large, spindle-shaped root tubers . The stems show different growth patterns depending on the variety : with strong branching from the base or with a continuous, less branched main shoot. The leaves are hand-shaped divided into three to nine segments; each measures 8 cm to 18 cm in length and 1.5 cm to 4 cm in width. The leaves are on 6 cm to 35 cm long petioles. At the base of the petiole there are two triangular to lanceolate stipules . These are 5 mm to 7 mm long, they have entire margins or are divided into a few prickly-pointed segments. The leaves are shed during dry periods.
The paniculate , 5 cm to 8 cm large inflorescences can be terminal or stand in the leaf axils. There are male and female flowers that both appear on the same plant ( monoecia ). The short and thinly stalked smaller male flowers consist of five yellowish to whitish and reddish to purple tepals that are fused together up to half their length or less. They are hairy on the inside. The longer, curvy and thicker stalked female flowers also have five tepals that are not very fused with one another, these are 1 cm in length larger than those of the male flowers. The draft tube, rippige ovary is upper constant, the pen are very short with fleshy and frilly scars . A pistillode may be present in the male flowers. Ten stamens are formed in two circles with elongated anthers, the outer ones are longer. Staminodes may be present in the female flowers. The flowers each have a multi-lobed and fleshy, yellowish to reddish discus .
The egg-shaped to roundish, septicidal-loculicidal capsule fruit is oval, 1.5 cm to 1.8 cm long and 1.0 cm to 1.5 cm wide. It has six longitudinal ribs and contains three smooth, slightly triangular, about 1 cm large, dark brown, gray speckled seeds . The caruncula still clings to fresh seeds .
The number of chromosomes is 2n = 36, less often 30 or 54.
The female flowers ripen before the male ( protogyny ), so that self-pollination is avoided. Artificially induced self-pollination results in inbreeding depression . The flowers contain nectar, which attracts insects as pollinators. The fruits burst open when ripe and throw the seeds out.
Cassava plants prefer sandy or sandy-loamy soils. Growth is best on slightly acidic substrate, but a wide range of pH 4 to 8 is tolerated. Cassava copes well with typical tropical soils, which are high in aluminum and manganese and have few nutrients available. They survive dry periods well by shedding the leaves, and after the onset of rain they sprout again quickly. Cassava requires a sunny location, temperatures below 10 ° C are not tolerated.
Cassava is known only from culture, he is probably as allotetraploide plant from South America manioc arose species. The origin of the cassava plant is not exactly clear, both South and Central America are possible places of origin. The oldest archaeological finds of cassava remains were made in Mexico , their age is estimated to be 2800 years. Goiás , the hinterland of Bahia or the Amazon region are also possible places of origin . It is also conceivable that the cassava was domesticated independently in Central and South America. Cassava was grown in the Moxos Plain over 10,000 years ago.
What is certain is that the cassava came to the Caribbean from South America . The Caribs and Arawak already knew cassava when they settled the Caribbean islands from the south, and they already had knowledge of the reproduction, cultivation and processing of the plants during their migration.
The oldest European description of cassava dates back to 1494. The Spaniards came across the plant in the Caribbean and the Portuguese in what is now Brazil, and bread made from poisonous roots was reported . In the colonial societies of Central and South America, cassava quickly became very important for the diet of the settlers and slaves . While the fertile land was used for growing sugar cane , less fertile fields were planted with cassava. Impoverished peasants and runaway slaves grew cassava and sold it to the cities and to the sugar planters. The manioc flour, which can be kept even at tropical temperatures, served soldiers and conquerors ( bandeirantes ) as provisions.
The Portuguese brought cassava to Africa, both in the form of flour or bread as food for the slaves during their transport from Africa to America, and in the form of plants that were to be propagated in Africa. Together with the plants, knowledge about their cultivation and above all the correct processing had to be passed on. The Portuguese only succeeded in introducing cassava in what is now Angola , which is probably due to the good relations with the Bakongo kings who ruled in the 15th century . The cultivation of cassava spread rapidly, especially in the rainforest of what is now the Congo.
In West Africa, where the Portuguese tried in vain to introduce cassava, the plant was not accepted by the population until the 19th century. The manioc cultivation was mediated by freed slaves who had returned from America, the colonial rulers promoted the manioc cultivation as a measure to avoid famine. In East Africa, cassava was introduced by the Portuguese and French in the 18th century, although the latter also had difficulties conveying the correct processing of the roots: in Madagascar , the first attempts at growing cassava were associated with mass poisoning.
Manioc began to be introduced in Asia as early as the 17th century. This was first achieved on the Moluccas , later on Java and in the 18th century in Goa and on the islands in the Indian Ocean . In Indonesia and India, the colonial powers promoted the cultivation of cassava with the aim of avoiding famine. Cassava also made it to China, but is only grown there to a limited extent as fodder.
How the cassava got to the Pacific islands is not exactly clear. A Spanish expedition reported about cassava cultivation on Easter Island as early as 1770 , which would support theories of the colonization of Oceania from South America. It is better documented that the plant was brought to Tahiti by the English in the 19th century and spread from there to all the other Pacific islands. Today cassava is widely grown in the tropics, especially in regions with a dry season.
In 2018, around 278 million t of cassava (manioc) were harvested worldwide. The 20 largest producer countries together harvested around 91.1% of the world harvest.
(in t )
|3||Democratic Republic of Congo||29,952,479||13||Cameroon||5,030,364|
|5||Brazil||17,644,733||15th||People's Republic of China||4,915,255|
The root tubers are mainly used as food, occasionally the leaves are also used as vegetables. The 0.15 m to 1 m long and 3 cm to 15 cm thick tubers can weigh up to 10 kg. They are surrounded by a corked, usually reddish-brown outer layer, inside they are usually white, occasionally yellow or reddish.
|Contains 100 g cassava (edible portion)|
|component||Amount in the tuber||Amount in the sheet|
|water||60 g||no data|
|Proteins||1.2 g||no data|
|carbohydrates||35 g||no data|
|Fats||0.3 g||no data|
|Fiber||1.4 g||no data|
|phosphorus||75 mg||116 mg|
|calcium||35 mg||297 mg|
|iron||0.7 mg||7.8 mg|
|Vitamin A||traces||12450 IU|
|vitamin C||36 mg||316 mg|
|Vitamin B1||0.05 mg||0.26 mg|
|Vitamin B2||0.03 mg||0.5 mg|
|niacin||0.7 mg||3 mg|
In the raw state, the root tubers are poisonous because they contain glucosides , mainly linamarine . This cyanogenic glycoside is stored in the vacuole of the plant cell and has no toxic effect. However, if the plant is injured (e.g. by predators), the substance comes into contact with the enzyme linamarase and D-glucose is split off. The resulting acetone cyanohydrin can break down spontaneously or catalyzed by the enzyme hydroxynitrile lyase to acetone and hydrocyanic acid . The content of toxic substances is strongly dependent on the variety, so-called "sweet" varieties contain only a small amount of glucoside.
Symptoms of poisoning are, for example, ataxia or optic atrophy . Hydrocyanic acid evaporates at room temperature, but in order to cause complete outgassing, the tuber has to be chopped up thoroughly. Methods of detoxifying the plants are to grind the plant into flour, and then wash it with boiling water, fermenting and heating. Another method was developed by Howard Bradbury and colleagues. The plant is ground into flour and mixed with water. The mixture is then spread thinly (approx. 1 cm) in the shade. It is left there for five to six hours. In this way, almost all of the hydrogen cyanide can outgas .
Since cassava has a low protein content (approx. 2–3% of the dry matter) and very few essential amino acids (risk of kwashiorkor syndrome), we recommend consuming the protein-rich (approx. 30% of the Dry matter) cassava leaves to counteract deficiency symptoms. Since this is not common in many African countries, work is currently being done on a type of cassava that produces provitamin A and other micronutrients in the roots.
Since cassava only contains small amounts of iron and zinc , this leads to deficiency symptoms in people who mainly eat cassava and thus only cover around 10% of their daily requirements for these minerals. By genetically engineering the genes for the iron transporter protein VIT1 and the ferritin protein FER1 from Arabidopsis thaliana, researchers have created a variety that can bind significantly increased amounts of iron and zinc from the soil. In field tests, these plants ingested 7 to 18 times the amount of iron and up to 10 times the amount of zinc
The processing is essentially based on procedures that were practiced by the Indians in the Amazon region, especially for detoxification, and were mentioned by chroniclers as early as the 16th century, such as in 1587 by Gabriel Soares de Sousa in his Tratado descriptivio do Brasil . Traditionally, the tubers are peeled, grated or grated and then soaked. After a few days, the mass is squeezed out, washed through the so-called tipiti and roasted in ovens. The mass that remains in the press provides the manioc or mandioca flour (in Brazilian: farinha ). A by-product of the manufacture of cassava flour is starch, which in Brazil is called polvilho , also known as tapioca . With some (low-glycoside) varieties, there is also the option of boiling the peeled and chopped tubers in salted water, ready to eat.
The flour is processed differently depending on the region. Among other things, it is used to prepare a kind of cake (for example the Brazilian Beiju ), which is more or less similar to bread , or the mandioca flour is mixed with wheat flour, as for example with Conaque in the Antilles . In Brazil, the side dish Farofa and the drink Tarubá are also made from cassava flour. While in Germany under the name of flour , the flour is understood, it is in Brazil, the term farinha synonymous with manioc flour, while wheat flour as farinha de trigo is called.
In most Latin American countries, cassava is also prepared similar to boiled potatoes and served as a side dish. The cassava root can be deep-fried after cooking and then resembles French fries . Cubes of the tuber are also fried in Sudan . A dish that is particularly popular in Peru is yuca á la Huancaína ; Deep- fried yuquitas are available there as a snack at all major fast food chains.
In Africa (especially Cameroon , Gabon and Congo ) the flour is used for a kind of dumpling dough ( fufu ) . The tuber is cooked or fried in steam or water. Getting used to very popular and for European palates are wrapped in palm leaves Maniokstangen that bobolo and Congo Kwanga be mentioned.
The fresh root is also used as a remedy for ulcers . The seeds of some varieties have a laxative and nauseating effect.
Cassava or tapioca can be used as a feed additive for meat production because it is a cheap raw material. Around 25% of the world's cassava production is now used for animal feed. In Africa and Asia this proportion is 17% and 24% respectively, in Latin America 47%. The share of cassava in the compound feed composition of the EU-27 was only 0.5% in 2007. At the beginning of the 1990s the proportion was 6%. In 2007, cassava accounted for just 0.2% of total feed imports.
Renewable raw material
Manioc has great potential for bioethanol production . At present, however, ethanol is only produced from cassava in China and Thailand. The production costs of ethanol are around 0.27 € / l and the ethanol yield is 3.5 to 4 m³ / ha. The achievable fuel yield from cassava in Asia is given as around 78 GJ / ha.
Cassava also plays a role as a starch supplier for the fermentation industry . The cassava starch can be used to manufacture bio-based plastics such as polylactide based on lactic acid , as is planned for example in Thailand . According to estimates by the National Innovation Agency (NIA), this could more than double the market volume of the Thai cassava industry to almost € 3 billion.
The Food and Agriculture Organization (FAO) also sees great potential for the use of cassava as a renewable raw material against the background that current yields are only 20% of the level that can be achieved under optimal conditions. However, the fact that cassava provides around one billion people with up to a third of their daily caloric intake and is therefore an important staple food is likely to prevent further use as a renewable raw material against the background of the discussion about the conflict between food production and industrial use.
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