Cashew

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Cashew
Cashew tree (A. occidentale), illustration from Koehler 1887

Cashew tree ( A. occidentale ), illustration from Koehler 1887

Systematics
Eurosiden II
Order : Sapindales (Sapindales)
Family : Sumac family (Anacardiaceae)
Subfamily : Anacardioideae
Genre : Anacardium
Type : Cashew
Scientific name
Anacardium occidentale
L.
Cashew tree
ripe fruits

The cashew tree ( listening ? / I ; Latin Anacardium occidentale ), also known as the cashew tree , cashew tree or kidney tree, is a tree belonging to the sumac family (Anacardiaceae). It grows in tropical climates and carries cashew apples and cashew nuts. The Portuguese were the first Europeans to discover this tree in northeastern Brazil . The name cashew is derived from the Portuguese name Caju or Cajueiro from the Indian Tupi language Acaju , kidney tree (probably because of the shape of the kernels). Audio file / audio sample

description

Vegetative characteristics

The cashew tree is a fast-growing, drought-resistant, evergreen , andromonozoan deciduous tree that reaches heights of growth of 10-12 m or higher and a diameter of about 30-40 cm at breast height . Its sweeping crown is intensely branched and more or less symmetrical, but can take on irregular shapes in wind-exposed locations. In addition to tap roots reaching 1–2 m deep, the tree also develops a relatively extensive system of lateral roots . This ability, combined with a certain tolerance to nutrient poverty and occasional drought, means that the tree is well suited as a wind and erosion protection. The bark develops into a brown, rough and deeply furrowed bark with age. The trunk contains a gum (cashew, cashew gum).

The alternate, obovate, leathery and bare leaves are about 8–15 × 6–13 cm in size. The leaves have entire margins and are rounded to blunt, sometimes with margins to indented, the leaf base is wedge-shaped or pointed to blunt. The nerve is alternately pinnate.

Generative characteristics

The long-stalked, paniculate and fine-haired, mixed inflorescences are up to 20-25 cm long, the smaller male or hermaphrodite five-fold flowers are sessile to short-stalked. There are lanceolate bracts on the flowers . The egg-shaped and pointed sepals are hairy. The five bent back petals are linear-lanceolate and white, greenish to reddish. They are fine-haired on the outside and only slightly hairy on the inside. There are 7–10 (14) stamens , there is only one fertile, very long and protruding stamen, the male flowers are longer. The other, shorter stamens are sterile. The round ovary in the hermaphrodite flowers is on top with a long, laterally attached and protruding style with a heady stigma. Male flowers have only one stunted ovary. There are extra-floral and floral nectaries . Pollination takes place by bees , flies and ants , but also by the wind .

The number of chromosomes is 2n = 40, less often 24.

Use of the cashew tree

Cashew fruit and cashew apple

The cashew fruit, a solitary stone fruit or, according to another view, a nut , is a small, about 2–2.5 × 1.5 cm, greenish to brownish, kidney or boxing glove-shaped structure that hangs from a fleshy, thickened fruit stem. This kidney-shaped cashew fruit is harvested and the well-known cashew kernel is extracted from it (see cashew kernels below ).

The approximately 5–10 cm long, pear or paprika-shaped, thickened fruit stalk is known as the "cashew apple". As a fruit stalk (hypocarp), the cashew apple is a dummy fruit and not the actual fertile fruit of the cashew tree. When ripe it is yellow, orange to red in color and develops an intense, fruity-sweet scent. He is very intense flavor, sweet-sour, a little apple-like and it contains a lot of vitamin C . The juice of the raw false fruit is colorless and transparent, but when it dries it causes deep black, mostly indelible stains on almost all materials. The cashew apple is easily perishable and its outer skin is very sensitive to pressure. For this reason, it is difficult to transport and cannot be traded internationally. It is therefore processed further immediately after the harvest.

The cashew apple is processed into cashew juice and jam ( jam ). In Brazil, cashew apples are used to make a drink called cajuína, which is said to have medicinal and ritual properties. In Goa , India , the juice is also used to make schnapps, known as cashew feni .

Cashew shell oil

Cashew shell oil is extracted from the middle part of the pericarp of the cashew fruit (mesocarp). The toxic oil is irritating to the skin. It is used industrially and medically. It is said to protect wood and paper from termite damage and worm infestation, for example also on wooden boats, fishing nets and also on warts and corns. Furthermore, a heat-resistant rubber and technical resins are produced from the oil by polymerization .

The oil consists of about 82% anacardic acid , a mixture of 6-nC 15 -alkylsalicylic acids, the side chains of which are saturated, mono-, di- or triolefinic, about 16.5% cardol (pentadecadienylresorcinol, strongly skin-irritating phenol derivative) and 2-methylcardol , and traces of gallic acid and glucosides . The technical Kaschuschalenöl contains primarily the decarboxylation of anacardic acid which cardanol (= Anacardol) and cardol.

Anacardic acid, the main component of the shell oil is reacted by heating to cardanol, which, for example, to Phenalkaminen implemented, as the hardener for epoxy resin is used. The result is a particularly elastic resin that is insensitive to water when it hardens. It is used, for example, as a paint for seagoing ships, pipelines and concrete floors.

Cashew nuts

Salted cashew nuts

The cashew fruit is also called "elephant louse" and contains the kernels (seeds) that are traded as cashews or cashew nuts in German-speaking countries with the English name cashew .

The kernels are sold raw, roasted and salted, caramelized or seasoned. Their taste is sweet and nutty and less intense than that of peanuts or walnuts . A vegetable oil can also be pressed from them (cashew oil, cashew oil).

The kernels mainly contain fatty oil ( cashew oil ), average oil content: 45.6%. The main fatty acids are: oleic acid (73.7%), linoleic acid (14.3%), palmitic acid (7.5%) and stearic acid (4.5%). 96% of the fats are present as triglycerides and 4% as glyco- and phospholipids . Proteins make up about 20% and carbohydrates about 27% (starch about 12%) of the kernels.

Cashew nuts are a good source of minerals, such as magnesium, which plays an important role in strengthening bones and the activity of enzymes. The nuclei also contain iron, which is an important part of hemoglobin , an essential part of red blood cells.

Nutritional values ​​of the kernels

(The information relates to 100 g of seeds, dry-roasted, without salt.)

particularities

In hardly any other food is the proportion of the essential amino acid tryptophan as high as in cashew nuts. Tryptophan is an essential nutrient in the production of the neurotransmitter serotonin . Together with vitamin B6 ( brewer's yeast , potatoes ) tryptophan can help treat depression .

Commercially available raw kernels are not really raw in every case, and steam treatment is usually not specified.

Some people are allergic to cashew nuts, but this allergy is rare.

Cultivation

Worldwide cashew production (2000)

The cashew tree is native to Brazil . In the 16th century it was introduced to Mozambique and India by the Portuguese to counteract erosion on the coasts. In the 19th century, cultivation in plantations appeared and spread to other countries in Africa, Asia and Latin America. Since the beginning of the 20th century, India became the center of the (mostly manual) processing of cashew nuts, which were also exported to America and Europe from there. From the 1960s onwards, cashew products from East Africa were largely exported to India and processed there.

In the 1970s, African countries, especially Mozambique and Tanzania , produced the majority of cashew nuts. Meanwhile, production in India has increased, and it has also expanded in Asian countries such as Indonesia and Vietnam in the 1990s. According to a 2016 report, Vietnam, Nigeria, India, and Ivory Coast are the largest producers. The smaller West African states of Ivory Coast , Benin and Guinea-Bissau have also expanded cashew cultivation. In Ghana we have also succeeded in promoting further processing. In the West African countries, cultivation is supported by the Competitive Cashew Initiative (ComCashew) in order to make the sector there competitive and to secure the income of the farmers.

In Guinea-Bissau, the government promoted the cultivation of cashew nuts as cash crops . It set minimum prices and encouraged farmers to plant cashews and use the proceeds to buy rice, a staple food. When world market prices fell in 2006, Indian wholesalers either stopped buying cashew nuts from Guinea-Bissau or bought them at correspondingly lower prices. This led to hunger among parts of the population.

Economical meaning

In 2018, according to the food and agriculture organization FAO, 5,932,507 t of cashew nuts (with shell) were harvested worldwide. The largest producer was Vietnam, which alone brought in almost 45% of the harvest. Almost 66% of the world's harvest was produced on the entire Asian continent, and around 31% in Africa.

The following table gives an overview of the ten largest producers of cashew nuts worldwide, who harvested 90.2% of the total.

Largest cashew producers (2018)
rank country Quantity
(in t )
1 VietnamVietnam Vietnam 2,663,885
2 IndiaIndia India 785.925
3 Ivory CoastIvory Coast Ivory Coast 688,000
4th PhilippinesPhilippines Philippines 228.612
5 BeninBenin Benin 215.232
6th TanzaniaTanzania Tanzania 171,455
7th MaliMali Mali 150.934
8th Guinea-BissauGuinea-Bissau Guinea-Bissau 167,621
9 BrazilBrazil Brazil 141,418
10 IndonesiaIndonesia Indonesia 136.402
Top ten 5,349,484
other producers 583.023

Trivia

The largest cashew tree in the world is in the Brazilian state of Rio Grande do Norte in the city of Parnamirim .

photos

  • Trunk of the cashew tree

  • Cashew fruit

  • Cashew fruit: below the red cashew apple (fruit stalk), above the fruit.

  • Cashew fruit (in Bali); Indonesian name for the seed (cashew nut): kacang mete

  • Blossoms of the cashew tree

literature

Web links

Commons : Cashew  album with pictures, videos and audio files

Individual evidence

  1. ^ A b Heinz A. Hoppe: Drug Science. Volume 1: Angiosperms , 8th edition, De Gruyter, 1975, ISBN 3-11-003849-8 , p. 73.
  2. ↑ W. Wunnachit, CF Jenner, M. Sedgley: Floral and Extrafloral Nectar Production in Anacardium occidentale L. (Anacardiaceae): An Andromonoecious Species. In: International Journal of Plant Sciences. Vol. 153, no. 3, Part 1, 1992, pp. 413-420, doi : 10.1086 / 297046 , (PDF; 1.3 MB).
  3. ↑ W. Wunnachit: Floral biology of cashew (Anacardium occidentale L.) in relation to Pollination and Fruit set. 1991, online (PDF, 6.6 MB), at digital.library.adelaide.edu.au, accessed on February 19, 2018.
  4. ↑ DK Salunkhe, SS Kadam: Handbook of Fruit Science and Technology. Marcel Dekker, 1995, ISBN 0-8247-9643-8 , p. 26.
  5. ^ Anacardium occidentale at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis.
  6. ^ A b Rudolf Hansel, Konstantin Keller, Horst Rimpler, Gerhard Schneider: Drugs AD . Springer-Verlag, 2013, ISBN 978-3-642-58087-1 , pp. 258 ( limited preview in Google Book search).
  7. ↑ Alexander H. Tullo: A Nutty Chemical. In: Chemical & Engineering News . 86 (36), 2008, pp. 26-27, doi : 10.1021 / cen-v086n036.p026 .
  8. ↑ Nutritional values ​​of cashew nuts on aboutnuts.com.
  9. ↑ Nuts, cashew nuts, dry roasted, without salt added. at USDA National Agricultural Library.
  10. ↑ Tryptophan occurrence in the cashew nut ( Memento from February 21, 2014 in the Internet Archive ).
  11. ↑ a b FAO : Small-scale cashew nut processing (PDF) 2004.
  12. ^ Klaus von Freyhold: The cashew sector in Ghana. In: Hans-Heinrich Bass (Ed.): Promoting the Production of Cashew, Shea, and Indigenous Fruits in West Africa. ITD Annual Report Supplement 2 , 2013, pp. 13–18, urn : nbn: de: 0168-ssoar-338461 .
  13. ^ German Society for International Cooperation (GIZ) GmbH: Competitive Cashew Initiative (ComCashew). In: giz.de. Retrieved January 18, 2017 .
  14. ↑ Jochen Faget: Struggle for survival. In: Deutschlandfunk , September 20, 2006, accessed on October 18, 2015.
  15. ↑ a b Crops> Cashew nuts, with shell. In: Official FAO production statistics for 2018. fao.org, accessed on April 10, 2020 .