Brazil nut

From Wikipedia, the free encyclopedia

Brazil nut
Image:Brazil Nut fruit.jpg Brazil nut fruit
Conservation status
Image:Status iucn2.3 VU.svg Vulnerable (IUCN)
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Ericales Family: Lecythidaceae Genus: Bertholletia Species: B. excelsa
Binomial name
Bertholletia excelsa Humb. & Bonpl.

The Brazil nut is a South American tree Bertholletia excelsa in the family Lecythidaceae, and also the name of the tree's commercially harvested edible seeds.

The Brazil nut tree is the only species in the genus Bertholletia. It is native to the Guianas, Venezuela, Brazil, eastern Colombia, eastern Peru and eastern Bolivia. It occurs as scattered trees in large forests on the banks of the Amazon, Rio Negro, and the Orinoco. The genus is named after the French chemist Claude Louis Berthollet.

It is a large tree, reaching 30–45 metres (100–150 ft) tall and 1–2 metres (3–6.5 ft) trunk diameter, among the largest of trees in the Amazon Rainforests. It may live for 500 years or more, and according to some authorities often reaches an age of 1,000 years.^[1]

The stem is straight and commonly unbranched for well over half the tree's height, with a large emergent crown of long branches above the surrounding canopy of other trees. The bark is grayish and smooth.

The leaves are dry-season deciduous, alternate, simple, entire or crenate, oblong, 20–35 centimetre long and 10–15 centimetres broad. The flowers are small, greenish-white, in panicles 5–10 centimetres long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.

Contents 1 Reproduction 2 Nomenclature 3 Nut production 3.1 Effects of harvesting 4 Uses 4.1 Foodstuff 4.2 Other uses 5 Radioactivity 6 See also 7 References and external links

[edit] Reproduction

Image:Question book-3.svg

This section does not cite any references or sources. Please improve this section by adding citations to reliable sources. Unverifiable material may be challenged and removed. (December 2007)

Brazil nuts only produce fruit in virgin forests (forests not previously disturbed by human activity), as forests that are not virgin usually lack an orchid that is indirectly responsible for the pollination of the flowers.^{[citation needed]} The Brazil nut tree's yellow flowers can only be pollinated by an insect strong enough to lift the coiled hood on the flower and with tongues long enough to negotiate the complex coiled flower. The orchids produce a scent that attracts small male long-tongued orchid bees (Euglossa spp), as the male bees need that scent to attract females. The large female long-tongued orchid bee pollinates the Brazil nut tree. Without the orchid, the bees cannot mate, and therefore the lack of bees means the fruit do not get pollinated.

If both the orchids and the bees are present, the fruit takes 14 months to mature after pollination of the flowers, and is a large capsule 10–15 centimetres diameter resembling a coconut endocarp in size and weighing up to 2 kilograms. It has a hard, woody shell 8–12 millimetres thick, and inside contains 8–24 triangular seeds 4–5 centimetres long (Brazil nuts) packed like the segments of an orange; it is not a true nut in the botanical sense.

The capsule contains a small hole at one end, which enables large rodents like the Agouti to gnaw open the capsule. They then eat some of the nuts inside while burying others for later use; some of these are able to germinate to produce new Brazil nut trees. Most of the seeds are "planted" by the Agoutis in shady places, and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it. It is not until then that it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.

[edit] Nomenclature

Despite their name, the most significant exporter of Brazil nuts is not Brazil but Bolivia, where they are called almendras. In Brazil these nuts are called castanhas-do-Pará (literally "chestnuts from Pará"), but Acreans call them castanhas-do-Acre instead. Indigenous names include juvia in the Orinoco area, and sapucaia in Brazil. And, though it has largely fallen into disuse since the latter part of the 20th century, a common slang term for the nuts in some regions of the United States (especially the South) was "Nigger toes".

The cream nut is one of several historical names for the Brazil nut used in America.

While classified by cooks as a nut, botanists consider Brazil nuts to be a seed and not a nut, since in nuts the shell splits in halves, with the meat separate from the shell.

[edit] Nut production

Around 20,000 tonnes of Brazil nuts are harvested each year, of which Bolivia accounts for about 50%, Brazil 40% and Peru 10% (2000 estimates).^[2] In 1980, annual production was around 40,000 tons per year from Brazil alone, and in 1970 Brazil harvested a reported 104,487 tons of nuts.^[3]

[edit] Effects of harvesting

Brazil nuts for international trade come entirely from wild collection rather than from plantations. This has been advanced as a model for generating income from a tropical forest without destroying it. The nuts are gathered by migrant workers known as castanheiros.

Analysis of tree ages in areas that are harvested show that moderate and intense gathering takes so many seeds that not enough are left to replace older trees as they die. Sites with light gathering activities had many young trees, while sites with intense gathering practices had hardly any young trees.^[4]

Statistical tests were done to determine what environmental factors could be contributing to the lack of younger trees. The most consistent effect was found to be the level of gathering activity at a particular site. A computer model predicting the size of trees where people picked all the nuts matched the tree size data that was gathered from physical sites that had heavy harvesting.

[edit] Uses

[edit] Foodstuff

Brazil nuts are 18% protein, 13% carbohydrates, and 69% fat. The fat breakdown is roughly 25% saturated, 41% monounsaturated, and 34% polyunsaturated.^{[citation needed]} They are somewhat earthy in flavor. The saturated fat content of Brazil nuts is among the highest of all nuts, surpassing even macadamia nuts. Because of the resulting rich taste, Brazil nuts can often substitute for macadamia nuts or even coconuts in recipes. Shelled Brazil nuts soon become rancid. The nuts are also pressed for oil.

Nutritionally, Brazil nuts are rich in selenium, although the amount of selenium varies greatly.^[5] They are also a good source of magnesium and thiamine. Some research has suggested that selenium intake is correlated with a reduced risk of prostate cancer.^[6] This has led some commentators to recommend the consumption of Brazil nuts as a protective measure.^[7]. Subsequent studies about the effects of selenium on prostate cancer are inconclusive.^[8]

[edit] Other uses

As well its food use, Brazil nut oil is also used as a lubricant in clocks, for making artists' paints, and in the cosmetics industry.

The timber from Brazil nut trees is of excellent quality, but logging the trees is prohibited by law in all three producing countries (Brazil, Bolivia and Peru). Illegal extraction of timber and land clearances present a continuing threat.^[9]

The Brazil nut effect, where large items mixed with other smaller items (e.g. Brazil nuts mixed with peanuts) tend to rise to the top, is named after the species' large nuts.

[edit] Radioactivity

Brazil nuts contain small amounts of radium, a radioactive material. Although the amount is very small, about 1–7 pCi/g (40–260 Bq/kg), and most of it is not retained by the body, this is 1000 times higher than in other foods. According to Oak Ridge Associated Universities, this is not because of elevated levels of radium in the soil, but due to "the very extensive root system of the tree." ^[10]

[edit] See also

• Official list of endangered flora of Brazil

[edit] References and external links

• Americas Regional Workshop (Conservation & Sustainable Management of Trees, Costa Rica, November 1996) (1998). Bertholletia excelsa. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 09 May 2006. Listed as Vulnerable (VU A1acd+2cd v2.3)
• Peres, C.A. et al. (2003). "Demographic threats to the sustainability of Brazil nut exploitation". Science 302 (Dec. 19): 2112-2114.
• Brazil Nut homepage

• New York Botanical Gardens Brazil Nuts Page
• Brazil nuts' path to preservation, BBC News.
• Brazil nut, The Encyclopedia of Earth
• This article incorporates text from the public domain 1911 edition of The Grocer's Encyclopedia.da:Paranød

de:Paranussbaum es:Bertholletia excelsa fr:Noix du Brésil hsb:Paraworjechowc it:Noce del Brasile he:אגוז ברזילאי lt:Brazilinė bertoletija nl:Paranoot no:Paranøtt pl:Orzesznica wyniosła pt:Castanha-do-pará sl:Brazilski orešček fi:Parapähkinäpuu sv:Paranöt zh:巴西栗