Everything about The Brazil Nut totally explained
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 seed.
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.
Tree
The Brazil nut 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. 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.
Reproduction
Brazil nut trees produce fruit almost exclusively in pristine forests, as disturbed forests lack the large-body bees of the genera Bombus, Centris, Epicharis, Eulaema, and Xylocopa which are the only ones capable of
pollinating the tree's flowers. Brazil nuts have been harvested from plantations but production is low and it's currently not economically viable.
This tree has a very sweet nectar in the flower.
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 don't mate, and therefore the lack of bees means the fruit doesn't get pollinated.
If both the orchids and the bees are present, the fruit takes 14 months to mature after pollination of the flowers. The fruit itself 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 (the "Brazil nuts") packed like the segments of an
orange; it isn't 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 it open. 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 isn't until then that it starts growing again.
Capuchin monkeys have been reported to open Brazil nuts using a stone as an
anvil.
Nomenclature
Despite their name, the most significant exporter of Brazil nuts isn't Brazil but Bolivia, where they're 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 the rest of Brazil. And, though it has somewhat 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 was "
nigger toes".
Cream nut is one of several historical names for the Brazil nut used in America.
While cooks classify the Brazil nut as a
nut, botanists consider it to be a
seed and not a nut, since in nuts the shell splits in half with the meat separate from the shell.
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). 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.
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.
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.
Uses
Foodstuff
Brazil nuts are 18%
protein, 13%
carbohydrates, and 69%
fat. The fat breakdown is roughly 25%
saturated, 41%
monounsaturated, and 34%
polyunsaturated. 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. Brazil nuts are very large in size compared to some other nuts. Although often contained in superior nut selections, they're sometimes considered by nut connoisseurs to be less tasty than their nut cousins, such as macadamias, cashews and almonds.
Nutritionally, Brazil nuts are perhaps the richest source of
selenium, containing as much as 1180% of the USRDV, although the amount of selenium varies greatly. They are also a good source of
magnesium and
thiamine. Some research has suggested that selenium intake is correlated with a reduced risk of both
breast cancer as well as
prostate cancer. This has led some commentators to recommend the consumption of Brazil nuts as a protective measure. Subsequent studies about the effects of selenium on prostate cancer are inconclusive.
Ironically the
European Union has imposed strict regulations on the import from Brazil of Brazil nuts in their shells, as the shells have been found to contain high levels of
aflatoxins, which can lead to liver cancer. According to Tony Farndell, MD of TFR Nuts and Dried Fruits Ltd, a UK importer, the situation regarding the import of in-shell kernels came as a result of the whole nut including the shell, being ground down for testing. Thus
aflatoxins were detected and the restrictions imposed.
Other uses
As well as 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 (not to be confused with
Brazilwood) 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.
The
Brazil nut effect, where large items mixed with other smaller items (for example Brazil nuts mixed with
peanuts) tend to rise to the top, is named after the species' large nuts.
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 isn't retained by the body, this is 1,000 times higher than in other foods. According to
Oak Ridge Associated Universities, this isn't because of elevated levels of radium in the soil, but due to "the very extensive root system of the tree."
Further Information
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