Brazil nut tree
Bertholletia excelsa compose.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Lecythidaceae
Subfamily: Lecythidoideae
Genus: Bertholletia
Bonpl.
Species:
B. excelsa
Binomial name
Bertholletia excelsa
Humb. & Bonpl.

The Brazil nut (Bertholletia excelsa) is a South American tree in the family Lecythidaceae, and it is also the name of the tree's commercially harvested edible seeds. It is one of the largest and longest-lived trees in the Amazon rainforest. The fruit and its nutshell – containing the edible Brazil nut – are relatively large, possibly weighing as much as 2 kg (4 lb 7 oz) in total weight. As food, Brazil nuts are notable for diverse content of micronutrients, especially a high amount of selenium. The wood of the Brazil nut tree is prized for its quality in carpentry, flooring, and heavy construction.[1]

Common names

Brazil nut seeds in shell
Brazil nut seeds in shell
Depiction of the Brazil nut in Scientific American Supplement, No. 598, June 18, 1887
Depiction of the Brazil nut in Scientific American Supplement, No. 598, June 18, 1887

In various Spanish-speaking countries of South America, Brazil nuts are called castañas de Brasil, nuez de Brasil, or castañas de Pará (or Para).[1][2] In Brazil, they are more commonly called "castanha-do-pará" (meaning "chestnuts from Pará" in Portuguese), with other names also used.[1]

In North America, as early as 1896, Brazil nuts were sometimes known by the slang term "nigger toes",[3][4][5] a vulgarity that gradually fell out of use as the racial slur became socially unacceptable.[6][7]

Taxonomy

The Brazil nut family, the Lecythidaceae, is in the order Ericales, as are other well-known plants such as blueberries, cranberries, sapote, gutta-percha, tea, phlox, and persimmons. The tree is the only species in the monotypic genus Bertholletia,[1] named after French chemist Claude Louis Berthollet.[8]

Description

Tree branch
Tree branch

The Brazil nut is a large tree, reaching 50 m (160 ft) tall,[9] and with a trunk 1 to 2 m (3 ft 3 in to 6 ft 7 in) in diameter, making it among the largest of trees in the Amazon rainforest. It may live for 500 years or more, and can often reach a thousand years of age.[10] The stem is straight and commonly without branches 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 cm (8–14 in) long, and 10–15 cm (4–6 in) broad. The flowers are small, greenish-white, in panicles 5–10 cm (2–4 in) long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.[citation needed]

Range

The Brazil nut 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 River, Rio Negro, Tapajós, and the Orinoco.

As a result, they can be found outside production areas, in the backyards of homes and near roads and streets in the Northern and Northeastern Brazil.[citation needed] The fruit is heavy and rigid; when the fruits fall, they pose a serious threat to vehicles and people passing under the tree.

Reproduction

A freshly cut Brazil nut fruit
A freshly cut Brazil nut fruit

Brazil nut trees produce fruit almost exclusively in pristine forests, as disturbed forests lack the large-bodied bees of the genera Bombus, Centris, Epicharis, Eulaema, and Xylocopa, which are the only ones capable of pollinating the tree's flowers, with different bee genera being the primary pollinators in different areas, and different times of year.[11][12][13] Brazil nuts have been harvested from plantations, but production is low and is currently not economically viable.[9][14][15]

The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule 10–15 cm (4–6 in) in diameter, resembling a coconut endocarp in size and weighing up to 2 kg (4 lb 7 oz). It has a hard, woody shell 8–12 mm (3812 in) thick, which contains eight to 24 wedge-shaped seeds 4–5 cm (1+58–2 in) long (the "Brazil nuts") packed like the segments of an orange, but not limited to one whorl of segments. Up to three whorls can be stacked onto each other, with the polar ends of the segments of the middle whorl nestling into the upper and lower whorls (see illustration above).

The capsule contains a small hole at one end, which enables large rodents like the agouti to gnaw it open.[16] They then eat some of the seeds inside while burying others for later use; some of these are able to germinate into new Brazil nut trees.[16] Most of the seeds are "planted" by the agoutis in caches during wet season,[16] and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it, when it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.

Society and culture

In Brazil, cutting down a Brazil nut tree (typically with the intent of harvesting lumber and Brazil nuts) is illegal, unless done with previous authorization from the Brazilian Institute of Environment and Renewable Natural Resources.[17][18]

Production

Brazil nut production – 2020
Country (tonnes)
 Brazil 33,118
 Bolivia 30,843
 Peru 5,697
World 69,658
Source: FAOSTAT of the United Nations[19]

In 2020, global production of Brazil nuts (in shells) was 69,658 tonnes, most of which derive from wild harvests in tropical forests, especially the Amazon regions of Brazil and Bolivia which produced 92% of the world total (table).

Environmental effects of harvesting

Since most of the production for international trade is harvested in the wild,[20][21] the business arrangement has been advanced as a model for generating income from a tropical forest without destroying it.[20] The nuts are most often gathered by migrant workers known as castañeros (in Spanish) or castanheiros (in Portuguese).[20] Logging is a significant threat to the sustainability of the Brazil nut-harvesting industry.[20][21]

Analysis of tree ages in areas that are harvested shows that moderate and intense gathering takes so many seeds that not enough are left to replace older trees as they die.[21] Sites with light gathering activities had many young trees, while sites with intense gathering practices had nearly none.[22]

European Union import regulation

In 2003, the European Union imposed strict regulations on the import of Brazilian-harvested Brazil nuts in their shells, as the shells are considered to contain unsafe levels of aflatoxins, a potential cause of liver cancer.[23]

Nutrition and human consumption

Brazil nuts, dried, unblanched, shelled
Nutritional value per 100 g (3.5 oz)
Energy2,743 kJ (656 kcal)
12.27 g
Starch0.25 g
Sugars2.33 g
Dietary fiber7.5 g
66.43 g
Saturated15.137 g
Monounsaturated24.548 g
Polyunsaturated20.577 g
14.32 g
Tryptophan0.141 g
Threonine0.362 g
Isoleucine0.516 g
Leucine1.155 g
Lysine0.492 g
Methionine1.008 g
Phenylalanine0.630 g
Tyrosine0.420 g
Valine0.756 g
Arginine2.148 g
Histidine0.386 g
Alanine0.577 g
Aspartic acid1.346 g
Glutamic acid3.147 g
Glycine0.718 g
Proline0.657 g
Serine0.683 g
VitaminsQuantity
%DV
Thiamine (B1)
54%
0.617 mg
Riboflavin (B2)
3%
0.035 mg
Niacin (B3)
2%
0.295 mg
Vitamin B6
8%
0.101 mg
Folate (B9)
6%
22 μg
Vitamin C
1%
0.7 mg
Vitamin E
38%
5.73 mg
MineralsQuantity
%DV
Calcium
16%
160 mg
Iron
19%
2.43 mg
Magnesium
106%
376 mg
Manganese
57%
1.2 mg
Phosphorus
104%
725 mg
Potassium
14%
659 mg
Sodium
0%
3 mg
Zinc
43%
4.06 mg
Other constituentsQuantity
Water3.48 g
Selenium1917 μg
Beta-Sitosterol64 mg

Percentages are roughly approximated using US recommendations for adults.
Source: USDA FoodData Central
Brazil nuts after shell removal
Brazil nuts after shell removal

Brazil nuts are 3% water, 14% protein, 12% carbohydrates, and 66% fats (table). The fat components are 16% saturated, 24% monounsaturated, and 24% polyunsaturated (see table for USDA source).

In a 100 gram (3.5 oz) reference amount, Brazil nuts supply 659 calories, and are a rich source (20% or more of the Daily Value, DV) of dietary fiber (30% DV), thiamin (54% DV), vitamin E (38% DV), magnesium (106% DV), phosphorus (104% DV), manganese (57% DV), and zinc (43% DV). Calcium, iron, and potassium are present in moderate amounts (10-19% DV, table).

Selenium

See also: Selenium § Toxicity

Brazil nuts are a particularly rich source of selenium, with just 28 g (1 oz) supplying 544 micrograms of selenium or 10 times the DV of 55 micrograms (see table for USDA source).[24] However, the amount of selenium within batches of nuts may vary considerably.[25]

The high selenium content is used as a biomarker in studies of selenium intake and deficiency.[26][27] Consumption of just one Brazil nut per day over 8 weeks was sufficient to restore selenium blood levels and increase HDL cholesterol in obese women.[27]

Phytochemicals

Brazil nuts are susceptible to contamination by aflatoxins, produced by fungi, once they fall to the ground.[28] Aflatoxins can cause liver damage, including possible cancer, if consumed.[23] Aflatoxin levels have been found in Brazil nuts during inspections that were far higher than the limits set by the EU.[29] However, mechanical sorting and drying was found to eliminate 98% of aflatoxins; a 2003 EU ban on importation[23] was rescinded after new tolerance levels were set.

The nuts often contain radium, a radioactive element, with a kilogram of nuts containing an activity between 40 and 260 becquerels (1 and 7 nanocuries). This level of radium is small, although it can be about 1,000 times higher than in other common foods. According to Oak Ridge Associated Universities, elevated levels of radium in the soil does not directly cause the concentration of radium, but "the very extensive root system of the tree" can concentrate naturally occurring radioactive material, when present in the soil.[30] Radium can be concentrated in nuts only if it is present in the soil.[31]

Brazil nuts also contain barium, a metal with a chemical behavior quite similar to radium,[32] which, if ingested, can have toxic effects, such as weakness, vomiting or diarrhea.[33]

Uses

Oil

Brazil nut oil
Brazil nut oil

Brazil nut oil contains 48% unsaturated fatty acids composed mainly of oleic and linoleic acids, the phytosterol, beta-sitosterol,[34] and fat-soluble vitamin E.[35]

The following table presents the composition of fatty acids in Brazil nut oil (see USDA source in nutrition table):

Palmitic acid 10%
Palmitoleic acid 0.2%
Stearic acid 6%
Oleic acid 24%
Linoleic acid 24%
Alpha-linolenic acid 0.04%
Saturated fats 16%
Unsaturated fats 48%

Wood

A Brazil nut tree (Castanheira)
A Brazil nut tree (Castanheira)

The lumber from Brazil nut trees (not to be confused with Brazilwood) is of excellent quality, having diverse uses from flooring to heavy construction.[1] Logging the trees is prohibited by law in all three producing countries (Brazil, Bolivia, and Peru). Illegal extraction of timber and land clearances present continuing threats.[36]

Other uses

A carved Brazil nut fruit
A carved Brazil nut fruit

Brazil nut oil is used as a lubricant in clocks, in the manufacturing of paint, and in the cosmetics industry.[37] Because of its hardness, the Brazil nutshell is often pulverized and used as an abrasive to polish materials such as metals and ceramics, in the same way jeweler's rouge is used.

See also

References

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  2. ^ PROYECTO PARA DECLARACIÓN DE ALÉRGENOS y SUSTANCIAS QUE PRODUCEN REACCIONES ADVERSAS EN LOS RÓTULOS DE LOS ALIMENTOS, CUALQUIERA SEA SU ORIGEN, ENVASADOS EN AUSENCIA DEL CLIENTE, LISTOS PARA SER OFRECIDOS AL CONSUMIDOR (DEC. 117/006 DEL RBN) (PDF) (Report). Argentine government. n.d. p. 3.
  3. ^ Lyons, A. B. (2015) Plant Names, Scientific and Popular, 2nd edition. Arkose Press. p. 71. ISBN 978-1345211849
  4. ^ Young, W. J. (1911). "The Brazil Nut". Botanical Gazette. 52 (3): 226–231. doi:10.1086/330613.
  5. ^ ""Nigger", noun and adjective". Oxford English Dictionary. 2019. Retrieved November 29, 2019.
  6. ^ Essig, Laurie (July 12, 2016). "White Like Me, Nice Like Me". Psychology Today. Retrieved November 29, 2019.
  7. ^ Brunvand, J. H. (1972). "The Study of Contemporary Folklore: Jokes". Fabula. 13 (1): 1–19. doi:10.1515/fabl.1972.13.1.1. S2CID 162318582.
  8. ^ Burkhardt, Lotte (2022). Eine Enzyklopädie zu eponymischen Pflanzennamen [Encyclopedia of eponymic plant names] (pdf) (in German). Berlin: Botanic Garden and Botanical Museum, Freie Universität Berlin. doi:10.3372/epolist2022. ISBN 978-3-946292-41-8. S2CID 246307410. Retrieved January 27, 2022.
  9. ^ a b Hennessey, Tim (March 2, 2001). "The Brazil Nut (Bertholletia excelsa)". Archived from the original on January 11, 2009. Retrieved July 17, 2012.
  10. ^ Taitson, Bruno (January 18, 2007). "Harvesting nuts, improving lives in Brazil". World Wildlife Fund. Archived from the original on May 23, 2008. Retrieved July 17, 2012.
  11. ^ Nelson, B. W.; Absy, M. L.; Barbosa, E. M.; Prance, G. T. (1985). "Observations on flower visitors to Bertholletia excelsa H. B. K. and Couratari tenuicarpa A. C. Sm.(Lecythidaceae)". Acta Amazonica. 15 (1): 225–234. doi:10.1590/1809-43921985155234. Retrieved April 8, 2008.[permanent dead link]
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  17. ^ Moncrieff, Virginia M. (September 21, 2015). "A little logging may go a long way". Forest News. Center for International Forestry Research. Retrieved July 8, 2020 – via CIFOR.org.
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  19. ^ "Brazil nut production in 2020; Crops/Regions/World list/Production Quantity (pick lists)". UN Food and Agriculture Organization, Corporate Statistical Database (FAOSTAT). 2020. Retrieved May 17, 2022.
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  28. ^ "Aflatoxins in food". European Food Safety Authority. March 1, 2007.
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  30. ^ "Brazil Nuts". Oak Ridge Associated Universities. January 20, 2009. Archived from the original on October 6, 2021. Retrieved December 17, 2018.
  31. ^ Adams, Rod (January 4, 2014). "BBC Bang Goes the Theory demonstrates that NOT all Brazil nuts are radioactive". Atomic Insights. Retrieved May 18, 2021.
  32. ^ "Brazil Nuts". Museum of Radiation and Radioactivity. Retrieved October 6, 2021.
  33. ^ "Biomonitoring Summary". www.cdc.gov. September 3, 2021. Retrieved October 6, 2021.
  34. ^ Kornsteiner-Krenn, Margit; Wagner, Karl-Heinz; Elmadfa, Ibrahim (2013). "Phytosterol content and fatty acid pattern of ten different nut types". International Journal for Vitamin and Nutrition Research. 83 (5): 263–270. doi:10.1024/0300-9831/a000168. PMID 25305221.
  35. ^ Ryan, E.; Galvin, K.; O'Connor, T. P.; Maguire, A. R.; O'Brien, N. M. (2006). "Fatty acid profile, tocopherol, squalene and phytosterol content of brazil, pecan, pine, pistachio and cashew nuts". International Journal of Food Sciences and Nutrition. 57 (3–4): 219–228. doi:10.1080/09637480600768077. PMID 17127473. S2CID 22030871.
  36. ^ "Greenpeace Activists Trapped by Loggers in Amazon". Greenpeace. October 18, 2007. Retrieved July 17, 2012.
  37. ^ K, Lim T. (2012). Edible Medicinal And Non Medicinal Plants: Volume 3, Fruits. Springer Science & Business Media. ISBN 978-94-007-2534-8.