Бразилиялық жаңғақтың сипаттамасы мен өсіруі

Species of flowering plant in the family Lecythidaceae

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 and weigh as much as in total. 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.

In Portuguese speaking countries, like Brazil, they are variously called "castanha do brasil" (meaning "chestnuts from Brazil" in Portuguese), "castanha do pará" (meaning "chestnuts from Pará" in Portuguese), with other names: castanha da amazônia, castanha do acre, "noz amazônica" (meaning "Amazonian nut" in Portuguese), noz boliviana, tocari ("probably of Carib origin"), and tururi (from Tupi turu'ri) also used. In North America, as early as 1896, Brazil nuts were sometimes known by the slang term "nigger toes", a vulgarity that fell out of use after the racial slur became socially unacceptable.

The Brazil nut is a large tree, reaching tall, and with a trunk 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. 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, long, and broad. The flowers are small, greenish white, in panicles long; each flower has a two parted, deciduous calyx, six unequal cream colored petals, and numerous stamens united into a broad, hood shaped mass.

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. Brazil nuts have been harvested from plantations, but production is low and is currently not economically viable. The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule in diameter, resembling a coconut endocarp in size and weighing up to It has a hard, woody shell thick, which contains eight to 24 wedge shaped seeds 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. 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.

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. The fruit is heavy and rigid; when the fruits fall, they pose a serious threat to vehicles and potential for traumatic brain injury of people passing under the tree.

Since most of the production for international trade is harvested in the wild, the business arrangement has been advanced as a model for generating income from a tropical forest without destroying it.

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.

Brazil nuts are susceptible to contamination by aflatoxins, produced by fungi, once they fall to the ground. Aflatoxins can cause liver damage, including possible cancer, if consumed. However, mechanical sorting and drying was found to eliminate 98% of aflatoxins; a 2003 EU ban on importation Radium can be concentrated in nuts only if it is present in the soil. Brazil nuts also contain barium, a metal with a chemical behavior quite similar to radium. While barium, if ingested, can have toxic effects, such as weakness, vomiting, or diarrhea, the amount present in Brazil nuts are orders of magnitude too small to have noticeable health effects.

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 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).

The lumber from Brazil nut trees (not to be confused with Brazilwood) is of excellent quality, having diverse uses from flooring to heavy construction. 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. In Brazil, cutting down a Brazil nut tree requires previous authorization from the Brazilian Institute of Environment and Renewable Natural Resources.

Brazil nut oil is used as a lubricant in clocks and in the manufacturing of paint and cosmetics, such as soap and perfume. 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 as jeweler's rouge. The charcoal from the nut shells may be used to purify water.