Rabu, 09 Juni 2010

Brazil nut

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

The Brazil nut family is in the order Ericales, as are other well known plants such as: blueberries, cranberries, sapote, gutta-percha, tea, kiwi fruit, phlox, and persimmons.

The Brazil nut tree is the only species in the monotypic type 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.

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.

Nutrition
Brazil nuts are 18% protein, 13% carbohydrates, and 69% fat. The fat breakdown is roughly 25% saturated, 41% monounsaturated, and 34% polyunsaturated. The saturated content of Brazil nuts is among the highest of all nuts, surpassing macadamia nuts, which are primarily monounsaturated fat [citation needed], and the nuts are pressed for their oil. Because of the resulting rich taste, Brazil nuts can often substitute for macadamia nuts or even coconut in recipes. Also due to their high polyunsaturated fat content, primarily omega-6, shelled Brazil nuts soon become rancid.

Nutritionally, Brazil nuts are a good source of magnesium and thiamine, and are perhaps the richest dietary source of selenium; one ounce can contain as much as 10 times the adult USRDA (U.S. Recommended Dietary Allowances), more even than the Tolerable Upper Intake Level (UL), although the amount of selenium within batches of nuts varies greatly. Recent research suggests that proper selenium intake is correlated with a reduced risk of both breast cancer as well as prostate cancer. This has led some health commentators and nutritionists to recommend the consumption of Brazil nuts as a protective measure. These findings are inconclusive, however; other investigations into the effects of selenium on prostate cancer were inconclusive.

Brazil nuts have one of the highest concentrations of phytic acid at 2 to 6% of dry weight. (Phytic acid can prevent absorption of some nutrients.)

Despite the possible health benefits of the nut, 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 import restrictions on 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.

Brazil nuts also contain small amounts of radioactive radium. Although the amount of radium is very small, about 1–7 pCi/g (40–260 Bq/kg), and most of it is not retained by the body, this is 1,000 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."

Source: http://en.wikipedia.org/wiki/Brazil_Nut
See Also: Online flowers ordering, international flower delivery, online flower shop

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