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Thursday, May 20, 2010

Bolivia nuts

A lots of food from Bolivia is taken for granted; the ubiquitous potato, for instance, was once unknown to the Europeans, but now it is in almost every meal, from fish'n'chips to vichysoise.
But one item in particular from Bolivia not only gets taken for granted, but is named for its large neighbour, even though most of this is harvested in Bolivia; the 'Brazil' nut. Most of this is from the nothern departamentos, where 15,000 tons are harvested each year. (Source: Enciclopedia de Bolivia - ISBN 84-494-1248-8).

It truly is an amazing plant; a tree grows to be 500 years or more. And there is this mysterious symbiosis with an orchid. Orchids, of which Bolivia has quite a few (thousand), are some of my favourite plants. But to think that a tree actually needs one of these is a fantastic construct! Below I have posted a write-up, everything you always wanted to know about 'Brazil' nuts (which are not actually nuts, but the way, so a double mesentendre here...) but were afraid to ask.


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.

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 is currently not economically viable.

The Brazil nut tree's yellow flowers contain very sweet nectar and 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. For this reason, the Brazil nut's reproduction depends on the presence of the orchid Coryanthes vasquezii, which does not grow on the Brazil nut tree itself. 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 do not mate, and therefore the lack of bees means the fruit does not get pollinated.
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 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 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 is not until then that it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.

Despite their name, the most significant exporter of Brazil nuts is not Brazil but Bolivia, where they are called almendras.

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.]

Around 20,000 tons 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.

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.

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, and the nuts are pressed for their oil.

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. 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.

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 lumber 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.

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