Brasil nuts - Castaña de monte
Nuez del Brasil- Nuez amazonica
(Bertholletia excelsa)
 

 
arbol de almendras
castaña

Brazil nut tree

Triangular seeds 4–5 centimetres long

 
 
brazilnuts
brasilnuts

they are called almendras.

Brazil nut seeds

 
 
Aceite brasilnuts
 

BRAZIL NUT
BERTHOLLETIA EXCELSA

Brazil nuts, or Castana, are produced by a large tropical forest tree (Bertholletia excelsa and B. nobilis), Lecythidacea family, that grows throughout the Amazon Basin. Brazil nut is an angular nut with a very hard hull. The almond is very white, with dark brown tegument. A tree may produce more than 150 kg of nuts/year. The species is propagated naturally. The fruit is mature in November but only harvested from wild trees in January. Amazonians prefer to wait until the nuts fall because it seems that the quality of the almond is better then. As the trees are very high, gathering is always dangerous since the fruits weigh approximately 3 kg.

Bolivia, Brazil and Peru produce all of the 20 000 t of Brazil nuts sold on the world market. Bolivia is the top producer, with 10 000 t, and the other half of the production is shared between Peru 2 200 t and Brazil 7 800 t (Collinson et al., 2000). Bolivia is also the top exporting country, accounting for 75% of the sales. Brazil nuts are generally marketed in their hulls or peeled and consumed raw, roasted, salted, mixed with dairy ice creams, in chocolates, pastry and confectionery products. They are an important source of income for local people.

Because of its high selenium content, i.e. up to 30 µg/g, this nut is considered to be a beneficial anti-radicalizing or anti-cancer product. Brazil nuts compete with many other nuts on the world market (Table I). Hazelnuts, groundnuts, almonds and cashew nuts dominate the market, followed by coconut, walnuts and pecan nuts. Brazil nut is thus a minor player on the world market, accounting for only 1.62% of the overall trade volume.

Although there is a considerable amount of descriptive literature available on the Brazil nut tree and fruit, little has been written about the biochemical composition of the nut and its nutritional benefits.

The goal of this study was to gain further insight into the biochemical composition of Brazil nuts, particularly concerning minerals, oil, proteins and carbohydrate fractions.

Components
Brazil nut cake
Whole Brazil nut/ (*calculated)
Ash
7.0
2.0*
Selenium (ppm)
126
40*
Oil
5.0
72.5
Unsaturated fatty acids (% of oil)
75.6
75.6
Sterols (mg/g)
1.4
Tocopherols (mg/g)
0.2
Phospholipids (µg P/g oil)
377
Peroxyde Index
9.8
Acidity
0.6
Density
0.975
Unsaponifiable (% of oil)
0.7
Protein
67.9
19.7*
Fibers
13.0
3.8*
Soluble sugars
7.1
2.1*
Glucose
0.2
Fructose
1.0
Sucrose
5.9

Carbohydrates

The total sugar content (glucose + fructose + sucrose) of Brazil nut defatted cake was 7.1%. By taking into account the water and oil contents, the sugar content of whole nuts was 2.1% (Table II). This content is equivalent to that of pecan nuts (2.1%), macadamia (4.2%), almond (3.6%) (Fourie, Basson, 1990), but lower than that of sunflower cake (6.3%) (Vioque et al., 2000).


Elements and nutritionalvalue

Fatty acids

The distinction between saturated, mono-unsaturated or poly-unsaturated corresponds to the presence of zero, one or more double bonds or “unsaturations” in the fatty acid (FA) structure. In nature, all fatty substances contain the three types of FA in variable amounts. A saturated lipid mainly but not exclusively consists of saturated FA. Certain fatty acids are known to be “essential”, because the human body cannot synthesize them alone. It must thus obtain them from food or supplements. These poly-unsaturated FA are involved in important processes such as the constitution and integrity of cellular membranes, operations of the cardiovascular system, brain and hormonal system, as well as regulation of inflammatory processes.

Essential FA belong to omega-3 and omega-6 families. In the ω-3 family, alpha linolenic acid (C18:3) is essential. It should represent about 1% of ingested energy, i.e. 1-2 g/day. In the ω-6 family, linoleic acid (C18:2) is essential. It should represent 4-16 g/day, depending on the authors.

Sterols

Sterols are naturally occurring substances found in plants. Plant sterols, called phytosterols, which occur in oils may reduce blood cholesterol levels. Phytosterols are similar in structure to cholesterol but are not produced by the human body. Phytosterols can reduce total cholesterol and LDL cholesterol. Reducing total and LDL could contribute to the prevention of cardiovascular disease.

Tocopherols

Four tocopherols and four tocotrienols (α, β, γ, δ) are classified with vitamin E. They are minor but predominant components in cellular membranes. Their primary task is to prevent damage caused by free radicals on tissues by giving a hydrogen atom to a peroxyde radical resulting from unsaturated lipid degradation. Dietary vitamin E supplementation is associated with a reduction in cardiovascular diseases. The basic structure of tocopherols includes two cycles and a C16 side chain. In tocopherols, this side chain is saturated and it contains three double bonds in tocotrienols. Anti-oxidant activity decreases from α to δ tocopherols. Tocotrienols are the most effective anti-oxidants because of their unsaturation. The daily recommended intake is 3-15 mg.

Amino acids

Amino acids (AA) are the molecular units that make proteins. All of them have a COOH group and an amino or amido group. All proteins have various compositions of twenty specific naturally occurring amino acids. Among them, eight are considered critical because they are not synthesized by humans. The daily recommended protein intake is around 0.7 g/kg body mass. A quality index has been established by FAO/WHO. It is based on the ability of a protein to supply essential AA relative to estimated human needs. Reference profiles (mg AA/g protein) have been proposed to define the needs of each AA. These needs are periodically revised. For instance, in 1991, FAO/WHO proposed: lysine, 58; sulfured amino acids, 25; threonin, 34; tryptophane, 11.

Minerals

Minerals are essential to life. They represent 4% of the body mass. The recommended daily intake of calcium is 600-1 000 mg. It is one of the major constituents of bones, but it also intervenes in blood coagulation, body and cardiac muscle contraction. Magnesium is involved in numerous cell biology phenomena. It should be ingested at a 1:2 ratio with calcium in order to be efficient. The recommended daily intake of magnesium is around 300 mg. The recommended daily intake of phosphorus is around 1 000 mg. It is involved in the constitution of bones and teeth.

Selenium

Selenium belongs to the oligoelement category. The principal functions of selenium in the body were summarized by Dr. Clarke of Arizona University (http://www.selenium.arizona.edu/). Selenium is found in the active site of many enzymes such as thioredoxin reductase, which catalyzes oxidation/reduction reactions. Glutathion peroxidase, an enzyme that helps to prevent the oxidation process, needs selenium for its formation. Selenium seems to improve the immune system and its response to infections. There are indications that it supports the natural death of cells, which destroys infectious bacteria. P450 enzymes, which help to detoxify some pro-cancerous substances, can be induced by selenium. Selenium inhibits the action of prostaglandins which are responsible for inflammatory reactions in the body. Male fertility can be increased by selenium, which improves spermatozoid mobility. At high amounts, selenium can decrease the growth rate of the tumoral cells.

The United States National Research Council suggests a human requirement of approximately 60-120 µg Se/day with toxicity occurring after prolonged ingestion of 2 400-3 000 µg Se/day (Food and Nutrition Board, 1976). Few toxicity cases have been related to selenium in food, although in Brazil nut producing areas, because of the high nut consumption rates, selenium intakes can sometimes be much higher than the DRI.


Protein fraction

In order to improve the calculation of protein contents in Brazil nut, we calculated the nitrogen/protein conversion factor by taking the amino-acid analysis results into account. The nitrogen content obtained by total carbonization of the defatted cake was 9.74%. The conversion factor thus obtained was 6.97 (Chunhieng et al., 2003 ). The defatted cake contained 97.47 mg/g of nitrogen, which means that there was a protein content of 67.9% in the defatted cake, and a whole nut protein content of 17.3%. This content is equivalent to that of Grenoble walnut (15.2%) (Dietobio, 2003) and almond (19%) (almondsarein.com, 2003). The amino-acid composition of Bertholletia excelsa proteins is similar to that of Cambodia nuts (Bandelier et al., 2002) (Table III). The lysine content is low (3.3%) and the sulfur amino acid content as methionine (6.3 %) and cystine (2.2 %) are high.

Lipid fraction

The oil content of fresh Brazil nut is 72.5%, which is much higher than that of almond (53%) and Grenoble walnut (55%). Brazil nut oil was solid at –18°C and then reliquified at –10°C, after 1.5 min of exposure at room temperature, showing a high level of unsaturation.

The fatty acid composition analysis confirmed this point, as 75.6% of the oil consists of monoand poly-unsaturated fatty acids (Table IV). This is lower than olive (83.3%), almond (87.0%) and walnut (83.0%) oils. The sum of unsaturated fatty acids C18:1 (39.3%) and C18:2 (36.1%) is close to 75%. The linoleic acid content (18:2%) is very high in comparison to almond or olive oils. Linolenic acid is absent. The high unsaturation of fatty acids and the high amount of linoleic acid give this oil some interesting dietary health properties.

Brazil nut oil is rich in β-tocopherol (88.3% of total tocopherols) (Chunhieng, 2003), whereas olive oil (Kamal-Eldin, Andersson, 1997) is characterized by a high α-tocopherol content (84.2%).

Brazil nut oil has a similar sterol composition as olive oil (Jiménez de Blas, Gonzalez, 1996). Its β-sitosterol content (76% of total sterols) is comparable to that of olive oil (81%) and almond oil (77%) (Itoh et al., 1974). A small quantity of cholesterol is present (2%) in Brazil nut oil, as in other comparable vegetable oils.


 
Claudia
Hugo
Juanp