Cashew

Cashew
Cashews ready for harvest in Kollam, India
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Sapindales
Family:	Anacardiaceae
Genus:	Anacardium
Species:	A. occidentale
Binomial name
Anacardium occidentale L.

The cashew, Anacardium occidentale, is a tree in the family Anacardiaceae. Its English name derives from the Portuguese name for the fruit of the cashew tree, caju (Portuguese pronunciation: [kɐˈʒu]), which itself is derived from the indigenous Tupi name, acajú. Originally native to Northeastern Brazil, it is now widely grown in tropical climates for its cashew apples and nuts.

Etymology

The name Anacardium actually refers to the shape of the fruit, which looks like an inverted heart (ana means "upwards" and -cardium means "heart"). In the Tupian languages acajú means "nut that produces itself".

Habitat and growth

'Anacardium occidentale', from Koehler's 'Medicinal-Plants' (1887)

Cashew tree

Cashew growing regions in 2006. The yield per hectare data is off-scale per FAOSTAT database.

The tree is large and evergreen, growing to 10-12m (~32 ft) tall, with a short, often irregularly shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, 4 to 22 cm long and 2 to 15 cm broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 cm long, each flower small, pale green at first then turning reddish, with five slender, acute petals 7 to 15 mm long. The largest cashew tree in the world covers an area of about 7,500 square metres (81,000 sq ft).

The fruit of the cashew tree is an accessory fruit (sometimes called a pseudocarp or false fruit). What appears to be the fruit is an oval or pear-shaped structure, a hypocarpium, that develops from the pedicel and the receptacle of the cashew flower. Called the cashew apple, better known in Central America as "marañón", it ripens into a yellow and/or red structure about 5–11 cm long. It is edible, and has a strong "sweet" smell and a sweet taste. The pulp of the cashew apple is very juicy, but the skin is fragile, making it unsuitable for transport. In Latin America, a fruit drink is made from the cashew apple pulp which has a very refreshing taste and tropical flavor that can be described as having notes of mango, raw green pepper, and just a little hint of grapefruit-like citrus.

The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the cashew apple. The drupe develops first on the tree, and then the pedicel expands to become the cashew apple. Within the true fruit is a single seed, the cashew nut. Although a nut in the culinary sense, in the botanical sense the nut of the cashew is a seed. The seed is surrounded by a double shell containing an allergenic phenolic resin, anacardic acid, a potent skin irritant chemically related to the better-known allergenic oil urushiol which is also a toxin found in the related poison ivy. Properly roasting cashews destroys the toxin, but it must be done outdoors as the smoke (not unlike that from burning poison ivy) contains urushiol droplets which can cause severe, sometimes life-threatening, reactions by irritating the lungs. People who are allergic to cashew urushiols may also react to mango or pistachio which are also in the Anacardiaceae family. Some people are allergic to cashew nuts, but cashews are a less frequent allergen than nuts or peanuts.

Dispersal

While native to Northeast Brazil, the Portuguese took the cashew plant to Goa, India, between the years of 1560 and 1565. From there it spread throughout Southeast Asia and eventually Africa.

Production

Top Ten Cashew Nuts (with shell) Producers in 2010
Country	Production (metric tons)	Yield (MT/hectares)
Nigeria	650,000	1.97
India	613,000	0.66
Côte d'Ivoire	380,000	0.44
Vietnam	289,842	0.85
Indonesia	145,082	0.25
Philippines	134,681	4.79
Brazil	104,342	0.14
Guinea-Bissau	91,100	0.38
Tanzania	80,000	1.0
Benin	69,700	0.29
World Total	2,757,598	0.58
Source: Food & Agriculture Organization

Nigeria was the world's largest producer of cashew nuts with shell in 2010. Cashew nut production trends have varied over the decades. African countries used to be the major producers before 1980s, India became the largest producer in 1990s, followed by Vietnam which became the largest producer in mid 2000s. Since 2008, Nigeria has become the largest producer. Cashew nuts are produced in tropical countries because the tree is very frost sensitive; they have been adapted to various climatic regions around the world between the latitudes of 25-deg. north and south.

Peru reported the world's highest production yields for cashew nuts in 2010, at 5.27 metric tons per hectare, nearly nine times the world average yield per hectare. The traditional cashew tree is tall (up to 14 meters) and takes 3 years from planting before it starts production, and 8 years before economic harvests can begin. More recent breeds such as the dwarf cashew tree are up to 6 meters tall, start producing after the 1st year, with economic yields after 3 years. The cashew nut yields for the traditional tree are about 0.25 metric tons per hectare, in contrast to over 1 ton per hectare for the dwarf variety. Grafting and other modern tree management technologies are used to further improve and sustain cashew nut yields in commercial orchards.

Fluctuations in world market prices for cashew nuts have been a source of discontent for communities in Tanzania which grow the nut as a cash crop; reduced payments in April 2013 sparked serious rioting in Liwale District in the south of the country.

Uses

Medicine and industry

Cashew nuts, salted

Main article: Cashew nutshell liquid

The cashew nutshell liquid (CNSL), a byproduct of processing cashew, is mostly composed of anacardic acids (70%), cardol (18%) and cardanol (5%). These acids have been used effectively against tooth abscesses due to their lethality to a wide range of Gram-positive bacteria. Many parts of the plant are used by the Patamona of Guyana medicinally. The bark is scraped and soaked overnight or boiled as an antidiarrheal; it also yields a gum used in varnish. Seeds are ground into powders used for antivenom for snake bites. The nut oil is used topically as an antifungal and for healing cracked heels.

Anacardic acid is also used in the chemical industry for the production of cardanol, which is used for resins, coatings, and frictional materials.

Culinary

Cashew nuts, roasted and salted

The cashew nut is a popular snack, and its rich flavor means that it is often eaten roasted, on its own, lightly salted or sugared, or covered in chocolate.

Cashews, unlike other oily tree nuts, contain starch to about 10% of their weight. This makes them more effective than other nuts in thickening water-based dishes such as soups, meat stews, and some Indian milk-based desserts. Many southeast Asia and south Asian cuisines use cashews for this unusual characteristic, rather than other nuts.

The shell of the cashew nut is toxic, which is why the cashew is shelled before it is sold to consumers.

Cashew is commonly used in Indian cuisine. The nut is used whole for garnishing sweets or curries, or ground into a paste that forms a base of sauces for curries (e.g., Korma), or some sweets (e.g., Kaju Barfi). It is also used in powdered form in the preparation of several Indian sweets and desserts. In Goan cuisine, both roasted and raw kernels are used whole for making curries and sweets.

Cashew sprouts (above) are eaten raw as well as cooked in Kerala. Cashew nuts germinate within days after falling; these are generally collected from the ground after harvesters finish; or if the rains arrive before harvesting is complete.

The cashew nut can also be harvested in its tender form, when the shell has not hardened and is green in color. The shell is soft and can be cut with a knife and the kernel extracted, but it is still corrosive at this stage, so gloves are required. The kernel can be soaked in turmeric water to get rid of the corrosive material before use. This is mostly found in Kerala cuisine, typically in avial, a dish that contains several vegetables, grated coconut, turmeric and green chilies.

Cashew nuts are also used in Thai and Chinese cuisine, generally in whole form.

In the Philippines, cashew is a known product of Antipolo, and is eaten with suman. Pampanga also has a sweet dessert called turrones de casuy which is cashew marzipan wrapped in white wafer.

In Indonesia, roasted and salted cashew nut is called kacang mete or kacang mede, while the cashew apple is called jambu monyet (literally means monkey rose apple).

In Mozambique, bolo polana is a cake prepared using powdered cashews and mashed potatoes as the main ingredients. This dessert is popular in South Africa too.

South American countries have developed their own specialties. In Brazil, the cashew fruit juice is popular all across the country. In Panama, the cashew fruit is cooked with water and sugar for a prolonged time to make a sweet, brown, paste-like dessert called "dulce de marañón". Marañón is one of the Spanish names for cashew.

Cashew apple

Cashew apple with nut

Cashew apples for sale near Sangareddy, Andhra Pradesh, India.

The cashew apple, also called cashew fruit, is the fleshy part of the cashew fruit that is attached to the cashew nut. The top end of the cashew apple is attached to the stem that comes off of the tree. The bottom end of the cashew apple attaches to the cashew nut, which is encased in a shell. In botanical terms, the cashew apple is an accessory fruit that grows on the cashew seed (which is the nut).

The cashew apple is a soft fruit, rich in nutrients and contains five times more vitamin C than an orange. It is eaten fresh, cooked in curries, or fermented into vinegar as well as an alcoholic drink. It is also used to make preserves, chutneys and jams in some countries such as India and Brazil. In many countries, particularly in South America, the cashew apple is used to flavor drinks, both alcoholic and non-alcoholic. In Brazil, it is a popular fruit flavor for the national drink, the caipirinha.

In much of South America, people regard the cashew apple as the delicacy, rather than the nut kernel which is popular elsewhere. In fact, in many South American countries, the cashew apple is more popular as a food than is the cashew nut. A large reason for this is simply the availability of cashew apples. They tend to be popular where they are readily available.

Cashew nuts are more popular than cashew apples in many parts of the world—regions that do not grow cashews—because the fruit, unlike the nut, is difficult to transport to these places. Unlike cashew nuts, cashew apples are extremely soft and easily bruised in shipment. For this reason, cashew juice and cashew juice concentrate are often shipped to these non-local countries instead of the fresh fruit.

Cashew apples have a sweet but astringent taste. This astringency has been traced to the waxy layer on the skin that contains a chemical, urushiol, which can cause minor skin irritation to areas that have had contact with it. It is almost identical to the astringency caused by the skin of a mango, which also contains urushiol. The astringency from mango skin can be mildly tasted in the flesh of mango fruit, just as the astringency of cashew apple skin can be mildly tasted in the flesh of cashew apples. In cultures that consume cashew apples, this astringency is sometimes removed by steaming the fruit for five minutes before washing it in cold water; alternatively boiling the fruit in salt water for five minutes or soaking it in gelatin solution also reduces the astringency. When mixed in drinks or used as a flavoring, the astringincy becomes highly diluted and typically causes no irritation to those without urushiol allergies.

Alcohol

young cashew nuts

In Goa, India, the cashew apple (the accessory fruit) is mashed, the juice is extracted and kept for fermentation for 2–3 days. Fermented juice then undergoes a double distillation process. The resulting beverage is called feni. Fenny/feni is about 40-42% alcohol. The single distilled version is called "Urrac" (the 'u' is pronounced ~ 'oo') which is about 15% alcohol.

In the southern region of Mtwara, Tanzania, the cashew apple (bibo in Swahili) is dried and saved. Later it is reconstituted with water and fermented, then distilled to make a strong liquor often referred to by the generic name, gongo.

In Mozambique, it is very common among the cashew farmers to make a strong liquor from the cashew apple which is called "agua ardente" (burning water).

According to An Account of the Island of Ceylon written by Robert Percival an alcohol had been distilled in the early twentieth century from the juice of the fruit, and had been manufactured in the West Indies. Apparently the Dutch considered it superior to brandy as a "liqueur."

Nutrition

cashew nuts, raw

Nutritional value per 100 g (3.5 oz)
Energy	2,314 kJ (553 kcal)
Carbohydrates	30.19 g
- Starch	23.49 g
- Sugars	5.91 g
- Dietary fiber	3.3 g
Fat	43.85 g
- saturated	7.78 g
- monounsaturated	23.8 g
- polyunsaturated	7.85 g
Protein	18.22 g
Water	5.2 g
Thiamine (vit. B1)	.42 mg (37%)
Riboflavin (vit. B2)	.06 mg (5%)
Niacin (vit. B3)	1.06 mg (7%)
Pantothenic acid (B5)	.86 mg (17%)
Vitamin B6	.42 mg (32%)
Folate (vit. B9)	25 μg (6%)
Vitamin C	.5 mg (1%)
Vitamin E	.9 mg (6%)
Calcium	37 mg (4%)
Iron	6.68 mg (51%)
Magnesium	292 mg (82%)
Manganese	1.66 mg (79%)
Phosphorus	593 mg (85%)
Potassium	660 mg (14%)
Sodium	12 mg (1%)
Zinc	5.78 mg (61%)
Percentages are relative to US recommendations for adults. Source: USDA Nutrient Database

The fats and oils in cashew nuts are 54% monounsaturated fat (18:1), 18% polyunsaturated fat (18:2), and 16% saturated fat (9% palmitic acid (16:0) and 7% stearic acid (18:0)).

Cashews, as with other tree nuts, are a good source of antioxidants. Alkyl phenols, in particular, are abundant in cashews. Cashews are also a good source of dietary trace minerals copper, iron and zinc.

Allergy

For some people, cashews, like other tree nuts, can lead to complications or allergic reactions. Cashews contain gastric and intestinal soluble oxalates, albeit less than some other tree nuts; people with a tendency to form kidney stone may need moderation and medical guidance. Allergies to tree nuts such as cashews can be of severe nature to some people. These allergic reactions can be life-threatening or even fatal; prompt medical attention is necessary if tree nut allergy reaction is observed. These allergies are triggered by the proteins found in tree nuts, and cooking often does not remove or change these proteins. Reactions to cashew and other tree nuts can also occur as a consequence of hidden nut ingredients or traces of nuts that may inadvertently be introduced during food processing, handling or manufacturing. Many nations require food label warning if the food may get inadvertent exposure to tree nuts such as cashews.

In some people, cashew nut allergy may be a different form, namely birch pollen allergy. This is usually a minor form. Symptoms are confined largely to the mouth.

An estimated 1.8 million Americans (between 0.4%-0.6% of the population) have an allergy to tree nuts. Young children are most affected; and tree nuts allergies tend to last lifelong. Some regions of the world have higher incidence rates than others.

Bark of Cashew tree

See also

• Cajuina
• List of culinary nuts
• Semecarpus anacardium (the Oriental Anacardium) is a native of India and is closely related to the cashew.

External links

• Handbook of Energy Crops - Anacardium occidentale L.

Further reading

• Klaus von Freyhold: The cashew sector in Ghana, in: Hans-Heinrich Bass (Hrsg.): Promoting the Production of Cashew, Shea, and Indigenous Fruits in West Africa, ITD Annual Report Supplement 2, 2013, p. 13-18, http://nbn-resolving.de/urn:nbn:de:0168-ssoar-338461
• Morton, Julia F. Fruits of Warm Temperatures. ISBN 978-0-9610184-1-2 [2]. Cashew Apple. p. 239–240.[3]
• Pillai, Rajmohan and Santha, P. The World Cashew Industry (Rajan Pillai Foundation, Kollam, 2008).nm.
• Morton, J. F. (2003). "Cashew nuts and cashew apples". Encyclopedia of Food Sciences and Nutrition. pp. 958–964. doi:10.1016/B0-12-227055-X/00180-2. ISBN 9780122270550.