Cashew

Cashew is the common name of a tropical evergreen tree Anacardium occidentale, in the family Anacardiaceae. It is native to South America and is the source of the cashew nut and the cashew apple, an accessory fruit. The tree can grow as tall as Template:Convert, but the dwarf cultivars, growing up to Template:Convert, prove more profitable, with earlier maturity and greater yields. The cashew nut is edible and is eaten on its own as a snack, used in recipes, or processed into cashew cheese or cashew butter. The nut is often simply called a 'cashew'. The cashew apple is a light reddish to yellow fruit, whose pulp and juice can be processed into a sweet, astringent fruit drink or fermented and distilled into liquor.

In 2023, 3.9 million tons of cashew nuts were harvested globally, led by the Ivory Coast and India. In addition to the nut and fruit, the shell yields derivatives used in lubricants, waterproofing, and paints.<ref>Template:Cite book</ref>

Description

The cashew tree is large and evergreen, growing to Template:Convert tall, with a short, often irregularly shaped trunk.<ref name="eb">Template:Cite web</ref> The leaves are spirally arranged, leathery textured, elliptic to obovate, Template:Convert long and Template:Convert broad, with smooth margins. The flowers are produced in a panicle or corymb up to Template:Convert long; each flower is small, pale green at first, then turning reddish, with five slender, acute petals Template:Convert long. The largest cashew tree in the world covers an area around Template:Convert and is located in Natal, Brazil.Template:Cn

The fruit of the cashew tree is an accessory fruit (sometimes called a pseudocarp or false fruit).<ref name=morton>Template:Cite book</ref><ref name="cabi">Template:Cite web</ref> 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.<ref>Template:Cite journal</ref><ref name="duke">Template:Cite web</ref><ref name="eb" /> Called the cashew apple, better known in Central America as Template:Lang, it ripens into a yellow or red structure about Template:Convert long.<ref name="morton" /><ref name="duke" />

The true fruit of the cashew tree is a kidney-shaped or boxing glove-shaped drupe that grows at the end of the cashew apple.<ref name="morton" /> The drupe first develops on the tree and then the pedicel expands to become the cashew apple.<ref name="morton" /> The drupe becomes the true fruit, a single shell-encased seed, which is often considered a nut in the culinary sense.<ref name="morton" /><ref name="duke" /><ref>Template:Cite web</ref> The seed is surrounded by a double-shell that contains an allergenic phenolic resin,<ref name="duke" /> anacardic acid - which is a potent skin irritant<ref name="eb" /> chemically related to the better-known and also toxic allergenic oil urushiol, which is found in the related poison ivy and lacquer tree.

Etymology

The English name derives from the Portuguese name for the fruit of the cashew tree: Template:Wikt-lang (Template:IPA), also known as Template:Wikt-lang, which itself is from the Tupi word Template:Lang, literally meaning "nut that produces itself".<ref name=morton /><ref name=cabi/>

The generic name Anacardium is composed of the Greek prefix ana- (Template:Langx), the Greek cardia (Template:Langx), and the Neo-Latin suffix Template:Wikt-lang. It possibly refers to the heart shape of the fruit,<ref>Template:Cite book</ref> to "the top of the fruit stem"<ref>Merriam-Webster: "from the heartlike shape of the top of the fruit stem"</ref> or to the seed.<ref>Template:Cite book</ref> The word anacardium was earlier used to refer to Semecarpus anacardium (the marking nut tree) before Carl Linnaeus transferred it to the cashew; both plants are in the same family.<ref>Template:Cite book</ref> The epithet occidentale derives from the Western (or Occidental) world.<ref>Template:Cite web</ref>

The plant has diverse common names in various languages among its wide distribution range,<ref name=cabi/> including Template:Lang (French) with the fruit referred to as Template:Lang,<ref name="dyphon" /> Template:Wikt-lang (Template:IPA), or Template:Wikt-lang (Portuguese).<ref name=morton /><ref name=cabi/>

Distribution and habitat

The species is native to tropical South America<ref name=powo>Template:Cite web</ref> and later was distributed around the world in the 1500s by Portuguese explorers.<ref name=morton/><ref>Template:Cite web</ref><ref name=duke/> Portuguese colonists in Brazil began exporting cashew nuts as early as the 1550s.<ref>Carolyn Joystick, "Cashew Industry" in Encyclopedia of Latin American History and Culture, vol. 2, p. 5. New York: Charles Scribner's Sons 1996.</ref> The Portuguese took it to Goa, formerly Estado da Índia Portuguesa in India, between 1560 and 1565. From there, it spread throughout Southeast Asia and eventually Africa.Template:Cn

Cultivation

Cashew production (with shell) 2023
Country	Tonnes
Template:CIV	1,044,450
Template:IND	782,000
Template:VNM	347,634
Template:IDN	164,152
Template:PHL	136,264
World	3,934,839
Template:Small

The cashew tree is cultivated in the tropics between 25°N and 25°S, and is well-adapted to hot lowland areas with a pronounced dry season, where the mango and tamarind trees also thrive.<ref>Template:Cite web</ref> The traditional cashew tree is tall, up to Template:Cvt, requiring three years from planting before it starts production, and eight years before economic harvests.<ref name=PNACR262>Template:Cite web</ref><ref name=mekarsari>Template:Cite book</ref>

More recent breeds, such as the dwarf cashew trees, are up to Template:Cvt tall and start producing after the first year, with economic yields after three years. The cashew nut yields for the traditional tree are about Template:Cvt per hectare, in contrast to over a ton per hectare for the dwarf variety. Grafting and other modern tree management technologies improve and sustain cashew nut yields in commercial orchards.<ref name=PNACR262/><ref>Template:Cite web</ref>

Production

In 2023, global production of cashew nuts (as the kernel) was 3.9 million tonnes, led by Ivory Coast and India with a combined 46% of the world total (table).

Trade

Almost all cashews produced in Africa between 2000 and 2019 were exported as raw nuts which are much less profitable than shelled nuts.<ref>Template:Cite web</ref> One of the goals of the African Cashew Alliance is to promote Africa's cashew processing capabilities to improve the profitability of Africa's cashew industry.<ref>Template:Cite web</ref>

Toxicity

Some people are allergic to cashews, but they are a less frequent allergen than other tree nuts or peanuts.<ref name="Rosen">Template:Cite journal</ref> For up to 6% of children and 3% of adults, consuming cashews may cause allergic reactions, ranging from mild discomfort to life-threatening anaphylaxis.<ref name="Weinberger">Template:Cite journal</ref><ref name="allen">Template:Cite journal</ref><ref name="eu">Template:Cite web</ref><ref>Template:Cite web</ref> These allergies are triggered by the proteins found in tree nuts, and cooking often does not remove or change these proteins.<ref>Template:Cite web</ref> Reactions to cashew and 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.<ref name="allen" /><ref name="eu" />

The shell of the cashew nut contains oil compounds that can cause contact dermatitis similar to poison ivy, primarily resulting from the phenolic lipids, anacardic acid, and cardanol.<ref name="duke" /><ref>Template:Cite journal</ref> Because it can cause dermatitis, cashews are typically not sold in the shell to consumers.<ref>Template:Cite web</ref> Readily and inexpensively extracted from the waste shells, cardanol is under research for its potential applications in nanomaterials and biotechnology.<ref name="hamad">Template:Cite journal</ref>

Uses

Nutrition

Template:Nutritional value Raw cashew nuts are 5% water, 30% carbohydrates, 44% fat, and 18% protein (table). In a 100-gram reference amount, raw cashews provide 553 kilocalories, 67% of the Daily Value (DV) in total fats, 36% DV of protein, 13% DV of dietary fiber, and 11% DV of carbohydrates.<ref name="USDA">Template:Cite web</ref> Cashew nuts are rich sources (20% or more of the DV) of dietary minerals, including particularly copper, manganese, phosphorus, and magnesium (79-110% DV), and of thiamin, vitamin B₆, and vitamin K (32-37% DV).<ref name="USDA" /> Iron, potassium, zinc, and selenium are present in significant content (14-61% DV) (table).<ref name="USDA" /> Cashews (100g, raw) contain Template:Convert of beta-sitosterol.<ref name="USDA" />

Nut and shell

Culinary uses for cashew seeds in snacking and cooking are similar to those for all tree seeds called nuts.<ref name="morton" /><ref name="duke" />

Cashews are commonly used in Indian cuisine, whole for garnishing sweets or curries, or ground into a paste<ref name="duke"/> 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 of Goa Kaju are used whole for making curries and sweets. Cashews are also used in Thai and Chinese cuisines, generally in whole form. In the Philippines, cashew is a known product of Antipolo and is eaten with suman. The province of Pampanga also has a sweet dessert called turrones de casuy, which is cashew marzipan wrapped in white wafers. In Indonesia, roasted and salted cashews are called kacang mete or kacang mede, while the cashew apple is called jambu monyet (Template:Abbr 'monkey rose apple').Template:Cn

In the 21st century, cashew cultivation increased in several African countries to meet the manufacturing demands for cashew milk, a plant milk alternative to dairy milk.<ref>Template:Cite web</ref> In Mozambique, bolo polana is a cake prepared using powdered cashews and mashed potatoes as the main ingredients. This dessert is common in South Africa.<ref>Template:Cite book</ref>

Husk

The cashew nut kernel has a slight curvature and two cotyledons, each representing around 20-25% of the weight of the nut. It is encased in a reddish-brown membrane called a husk, which accounts for approximately 5% of the total nut. Cashew nut husk is used in emerging industrial applications, such as an adsorbent, composites, biopolymers, dyes, and enzyme synthesis.<ref>Template:Cite journal</ref>

Apple

The mature cashew apple can be eaten fresh, cooked in curries, or fermented into vinegar, citric acid,<ref>Template:Cite web</ref> or an alcoholic drink.<ref name="duke" /> It is also used to make preserves, chutneys, and jams in some countries, such as India and Brazil.<ref name="duke" /> In many countries, particularly in South America, the cashew apple is used to flavor drinks, both alcoholic and nonalcoholic.<ref name="morton" /><ref name="eb" />

In Brazil, cashew fruit juice and fruit pulp are used to make sweets, and juice mixed with alcoholic beverages such as cachaça, and as flour, milk, or cheese.<ref name="Edi Souza">Template:Cite web</ref> In Panama, the cashew fruit is cooked with water and sugar for a prolonged time to make a sweet, brown, paste-like dessert called Template:Lang (Template:Lang being a Spanish name for cashew).<ref>Template:Cite web</ref>

Cashew nuts are more widely traded than cashew apples, because the fruit, unlike the nut, is easily bruised and has a very limited shelf life.<ref name="Strom-2014">Template:Cite news</ref> Cashew apple juice, however, may be used for manufacturing blended juices.<ref name="Strom-2014" />

When the apple is consumed, its astringency is sometimes removed by steaming the fruit for five minutes before washing it in cold water. Steeping the fruit in boiling salt water for five minutes reduces the astringency.<ref>Template:Cite book</ref>

In Cambodia, where the plant is usually grown as an ornamental rather than an economic tree, the fruit is a delicacy and is eaten with salt.<ref name="dyphon" />

Alcohol

In the Indian state of Goa, the ripened cashew apples are mashed, and the juice, called "neero", is extracted and kept for fermentation<ref name="duke" /> for a few days. This fermented juice then undergoes a double distillation process. The resulting beverage is called feni or fenny. Feni is about 40-42% alcohol (80-84 proof). The single-distilled version is called urrak, which is about 15% alcohol (30 proof).<ref name="how-kaju-feni-is-made">Template:Cite web</ref> In Tanzania, the cashew apple (bibo in Swahili) is dried and reconstituted with water and fermented, then distilled to make a strong liquor called gongo.<ref>Template:Cite web</ref>

Nut oil

Cashew nut oil is a dark yellow oil derived from pressing the cashew nuts (typically from lower-value broken chunks created accidentally during processing) and used for cooking or salad dressing. The highest quality oil is produced from a single cold pressing.<ref>Template:Cite web</ref>

Shell oil

Cashew nutshell liquid (CNSL) or cashew shell oil (CAS registry number 8007-24-7) is a natural resin with a yellowish sheen found in the honeycomb structure of the cashew nutshell, and is a byproduct of processing cashew nuts. Since it is a strong irritant, it should not be confused with edible cashew nut oil. It is dangerous to handle in small-scale processing of the shells, but is itself a raw material with multiple uses.<ref name=hamad/> It is used in tropical folk medicine and for anti-termite treatment of timber.<ref name=clay /> Its composition varies depending on how it is processed.

• Cold, solvent-extracted CNSL is mostly composed of anacardic acids (70%),<ref name=cen/> cardol (18%), and cardanol (5%).<ref name=hamad/><ref name=epa>Template:Cite web</ref>
• Heating CNSL decarboxylates the anacardic acids, producing a technical grade of CNSL that is rich in cardanol. Distillation of this material gives distilled, technical CNSL containing 78% cardanol and 8% cardol (cardol has one more hydroxyl group than cardanol).<ref name=epa/> This process also reduces the degree of thermal polymerization of the unsaturated alkyl-phenols present in CNSL.
• Anacardic acid is also used in the chemical industry for the production of cardanol, which is used for resins, coatings, and frictional materials.<ref name=cen>Template:Cite journal</ref><ref name=epa />

These substances are skin allergens, like lacquer and the oils of poison ivy, and they present a danger during manual cashew processing.<ref name=clay>Template:Cite book</ref>

This natural oil phenol has interesting chemical structural features that can be modified to create a wide spectrum of biobased monomers. These capitalize on the chemically-versatile construct, which contains three functional groups: The aromatic ring, the hydroxyl group, and the double bonds in the flanking alkyl chain. These include polyols, which have recently seen increased demand for their biobased origin and key chemical attributes such as high reactivity, range of functionalities, reduction in blowing agents, and naturally occurring fire retardant properties in the field of rigid polyurethanes, aided by their inherent phenolic structure and larger number of reactive units per unit mass.<ref name=hamad/>

CNSL may be used as a resin for carbon composite products.<ref>Template:Cite web</ref> CNSL-based novolac is another versatile industrial monomer deriving from cardanol typically used as a reticulating agent (hardener) for epoxy matrices in composite applications<ref>Template:Cite journal</ref> providing good thermal and mechanical properties to the final composite material.<ref>Template:Cite journal</ref>

Animal feed

Discarded cashew nuts are unfit for human consumption and the residues of oil extraction from cashew kernels can be fed to livestock. Animals can also eat the leaves of cashew trees.<ref>Template:Cite web</ref>

Other uses

In addition to its nut and fruit, the plant has several other uses. In Cambodia, the bark gives a yellow dye, the timber is used in boat-making, and for house-boards, and the wood makes excellent charcoal.<ref name="dyphon">Template:Cite book</ref> The shells yield a black oil used as a preservative and water-proofing agent in varnishes, cement, and as a lubricant or timber seal.<ref name=duke/> Timber is used to manufacture furniture, boats, packing crates, and charcoal.<ref name=duke/> Its juice turns black on exposure to air, providing an indelible ink.<ref name=duke/>

See also

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

External links

• Template:Commons category inline