The Cashew (Anacardium occidentale) is a tree in the flowering plant family Anacardiaceae. The plant is native to
northeastern Brazil, where it is called by its Portuguese name Caju (the fruit) or Cajueiro (the tree). It is now widely grown in
tropical climates for its cashew nuts and cashew apples.
Originally spread from Brazil by the Portuguese, the cashew tree today can be found in all regions with a sufficiently warm and
humid climate.
Anacardium occidentale, from Koehler's
Medicinal-Plants (1887)
What appears on the tree to be the fruit of the cashew tree is an oval to pear-shaped
accessory fruit or false fruit that develops from the receptacle of the cashew
flower. Called the cashew apple, better known in Panama as "marañón", it ripens
into a yellow and/or red structure about the size of a plum or pear
(5–11 cm).
The true fruit of the cashew tree is a roughly kidney-shaped or boxing-glove shaped drupe that
grows at the end of the pseudofruit. Actually, the drupe develops first on the tree, and then the peduncle expands into the
pseudofruit. Within the true fruit is a single seed, the cashew nut. Although a
nut in the culinary sense, in the botanical sense the fruit
of the cashew is a seed. However, the true fruit is classified as a nut by some botanists.
The seed is surrounded by a double shell containing a caustic phenolic resin. Some people are allergic to cashews, but cashews
are a less frequent allergen than some other nuts.
Uses
The cashew apple is used for its juicy but acidic pulp, which can be eaten raw or used in the production of jam, chutney, or various beverages. Depending on local customs, its juice is also
processed and distilled into liquor or consumed diluted and sugared as a refreshing
drink. In Goa, India, the cashew apple is the source of juicy pulp used to prepare
fenny, a locally popular distilled liquor. The cashew apple contains much tannin and is very perishable. For this reason, in many parts of the world, the false fruit is simply discarded
after removal of the cashew nut.
Cashew fruit contains a potent skin irritant toxin called urushiol (also found in poison-ivy) within the dark green nut shells. This
must be removed when the seed inside is processed for consumption; this is done by shelling the nuts, a somewhat hazardous
process, and exceedingly painful skin rashes (similar to poison-ivy rashes) among processing workers are common. In India
urushiol is traditionally used to control tamed elephants by its mahout (rider or keeper). The
so-called "raw cashews" available in health food shops have been cooked but not roasted or browned.
cashew nut snack, roasted and salted
Cashew nuts are a common ingredient in Asian cooking, for example, in dishes such as
"chicken with cashews". They can also be ground into a spread called cashew butter similar to
peanut butter. Cashews have a very high oil
content, and they are used in some other nut butters to add extra oil. In an off-the-shelf package of cashews found in the
United States, a 30-gram serving contained 180 calories (750 kilojoules), 70% of which was
fat.
The liquid contained within the shell casing of the cashew, known as Cashew Nutshell Liquid (CNSL), has a variety of
industrial uses which were first developed in the 1930s. CNSL is fractionated in a process similar
to the distillation of petroleum, and has two primary end products: solids that are pulverized
and used as friction particle for brake linings, and an amber-colored liquid that is aminated to
create phenalkamine curing agents and resin modifiers. Phenalkamines are primarily used in
epoxy coatings for the marine and flooring markets, as they have intense hydrophobic properties
and are capable of remaining chemically active at low temperatures.
References and external links
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