Nut of the Week - Cashew

Cashew Tree

The cashew is a tree in the family Anacardiaceae. Its English name derives from the Portuguese name for the fruit of the cashew tree, caju, which in turn derives from the indigenous Tupi name, acajú. Originally native to northern South America, it is now widely grown in tropical climates for its cashew seeds and cashew apples.

The tree is small 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 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 more well 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.

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

Cashew is very commonly used in Indian cuisine. The nut can be used whole for garnishing sweets or curries, or ground into a paste that forms a base of sauces for curries (eg.Korma), or some sweets. 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. The cashew apple is eaten raw or used in curries.

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 also appear in Thai cuisine and Chinese cuisine, generally in whole form.

In Malaysia, the young leaves are eaten raw in a salad or with Sambal belacan (shrimp paste with chili and lime).

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 period of time to make a sweet, brown, paste-like dessert called "dulce de marañón". Marañón is one of the Spanish names for cashew.

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).

Cashew nuts, salted