Cashew nuts are popularly referred as Cashews throughout the world. Cashews are the seeds of the evergreen tropical tree, scientifically called Anacardiaceae occidentale that belongs to the Anacardiaceae family. The kidney-shaped seeds are found adhering to the base of the cashew fruit known as cashew apple. Cashew derives its name from the Portuguese word, "caju", which originally came from the aboriginal Tupi name acajú meaning "nut that produces itself". Cashews are one of the most popular cash crops. Cashew trees grown abundantly in the tropical regions of the world such as India and Brazil. Cashew apples are also treated as delicacy in Indian, Caribbean and Brazilian cuisines. The fruit is eaten when ripe and is very delicious but it is the cashew nut that is the prized possession of this fruit. The State of Kerala in India ranks first in the world in export of Cashews followed by Brazil and third by Africa. Vietnam is another major exporter of Cashews. While the Indian Cashews are comparatively smaller in size than the Brazilian cashews they are more crisp in texture.
Cashews are native to the Northeastern Brazil. In 1578, Cashews were discovered by the Brazilians. In the 16th century, Portuguese explorers introduced Cashews to East Africa and they spread from Africa to the west coast of India. In India, Cashew plants were planted along the coastal belt to stop erosion. Later, people started using both the nuts (seeds) and the pseudo-fruit(cashew apples). Kerala is the state that tops the production of Cashews.
A cashew tree is similar in height to an apple tree roughly growing to 30 ft in height. When the branches reach the ground they can take root and grow into new trees. The cashew tree has Cashew apples which are the swollen stem of the cashew nut. These cashew apples are high in Vitamin C apples and vary in color from a red to yellow attracting a lot of birds. The tree grows in sandy soil and does not need a lot of care. When the cashew apple is ripe and the nut turns grey in color it is ready for picking. Cashew nuts need not be shelled right away as they can be stored in their shells at least for a couple of years. Shelling cashew nuts is not an easy task like other nuts. The nuts have a cover which is filled with a toxic fluid, cardol which can burn holes in the skin or cause blisters. Therefore the nuts have to processed before eating them. Though initially they were opened manually or heated which was again not a very safe process because the nuts exploded while heating spewing out the toxic cardol which resulted in blisters. Today the nuts are processed much more safely on the commercial front.Corrosive shells are removed carefully to extract the kernel. Workers use gloves during this entire process. Later kernels are soaked overnight in turmeric water to remove the harmful compounds before roasting. Cashew nut roasting is mostly done outdoors as the smoke contains anacardic acid droplets which can affect the lungs and cause a life threatening situation. Proper shelling and roasting eliminates toxic substances from the nuts and makes it safe for consumption.
Medicinal and Commercial Uses:
Raw Cashews are double-shelled. Studies have shown that these shells contain toxic compounds such as phenolic resin and anacardic acid. The phenolic resin is also called cashew balm and commercially used to produce varnish and insecticide. The anacardic acid is a potential skin irritant and closely resembles urushiol oil found in the leaves of poison ivy. Cashew allergy symptoms occur when the human body trigger histamine and Ig E (immunoglobulin E) antibody. Mild allergy symptoms are mild rash, upset stomach, nausea,vomiting, diarrhea, dehydration, hives, eczema, itchy eyes, mouth and throat swelling. Severe allergy symptoms are difficulty in breathing, wheezing, asthma attack, and facial edema. In fatal allergic reaction, low blood pressure may result in anaphylaxis. Children and pregnant women are more susceptible to developing Cashew allergies.