The cashew is native to northeastern Brazil. Its English name derives from the Portuguese name for the fruit of the cashew tree, “cajú”, which in turn derives from the indigenous Tupi name, “acajú”. What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit or false fruit that develops from the receptacle of the cashew flower and it ripens into a yellow and/or red structure. The smell is delicious and the juicy pulp is sweet.
The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the pseudofruit. 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.
The seed is surrounded by a double shell containing a dermatogenic 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. That’s why you must remove it before eating the fruit otherwise your mouth will be burn.
In Brazil, the cashew fruit juice is very popular all across the country. You can buy bottles of it at supermarkets. I love it.