The cashew apple, produced from the cashew tree (Anacardium occidentale), is not really a fruit. The true fruit of the tree is the cashew nut, while the cashew apple is the fleshy stalk that connects the cashew nut to the tree. The cashew tree is native to Brazil and grows both wild and cultivated. From there the plant spread throughout South America and was transported by European explorers to India, East Africa, and Florida. Most countries only harvest the cashew nuts, leaving the cashew apples behind for birds and monkeys. The apples are sometimes used as livestock food. However, some countries such as Brazil commonly consume the cashew apples as well as the nuts.
The cashew plant is an evergreen tall tree that grows wild in warm region forests. The tree has many oblong shiny leaves that are dark green. The branches of the tree produce clusters of yellow-pink flowers during March and April. These flowers initially develop into individual cashew nuts surrounded by a hard shell. The nuts are attached to the branches of the tree by a thin stalk. Once the nut has fully matured the stalk gets thicker and develops a thin skin that surrounds a fibrous flesh. This part is considered the cashew apple. The skin is yellow to red in color and the flesh is juicy with a unique acidic and sweet flavor. The pulp is rather astringent due to the high level of tannins, especially in the red-skinned apples. The apple and nut fall together as a unit from the tree when they are ripe. This unit looks somewhat like a tiny pear, where the apple looks like the fruit and the cashew nut looks like the stem.
Because they are so perishable, cashew apples are near impossible to find outside of their growing region. Fresh apples should be eaten immediately or stored in the fridge for no more than a few days. The fruit and skin of the apple is not poisonous and can be eaten fresh, but the shell surrounding the cashew nut contains toxic oils and should be avoided. Cashew nuts have to be roasted and shelled before eating to remove these oils. The most common way to eat a fresh cashew apple is to chew on the flesh in order to get the juice. The pulp is very fibrous and generally discarded. Fresh apple flesh is frequently crushed to obtain syrup and juice for various drinks. Fermented apples are also used to make a special liquor in India called feni. Cashew apples are often canned and preserved in sweet syrup. They may be candied or made into jams and preserves.
http://www.hort.purdue.edu/newcrop/morton/cashew_apple.html
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