Cashew apple refers to the swollen peduncle to which the nut is attached. Cashew apple, though very juicy and sweet, is not normally eaten because of its astringent and acrid principles. Cashew apple is between three and five inches long and has a smooth, shiny skin that turns from green to bright red, orange or yellow in colour as it matures. It has pleasant but strong astringent flavour. It is very rich in Vitamin C and contains four to five times as much Vitamin C as citrus. The cashew apple is also rich in sugars, and contains considerable amounts of tannins and minerals, mainly calcium, iron and phosphorous.
Until recently, the potential of cashew apple had not been investigated due to its highly astringent and acrid taste which is believed to originate in the waxy layer of the skin and which causes tongue and throat irritation after eating. Cashew fruit can be made suitable for consumption by removing the undesirable tannins and processing the apples into value-added products, such as juices, syrups, canned fruits, pickles, jams, chutneys, candy and toffee. The recommended methods for removing the astringent properties of the cashew apple include steaming the fruit for five minutes before washing it in cold water, boiling the fruit in salt water for five minutes, or adding gelatin solution to the expressed juice. The development of processing options for the cashew apple, has also been limited by its high degree of perishability, and consequent difficulties in transportation from growing areas to distant processing plants.
Cashew apple juice, being the highly nutritious food product that it is, merits closer attention because of its obvious health benefits and its economic potential for farmers, entrepreneurs and consumers. Furthermore, the fruit has medicinal properties. It is used for curing scurvy and diarrhoea, and it is effective in preventing cholera. It is applied for the cure of neurological pain and rheumatism.