Cashew trees (Anacardium occidentale) are native to areas around Northeastern Brazil. Portuguese colonists brought them around 1560 to Goa, India, from where they spread to Southeast Asia and finally Africa. Therefore, cashew products already have a long history in Goa and are very much considered a local food item. The main producers of cashew nuts nowadays are Cote d’Ivoire, India, and Vietnam. India was producing 18% of the world’s cashew nut production in 2020.
Cashew harvesting season is in Goa from about March to mid-May each year. The cashew fruit as a whole, consists of the cashew apple and the cashew nut. The cashew apple is a pseudo-fruit, a swollen hypocarp, and the cashew nut is the fruit (or drupe), which consists of shell and kernel. The shell outside the kernel consists of the hard shell and a growing part, called the testa.
Cashew apple
The cashew apple is a heavily swollen pedicel of the cashew nut (which in this case is a drupe with very thin fleshy skin). This ‘apple’ is very juicy, pleasantly fruity tasting with an astringent touch, and has stringy fibers inside. Cashew apples are mainly eaten fresh and eaten outdoors, as it is not easy to avoid dripping juices around. And – these apples getting bruised when falling from the tree and unbruised ones got a short shelf life.
In Goa, they are also used for cooking the local curry dish ‘Kaju Shaak’ and also for preparing a cashew apple cake. More popular and widespread are squeezing out the juices and either ferment them or not. This juice is either drunk fresh, or when fermented, vinegar can be produced, more popular, Goan Feni is distilled from them, with an alcohol content of finally 40% and above.
Cashew nuts
Green, mature cashew nuts
Green, mature cashew nuts are taken off the apple by a screwing action. They will be dried and thereafter either directly roasted on the ground or in a metal pot with a perforated bottom. The best fire fuel is dried palm leaves, as they are burning quite hot and can be spread out easily to areas, where nuts have to be roasted. The nuts are either directly spread onto dry ground, covered with palm leaves, and fire be lighted or put into the perforated pot.
When roasting, the nut shells will release anacardic acid, which causes allergic skin rash on contact. Nut shells should therefore be never roasted inside a closed room but always outside in the open air and the person handling the roasting should not get into the smoke.
Anacardic acid is a liquid resin, that will drip to the ground and when cooled down collected by people and used as a varnish or waterproofing agent e.g.: for boats. During roasting, anacardic acid will start burning on the nut shells and all the burning nuts will be spread out (or dipped from the pot) and the fires squashed. After cooling down, the nuts are cracked open, and the kernels can be eaten. For cracking the nuts, an anvil of inverted coconut shell halves or stones can be used and as a bludgeon either a wooden pestle or stone.
Sun-tanned cashew nuts
Sun-tanned cashew nuts, which were falling to the ground and were naturally roasted by the sun. These cashew nuts are taken on a brownish (‘sunburnt’) color outside. They can be opened without roasting and the kernels be eaten. I personally however would also roast these nuts, just to make sure, there is no anacardic acid left.
Green, baby cashew nuts
Green baby cashew nuts, where the pedicle is still not swollen up forming the apple. These can also be cracked open and eaten without roasting. But again, I would roast all types of cashew nuts, nevertheless if green baby, green mature or sun tanned.
Cashew kernel
Roasted cashew kernels are typically used as a snack food in Western cultures, and as ingredients for cooking in either whole or powdered form in Eastern cultures. Raw cashews contain about 5% water, 30% carbohydrates, 44% fat, and 18% protein and have a calorific value of 553 kcal/100g.
Cashew shell
In former times, cashew shells were buried in the ground, as they were regarded as toxic, due to their contents of phenolic lipids, anacardic acid, and cardanol, and were a source of environmental pollution. Nowadays, these shells are a new raw material, as the remaining oils in the shells are extracted, which are traded under the name of CNSL (Cashew Nut Shell Liquid). CNSL is a natural resin, which is found in the honeycomb structure of cashew nutshells. The main applications nowadays are as anti-termite paints of wood and for the production of carbon-composite products.
Cashew testa
The growth part of the nuts is also called ‘Cashew husk’ or ‘Cashew silk shell’ and is used as a supplement for animal feed. But also, as a dye and a source of tannin for the tanning industry.
Lessons learned about cashew apples and -nuts in Goa
- Cashew nuts are deeply ingrained in Goan culture
- Roasting of cashew nuts is an unhealthy affair, and care has to be taken not to inhale the smoke
- For shelling roasted nuts, gloves or other reliable skin protection should be worn
