Cashew, Caju

Anacardium occidentale

Physical Characteristics

Anacardium occidentale is an evergreen Tree growing to 12 m (39ft) by 20 m (65ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 10 and is frost tender. The flowers are pollinated by Flies, Bees, Ants, Wind. The plant is self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil and can tolerate drought. The plant can tolerates strong winds but not maritime exposure.

Distribution

S. America - Brazil.

Habitats

Edible Uses

Edible Parts: Fruit Leaves Oil Seed Shoots Edible Uses: Gum Oil Edible portion: Nut, Leaves, Fruit pulp, Flavouring, Vegetable, Seeds, Oil. Fruit - raw or cooked. Juicy and refreshing, though they are a bit acidic and often have an astringency that can leave your mouth feeling furry[ 63 , 296 ]. They are also somewhat fibrous[ 63 ]. They can also be dried or sliced with other fruits[ 296 ]. The fruit can also be lightly cooked to get rid of their astringency[ 296 ]. A refreshing juice can be extracted from the fruit[ 63 ]. Red fruits are considered to be superior to yellow fruits[ 307 ]. The apple is used to make spirits. The fruit is about 3cm long[ 307 ]. Seed - must be cooked before being removed from its shell[ 63 ]. Slightly sweet with a pleasant, bland flavour[ 63 ]. Eaten on their own, salted and used in a wide range of confections[ 63 ]. They can also be used as the basis of savoury protein-rich meat-alternative dishes[ K ]. Caution should be employed when harvesting the seed - see notes above on toxicity. An edible oil is obtained from the seed but, due to the high value of the seed, the oil is not usually extracted[ 324 ]. Young leaves and shoots - raw in salads or cooked[ 298 , 320 , 404 ]. Eaten in S.E. Asia, but too astringent for most tastes[ 298 ]. They are picked during the rainy season and eaten fresh with hot and spicy dishes. One of our users, Carol, from the tropics of northern Australia, kindly forwarded the following information. Safely processing cashew nuts at home. 1. It is best to fill a lidded oven-safe pot with sand and bury the unopened nuts completely in the sand. Use an old pot as after processing the pot will not be suitable to use for any other purpose due to traces of the caustic latex that may remain behind. I have a lidded casserole dish dedicated solely for this purpose. 2. Preheat the oven to around 250 deg C and roast the nuts in their shell for 10 minutes. Make sure to have windows open and the kitchen well ventilated as the heat causes the shell to crack and the caustic latex to ooze out. While the sand will absorb the oil, it may also emit a caustic choking smoke, avoid inhaling this! Take extreme care opening the oven door. I would recommend taking the lidded pot outdoors before removing the lid. Better still, if you have an outdoor stove, use that from the start. 3. Wear disposable gloves when you open the pot and carefully remove the nuts from the sand as they may have some oil residue. Place the whole roasted nuts in a dish of water and detergent and thoroughly wash them. 4. It should now be safe to open the shell and remove the kernel. Finally, remove the thin brown papery cover from the kernel. 5. Note that if any of the latex has stuck to the roasted kernel during processing then that nut(kernel) is not edible and must be thrown out. 6. If like me you are a hobby gardener or a subsistence farmer, and not growing commercial quantities, the unopened nuts can be stored for a couple of years until enough nuts have been stored to warrant processing. My tree produced one cashew apple and nut in its first year and I certainly was not going to go through that process for one solitary nut!

Medicinal Uses

Antidiarrhoeal Antifungal Antiscorbutic Astringent Astringent Cholera Contraceptive Diuretic Febrifuge Foot care Hypoglycaemic Leprosy Malaria Purgative Rubefacient Skin Vesicant Vesicant The leaves are febrifuge[ 238 ]. They are used in west Africa in the treatment of malaria[ 254 ]. In India and Africa the leaves are used to treat toothache and gum problems[ 254 ]. The leaves can be harvested at any time and dried for later use[ 238 ]. The bark is astringent, rubefacient and vesicant[ 303 ]. Research has shown that it is also hypoglycaemic, having the ability to reduce blood sugar levels[ 238 ]. The bark is used in Ayurvedic medicine to detoxify snake bites[ 254 ]. The bark is harvested as required and used fresh or dried[ 238 ]. Leaf and bark infusions are used in the treatment of toothache and sore gums, whilst the bark and leaf extracts and fruit juice are taken internally to treat diarrhoea[ 238 ]. The fruit is anti-scorbutic, astringent and diuretic[ 238 , 303 ]. Cashew syrup is a good remedy for coughs and colds. Cashew apple juice is said to be effective for the treatment of syphilis, and is also used in the treatment of cholera and kidney troubles[ 303 ]. The fresh, acrid juice inside the shell is vesicant[ 324 ]. It has been used for removing warts[ 63 , 238 ] as well as for treating ringworm, leprosy and corns[ 238 ], and is applied to the soles of the feet to cure cracks in the skin[ 303 ]. It is toxic to many disease-causing organisms, such as Staphylococcus bacteria[ 238 ]. The sap, or bark extract[ 238 ], is considered to be contraceptive[ 307 ]. The gum is bactericidal, fungicidal and kills worms and protozoa[ 254 ]. It is applied externally in the treatment of leprosy, and for corns and fungal conditions[ 254 ]. An infusion of the root is an excellent purgative[ 303 ].

Known Hazards

The shell of the nut contains an acrid juice that acts as a powerful vesicant[ 63 ]. The active ingredient is cardole and it is poisonous in the same way as poison ivy (Toxicodendron spp.)[ 63 , 200 ]. Very irritant to the skin, causing severe blistering[ 63 ]. It is destroyed by heat, so roasting the seed whilst in its shell renders it completely safe[ 63 , 200 ].(Handling plant may cause skin irritation or allergic reaction )