Macadamia (Macadamia nut genus)

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Eudicotyledons > Order: Proteales > Family: Proteaceae

Ten species, native to subtropical eastern Australia, Indonesia and New Caledonia. Macadamia nuts come from Macadamia integrifolia (Smooth macadamia nut) and Macadamia tetraphylla (Rough macadamia nut). Besides the two nut-producing species, Macadamia ternifolia is also cultivated in southern Africa.

The 10 species of Macadamia are native to subtropical eastern Australia, Indonesia and New Caledonia. Two Australian species, the Smooth Macadamia Nut Macadamia integrifolia and the Rough Macadamia Nut Macadamia tetraphylla have been cultivated for their nuts since about 1860. In the 1880's cultivation spread from Australia to Hawaii and in both places, new cultivars were produced, often involving hybridisation of the two species which are interfertile. Macadamia nuts are now grown in other parts of the world including Central America and South Africa. Prior to their cultivation, wild macadamia nuts were harvested by Australia Aborigines by picking up fallen nuts. This method of collection is evidently still used in cultivated orchards but it is time consuming and methods of mechanical harvesting are being investigated.

Macadamia trees have similar soil and climatic requirements to Avocado trees and have been grown successfully in areas where Avocados have been killed by soil fungus disease.

The fat content of Macadamia nuts is high, amounting to about 72%, primarily made up of monounsaturated fats. They are an excellent source of copper, magnesium and thiamin and a good source of iron and niacin.

Besides the two nut-producing species, Macadamia ternifolia is also cultivated in southern Africa.

Uses

• They are a popular snack, eaten be eaten raw or roasted.
• Chopped macadamias add texture and flavour to curries, salads, rice dishes, baked goods, sweets and ice cream.
• Nuts can be ground into a creamy butter used as a spread.
• Oil from pressed nuts is added to salads or used in cooking.

References

• Anon. 2002. Encyclopedia of Foods. A Guide to Healthy Nutrition. Academic Press, San Diego, California. 

• Sauer, J.D. 1993. Historical geography of crop plants - a select roster. CRC Press, Boca Raton, Florida.

Text by Hamish G. Robertson