Macadamia nut products, nutrition, and more
Macadamia nuts are one of the most delicious nuts in the World. They are crispy with a buttery flavor and can be used for the preparation of a number of enjoyable foods, like cakes and cookies. Raw, roasted, fried, salted, caramelized, or chocolate-covered, they are popular in the market all around the World.
The macadamia nut tree originates from Australia and was introduced to mostly tropical climates all around the world, where it’s now cultivated. Most delicious nuts presumably come from Hawaii, where the tree was introduced already in 1880 and where its commercial potential for the dessert nut was developed in the University of Hawaii (1). Today, the largest producers include Australia, Hawaii, Brazil, Indonesia, Peru, Fiji, Kenya, Israel, Colombia, Venezuela, New Zealand, Eastern, and Southern Africa.
Nutrition and bioactive compounds
Macadamia nuts are not only tasty but also nutritious. They are a high-energy food, with a high content of monounsaturated fatty acids (MUFA) which significantly reduce cholesterol (2). The highest quality kernels contain 72–78% of oil and 1.5% of moisture. The content depends on the Macadamia nut’s variety, cultivation, method of extraction, and geographical region. For example, oil content in macadamia kernels from China and New Zealand ranged from 69 to 78% in Shuai et al. study, whereas it was much lower in Brazil (33.1–68.5%) (3).
Unsaturated fatty acids in Macadamia nut account for more than 80% of the total fatty acid content and include oleic, palmitic, palmitoleic, linoleic, linolenic, eicosenoic, and docosanol acid (2–4). Macadamia nuts are one of the rare food sources that contain palmitoleic acid, a beneficiary fatty acid with anti-inflammatory and lipid-lowering activity, leading to prevention of metabolic syndrome, including cardiovascular disease and insulin resistance associated with diabetes and obesity.
The content of proteins is around 8% and dietary fibers around 8–9%. Macadamia peptide components are rich in amino acids, containing most of the essential ones (all except tryptophan). In the recent amino acids’ analysis (5), essential amino acids ranged from 190 to 281 mg/g and hydrophobic amino acids from 204 to 259 mg/g. Minerals found in the kernels were magnesium (114–246 mg/100g of nuts), calcium (78–109 mg/100g), zinc (1.1–1.4 mg/100g), iron (3.1–5.2 mg/100g), potassium (353–382 mg/100g), phosphorus (170–203 mg/100g) and sodium (3–6 mg/100g) (6).
Macadamia nuts also pose anti-oxidative capacity, which was mostly contributed to the polyphenols and squalene (3).
In addition to eating the nuts themselves, kernels can be processed to make the macadamia butter for cooking. The oil is also used in cuisine but has an important value in cosmetics as well. It can be found in creams and other skin products, sunscreens, shampoos and hair products, soaps, etc.
Although kernels are the main products of Macadamia nut, other parts have value as well. Shells can be used as mulch, fuel for processing the macadamia nuts and planting medium, while husks are used for the fuel or fertilizer (after composting) (1). The remaining press cake from oil production has a great potential to be included in the animal feed (7).
Macadamia nut’s market is on the rise. It is predicted to grow due to the rising demand for the food and food supplements with health benefits. New products are entering the market, underpinning further industry growth and cultivation, including in Africa (1). The market for Macadamia nuts is already global, with the highest market share in Asia-Pacific, North America and Western Europe (8).
The Macadamia nut tree was discovered by the German Australian physician and botanist Ferdinand von Mueller in the 1850s and decided to name the genus after his colleague John Macadam (1).
1. Verma MK, Yadav A, Nayan Deepak G, Usha K, Kumar S (2017): MACADAMIA NUT (Macadamia integrifolia), Chapter 28. In: Minor Fruits: Nutraceutical Importance and Cultivation, NS Ghosh (Ed.), Edition: Part-II, Jaya Publishing House, Delhi-110095 (India), pp. 583–605; https://www.researchgate.net/publication/321904724_MACADAMIA_NUT_Macadamia_integrifolia
2. Sáez A, Montoya S, Cabrera J, Asensio C, Ortega E (2014): Characterization and lipid profile of macadamia nuts (Macadamia integrifolia and Macadamia tetraphyllia). International Journal of Engineering and Applied Sciences 4(9):33–39. https://www.researchgate.net/publication/276264034
3. Shuai X, Dai T, Chen M, Liang R, Du L, Chen J, Liu C (2021): Comparative Study of Chemical Compositions and Antioxidant Capacities of Oils Obtained from 15 Macadamia (Macadamia integrifolia) Cultivars in China. Foods 10:1031. https://doi.org/10.3390/foods10051031
4. Ribeiro APL, Haddad FF, de Sousa Tavares T, Magalhaes KT, Pimenta CJ, Nunes CA (2020): Characterization of macadamia oil (Macadamia integrifolia) obtained under different extraction conditions. Emirates Journal of Food and Agriculture 32(4):295–302; doi: 10.9755/ejfa.2020.v32.i4.2095
5. Shuai X, Li Y, Zhang M, Ma F, Du L (2021): Amino Acid Composition and Functional Properties of Different Molecular Weight Segments of Macadamia Peptides. IOP Conf. Series: Earth and Environmental Science 769, IOP Publishing; doi: 10.1088/1755–1315/769/2/022030
6. U.S. Department of Agriculture, Agricultural Research Service: https://fdc.nal.usda.gov/fdc-app.html#/food-details/170178/nutrients
7. Marconato MNS, Sanches TP, Chaves CMS, Bueno MS, Issakowicz J, Haguiwara MMH, de Paz CCP, dos Reis LL, Abdalla AL, da Csta RLD (2021): Growth performance, carcass traits and meat quality of lambs fed increasing level of Macadamia nut cake. An Acad Bras Cienc 93(2): e20190852; doi: 10.1590/0001–3765202120190852
8. Grand View Research (2021): Macadamia Nut Market Size, Share & Trends Analysis Report By Processing (Conventional, Organic), By Product (Raw, Coated, Roasted), By Distribution Channel (Offline, Online), By Region, And Segment Forecasts, 2021–2028