The Macadamia Nut—Australia’s Native Delicacy
BOTANIST Walter Hill watched his young assistant in horror. The boy had just eaten nuts from a newly discovered species of tree growing in the subtropical rain forests of southeast Queensland, Australia. Hill had heard that the nuts were poisonous. But the lad neither became ill nor dropped dead. Instead, he found the nuts to be delicious. So Hill tried one himself and agreed. Soon thereafter he began distributing macadamia seedlings to friends and botanists around the world.*
Today, some 150 years later, macadamia nuts are popular worldwide—and for good reason. The journal Chronica Horticulturae explains: “The macadamia is considered one of the world’s finest gourmet nuts because of its unique, delicate flavour, its fine crunchy texture, and rich creamy colour.” Little wonder that macadamia nuts are Australia’s most successful indigenous food crop!
A Tough Nut to Crack
Evergreen macadamia trees flourish along Australia’s subtropical east coast. Two of the nine species produce edible nuts, which consist of a fibrous outer husk; a tan, spherical shell, and a marble-size, cream-colored kernel.
The tough shell, however, is hard to crack.* The Aborigines used rocks. Pioneer orchardist John Waldron used a hammer and anvil. In fact, with these simple tools, he cracked open about eight million nuts over a period of 50 years. Could machines do the job? Early designs were unacceptable because they tended to damage the kernel. In time, however, more effective machines were built.
Another problem involved reproduction. When planted, nuts from good trees often produced poor quality offspring. And efforts at grafting failed. Faced with these difficulties, commercial cultivation stalled—that is, until the Hawaiians tackled the problem. They made the needed breakthroughs. As a result, they were soon supplying 90 percent of the world’s macadamia nuts. Not surprisingly, they came to be called Hawaiian nuts.
Then, in the 1960’s, Australian growers “took on the macadamia as a serious commercial crop,” applying the lessons learned in Hawaii. As a result, the local industry blossomed to the point that Australia now produces about 50 percent of the world’s macadamia nuts. They are also grown in Africa, Asia, and Central America.
A Visit to an Australian Farm
Awake! visited Andrew, who has a macadamia farm near the town of Lismore, New South Wales. “We plant different macadamia varieties every few rows to encourage cross-pollination,” explained Andrew. Awake! learned that about 80 percent of the many millions of trees planted in Australia are proved varieties selected by Hawaiian breeders. However, Australian breeders are now using genetic material from wild macadamias to produce improved local varieties.
Looking at the trees, we see hundreds of nuts dangling like little balls in the thick foliage. The nuts mature over six months and then fall to the ground. We notice that some of the fallen nuts have holes. “Rats can chew through a shell in eight seconds,” said Andrew. “Wild pigs also love macadamia nuts.” Further along the row, Andrew pauses to kick a half-buried nut free from the dirt. “That’s three cents saved,” he says with a grin. Many farmers harvest the nuts by using a specially designed machine with a drum and short plastic fingers that collect fallen nuts. The nuts are then husked and sorted at the farm, after which they are delivered to a factory to be shelled, graded, and shipped to buyers.
Tasty and Healthful!
As we finish our tour, we munch on a handful of kernels—their rich, creamy flavor leaving us smacking our lips. But are macadamia nuts healthful? The oil content of the nut (largely monounsaturated oil, or good oil) “regularly exceeds 72%, which is the highest for any oil-yielding nut,” says a government fact sheet on macadamia-nut culture. According to recent studies, modest consumption can actually reduce harmful low-density cholesterol and triglycerides and lower high blood pressure.
People enjoy macadamia nuts in chocolate candy, gourmet cookies, or premium ice cream. Others prefer them roasted, salted, or simply straight from the shell. Whatever their preference, most people come back for more.
Years earlier, explorers Cunningham (1828) and Leichhardt (1843) collected macadamia nuts, but their specimens were placed in storage and not described. In 1857, a colleague of Hill’s, Melbourne botanist Ferdinand von Mueller, named the genus Macadamia after his good friend Dr. John Macadam.
Crushed macadamia-nut shell is so hard that it makes an excellent industrial abrasive.
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SHELLS FUEL A POWER PLANT
Rock-hard macadamia-nut shells have a calorific, or fuel, value close to that of brown coal. Thus, an Australian energy provider is using waste shells to generate electricity for both the nut processing plant and the electricity grid. The plant is Australia’s first waste-to-energy project, and its output may increase considerably as more growers provide fuel.
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Australia’s growers plant thousands of new trees every year
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All photos pages 22 and 23: Australian Macadamia Society