Macadamia

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Macadamia
Macadamia integrifolia in a plantation

Macadamia integrifolia in a plantation

Systematics
Class : Bedecktsamer (Magnoliopsida)
Eudicotyledons
Order : Silver tree-like (Proteales)
Family : Silver tree family (Proteaceae)
Subfamily : Grevilleoideae
Genre : Macadamia
Scientific name
Macadamia
F. Garbage.

Macadamia is a genus of plants inthe silver tree family (Proteaceae). It is best known for the fruit of the two species Macadamia integrifolia and Macadamia tetraphylla , the seeds of which are called macadamia nuts.

description

Appearance and leaves

Macadamia species grow as trees , sometimes with several trunks, and reach heights of 6 to 18 meters depending on the species. More or less buttress roots are formed.

Spiky leaves of a young Macadamia integrifolia

The leaves are arranged in whorls of three, four or five on the branches, sessile or with a petiole up to 18 mm long. The leathery, elongated leaves have a simple leaf blade and a lanceolate to inverted eilanceolate shape and, depending on the type and age of the specimens, a smooth or spiky-tipped leaf margin. The leaves are up to 25 cm long and 7 cm wide, the tip is pointed to blunt.

Inflorescences and flowers

Unbranched inflorescences of Macadamia integrifolia

The lateral or terminal, pseudo-racemose inflorescences are always simple, in contrast to the species of the genus Lasjia with branched inflorescences, which were previously also classified here . Always two stalked flowers stand together over a more or less early perishable bract . The hermaphroditic flowers are radial symmetry (in Triunia they are slightly zygomorphic ) and fourfold. There are only four bracts and they can be free or intergrown. The cream-colored, cream-brown or pink bracts are belt-shaped with a broadened upper end; they roll back in a circle in the course of the anthesis . There are only four stamens . The stamens are fused with the bracts for part of their length. The connective protrude slightly beyond the anthers . The bare nectar glands are intergrown and form a ring around the ovary around (at Triunia they are free). Each flower contains only one seated, bald to silky hairy, upper carpel . The carpel contains only two orthotropic ovules . The stem-round to slightly square stylus ends in an egg or club-shaped scar.

Fruits and seeds

Smooth-edged leaves of an older specimen of Macadamia integrifolia with fruits

The spherical, initially light green, later dark brown, smooth, leathery, about 2–4 centimeters large drupes (or, according to another view, follicles ) have a finely tapering tip at the top. The fruits only open late along a more or less clear longitudinal seam and usually contain only one nut-brown seed. The pericarp is about 2–5 mm thick and fibrous.

The spherical to broad-egg-shaped stone core, about 1.3-2.5 centimeters in size, seeds (the macadamia nut) has a fibrous, smooth, fine-wrinkled, very hard, shiny, hard-to-crack about 2-5 mm thick seed coat (Testa, Endocarp). The globular embryo consists of two large, cream-colored, hemispherical, sweet, bland or bitter tasting cotyledons ( cotyledons ). It weighs an average of 2.4 to 3.4 grams.

use

Macadamia nuts: left with shell, right roasted

Only two types are economically significant: Macadamia tetraphylla (their nuts have a rough shell and are not suitable for roasting ) and Macadamia integrifolia (with a smooth, but somewhat thinner shell). Only these two kinds produce directly edible nuts; the nuts of the other types are too bitter to be edible, but were historically made usable by the natives of Australia, some Aboriginal tribes, through grinding and prolonged leaching. The nuts growing in the wild are a good source of protein and fat . One of the traditional names from their languages ​​is Kindal Kindal .

Macadamia nuts are considered to be very fine and tasty nuts. In addition, due to the difficult cultivation, the complicated processing and, in particular, the increased demand, they are among the most expensive nuts in the world - hence the name “Queen of Nuts”.

The macadamia oil is also used in the cosmetics industry using, for example, as an exclusive body oil.

Ripening macadamia fruits in Hawaii

Yield and Harvest

The trees bear their first fruits after seven to ten years and can harvest up to 50 kg. The harvest time is between March and September and is carried out in several harvest cycles due to the different degrees of ripeness of the nuts.

The nuts ripen on the trees and are harvested from the ground. They are then left to be well ventilated for a few weeks or months in order to reduce their water content from the original 30 percent to around 1.5 to 2 percent. This makes them easier to crack. The nuts are almost exclusively sold peeled or processed, as their shells are very hard and relatively thick. Most conventional nutcrackers cannot open it; Special spindle nut crackers are best .

Nutritional value and ingredients

Shelled, roasted, and salted macadamia nuts as they are commercially available

Nutritional values ​​per 100 g (edible, natural, without salt)

Toxicity

Macadamia nuts are poisonous to cats and dogs . The mechanisms of action are unknown.

In dogs, the effects after ingesting macadamia nuts in quantities above 2 g / kg body weight initially appear as lethargy and weakness, especially of the hind legs. Vomiting, stance and gait instability ( ataxia ) as well as muscle tremors and increased body temperature can also occur. Most dogs recover from intoxication within 24 hours, regardless of treatment, and recover completely after 48 hours.

Cats may experience muscle tremors, lameness, joint stiffness, and high fever.

Home, endangerment and growing areas

The origin of all macadamia species is found in Queensland and the bordering New South Wales in eastern Australia . They occur exclusively in a subtropical area within an approximately 500 km long strip on the east coast of the country.

Despite the high demands of the not very vigorous trees, today the growing areas include Australia, Hawaii (largest producer), New Zealand , South Africa , Malawi , Kenya , Israel , Brazil , California , Guatemala , Paraguay and Bolivia . Macadamia is the only food plant of Australian origin that is traded to a significant extent worldwide.

At least the species Macadamia tetraphylla and Macadamia integrifolia are now considered endangered in New South Wales .

Systematics and botanical history

Illustration of Macadamia ternifolia

Around 1857, the first type was Macadamia ternifolia by the botanist Ferdinand von Mueller and Walter Hill , director of the Botanical Gardens of Brisbane , in a forest on the Pine River discovered the Moreton Bay. The generic name Macadamia honors the scientist friend John Macadam (1827-1865). The genus Macadamia was founded in 1857 by Ferdinand von Müller in Account of some new Australian plants in Transactions and Proceedings of the Philosophical Institute of Victoria 2, p. 72 with the first description of the type species Macadamia ternifolia F. Muell. set up.

The genus Macadamia belongs to the tribe Macadamieae in the subfamily Grevilleoideae within the family Proteaceae . Some species that were previously classified in this genus were placed in other equally species-poor genera, for example Lasjia PHWeston & ARMast (five species), Triunia , Floydia .

Since 2008 only four types have been differentiated (compared to up to ten macadamia types before ):

literature

  • CL Gross: Flora of Australia Online : Macadamia : Full text online. (If the direct link doesn't work at the moment , you can also try to enter the taxon in the search mask ) (sections Description and Distribution).
  • Austin R. Mast, Crystal L. Willis, Eric H. Jones, Katherine M. Downs, Peter H. Weston: A smaller Macadamia from a more vagile tribe: inference of phylogenetic relationships, divergence times, and diaspore evolution in Macadamia and relatives ( tribe Macadamieae; Proteaceae). In: American Journal of Botany. Vol. 95, No. 7, 2008, p. 865, full text online. doi : 10.3732 / ajb.0700006 (section systematics, description and distribution).

Individual evidence

  1. ↑ a b c d C. L. Gross: Flora of Australia Online : Macadamia : Excerpt from the Flora of Australia work. 1995. Retrieved June 12, 2013.
  2. ^ Leonard Cronin: Australian Flora. Rev. ed., Reed Books, 1997, ISBN 0-7301-0504-0 , p. 155.
  3. ↑ Frederic Rosengarten Jr .: The Book of Edible Nuts. Dover Publ., 1984, ISBN 0-486-43499-0 , p. XVII.
  4. ↑ Sabine Krist: Lexicon of vegetable fats and oils. 2nd edition, Springer, 2013, ISBN 978-3-7091-1004-1 , p. 434.
  5. ↑ a b c d A. R. Mast, CL Willis, EH Jones, KM Downs, PH Weston: A smaller Macadamia from a more vagile tribe: inference of phylogenetic relationships, divergence times, and diaspore evolution in Macadamia and relatives (tribe Macadamieae; Proteaceae) . In: American Journal of Botany. Vol. 95, No. 7, 2008, p. 865, full text online. doi : 10.3732 / ajb.0700006 .
  6. ↑ Macadamia on hort.purdue.edu, accessed on August 10, 2017.
  7. ↑ Erin Kelly Monaghan: Chemical Composition and Protein Antigenicity Almond (Prunus Dulcis) and Macadamia Nut (Macadamia Integrifolia) Seeds. Dissertation, Florida State University, 2008, online (PDF; 6.65 MB).
  8. ↑ Macadamia nuts at eatsmarter.de, accessed on May 1, 2016.
  9. ↑ The Macadania tree at australian-macadamias.de, accessed on May 1, 2016.
  10. ^ The Journey of the Australian Macadamia Australian Macadamia Society Ltd, January 15, 2014.
  11. ↑ Nutritional Values Macadamia at Delphiorganic.com, accessed on July 5, 2020
  12. ↑ S. Handl, C. Iben: Foodstuffs toxic to small animals - a review ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.fecava.org archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF). In: Companion Animal Practice. Volume 20, 2010, p. 40.
  13. ^ Treacherous Treats - Macadamia Nuts , Christine Allen, October 2001.
  14. ↑ David Brunner, Sam Stall: The Cat. Sanssouci, Munich / Vienna 2005, ISBN 978-3-7254-1357-7 , p. 181.
  15. ^ Macadamia at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed June 12, 2013.
  16. ^ Macadamia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 12, 2013.
  17. ↑ APNI = Australian Plant Name Index. Center for Plant Biodiversity Research, Australian Government. Retrieved June 12, 2013.
  18. ↑ a b c Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold: The great pikeperch. Encyclopedia of Plant Names. Volume 2: Types and varieties , Eugen Ulmer, Stuttgart (Hohenheim) 2008, ISBN 978-3-8001-5406-7 .

Web links

Commons : Macadamia  - collection of images, videos and audio files