Walnut
The drupe-like nut with a rich history and a kernel packed with antioxidants.
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A husk surrounds the walnut's brown, wrinkled shell.[1] Antioxidants are present in the brown seed coat that covers the seed kernels.[1]
Quick Facts
- Species
- Juglans regia (Persian/English walnut)
- Juglans nigra (black walnut)
- Juglans ailantifolia (Japanese walnut/heartnut)
- Known for
- Edible seed
- culinary uses
- health claims
- and historical name 'royal nut'
Facts from the source article.
Biology and range
The three species of walnuts most commonly grown for their seeds are the Persian walnut, the black walnut, and the Japanese walnut.[2] In the northern hemisphere, the walnut harvest season runs from September through November.[1] A membranous partition typically divides the kernel, or meat, into two halves inside the shell.[1] To prevent the oil-rich seed from becoming rancid, antioxidants shield it from atmospheric oxygen.[3]
Hands can be stained and skin irritated by polyphenols and other phytochemicals found in walnut hulls.[4] Juglone, one of seven phenolic compounds identified in walnut husks, makes up 2–4% of their fresh weight.[4] Pedunculagin, an ellagitannin, is another compound found in walnuts.[5] The majority of commercially developed walnut cultivars are hybrids derived from the Persian walnut.[6]
What the specialist sources record
A 1982 fatal crash of a Boeing CH-47 Chinook helicopter in Mannheim, Germany, was traced to an oil port clogged by walnut shell grit, which led to the cessation of using walnut shells for cleaning.[7] For low-abrasive, less-toxic cleaning and blasting tasks outside the aviation sector, crushed walnut shells remain a commercial product.[8] Writing and drawing ink that is durable can be produced from walnut husks.[9] Fabric has been dyed brown using walnut husk pigments, and such pigments were employed for hair dyeing in classical Rome and medieval Europe.[10]
Ground walnut shells are used to make cat litter by a minimum of two companies.[11] In China, large, symmetrically shaped walnut shells, sometimes intricately carved, are known as Wenwan walnuts and are sought-after collectibles.[12]
References
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Grant, "Walnut Tree Harvesting: When Are Walnuts Ready To Pick", Gardening Know How, 19 April 2021 (we also read that source) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Ernest Small, "Top 100 Food Plants", NRC Research Press, 2009, p. 545 (we also read that source) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "Walnut; Agriculture – Transport Information Service", Association for German Insurance, 2010 (we also read that source) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Cosmulescu, "Phenolics of Green Husk in Mature Walnut Fruits", Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 15 June 2010, p. 53–56 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Cerdá, "Metabolism of Antioxidant and Chemopreventive Ellagitannins from Strawberries, Raspberries, Walnuts, and Oak-Aged Wine in Humans: Identification of Biomarkers and Individual Variability", Journal of Agricultural ; Talapatra, "(−)-Regiolone, an α-tetralone from Juglans regia: structure, stereochemistry and conformation", Phytochemistry, January 1988, p. 3929–3932 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "Commodity Profile: English Walnuts", AgMRC, University of California, 2006 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "In Re Air Crash Disaster at Mannheim Germany on 9/11/82. Ursula J. Schoenborn, As Executrix of the Estate of Leonedward Schoenborn, Deceased, v. the Boeing Company. Appeal of the Boeing Company. United States Court of A (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "OSHA fact sheet addresses abrasive blasting hazards"; Cheremisinoff, "Perfluorinated chemicals (PFCs): contaminants of concern", Wiley, 2017, p. 194 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "Black Walnut Ink Workshop", Guild of Natural Science Illustrators, October 2002 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: "The Colors of Invention – How to Dye Fibers Naturally", Smithsonian Museum, 13–16 November 1997; Sherrow, "Encyclopedia of Hair: A Cultural History", Greenwood Publishing Group, 2006, p. 267, 355 (we also read that source) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Parks, "The best natural cat litter we tested with our pets", Insider, 24 October 2022; n.a., "What is the best walnut cat litter", Winston-Salem Journal, 26 May 2023; n.a., "What are the pros of walnut cat litter?", Buffalo News, 26 May 2023; n.a., "What are the cons of walnut cat litter?", SCNow, 26 May 2023 (original not read by us) en.wikipedia.org
- Wikipedia, "Walnut" (CC BY-SA 4.0), which cites: Subler, "Status-conscious investors shell out on great walnuts of China", Reuters, 28 August 2012; Hsieh, "Asian Anthropology Nuts: Beijing folk art connoisseurship in the age of marketization", Asian Anthropology, 13 May 2016 (original not read by us) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Walnut (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Walnut (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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