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You will never again throw away an egg shell
You will never again throw away an egg shell
Published: 2016/12/13
Channel: EVA FOX. Home Remedies for Health.
Eggshell Montage | Best Plays Of 2016 (League Of Legends)
Eggshell Montage | Best Plays Of 2016 (League Of Legends)
Published: 2016/08/24
Channel: zeko
How To Make Eggshell Calcium
How To Make Eggshell Calcium
Published: 2014/04/10
Channel: TheCrunchyHousewife
Best of Eggshell | League of Legends
Best of Eggshell | League of Legends
Published: 2016/06/12
Channel: JUBEL
Ladies Montage - Best Of Eggshell (League Of Legends)
Ladies Montage - Best Of Eggshell (League Of Legends)
Published: 2016/12/19
Channel: ToA
Alev Lenz - Eggshell
Alev Lenz - Eggshell
Published: 2016/11/10
Channel: AlevLenzVEVO
You Can Get Rid Cavities By Using Egg Shells.  Find It How!
You Can Get Rid Cavities By Using Egg Shells. Find It How!
Published: 2016/06/19
Channel: Trending Updates
Egg Shell Science Experiment - Dissolves in Vinegar
Egg Shell Science Experiment - Dissolves in Vinegar
Published: 2016/05/13
Channel: DaveHax
Use Eggshells to Eliminate Pain Bone and Joint, Grow Hair and Nails
Use Eggshells to Eliminate Pain Bone and Joint, Grow Hair and Nails
Published: 2016/07/29
Channel: Article-TUBE2
EGG HAIR MASK FOR HAIR GROWTH | EGG SHELL HAIR MASK FOR EXTREME HAIR GROWTH SOFT SHINY SILKY HAIR
EGG HAIR MASK FOR HAIR GROWTH | EGG SHELL HAIR MASK FOR EXTREME HAIR GROWTH SOFT SHINY SILKY HAIR
Published: 2016/10/14
Channel: Home Remedies Soundarya Gharelu Upachar
Witchcraft and Eggshells
Witchcraft and Eggshells
Published: 2016/10/07
Channel: TheLadygravedancer
How to make egg shell calcium
How to make egg shell calcium
Published: 2013/03/13
Channel: EastWest Healing
Eggshell Planters, Gardening with Kids!
Eggshell Planters, Gardening with Kids!
Published: 2017/03/31
Channel: Learn To Grow
This is why you might want to start eating eggshells
This is why you might want to start eating eggshells
Published: 2017/02/09
Channel: Tech Insider
2 Min. Tip: How We Use Eggshells in Our Garden (Eggshell Calcium)
2 Min. Tip: How We Use Eggshells in Our Garden (Eggshell Calcium)
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Channel: OneYardRevolution | Frugal & Sustainable Organic Gardening
How To Dissolve an Eggshell
How To Dissolve an Eggshell
Published: 2015/01/19
Channel: HowToBasic
You will never throw away an egg shell when you know all this things!
You will never throw away an egg shell when you know all this things!
Published: 2017/02/13
Channel: Robert von Rotz Roy
Eggshell: for Teeth Cavities
Eggshell: for Teeth Cavities
Published: 2016/08/23
Channel: Ryan Taylor
How to Add TEXTURE with EGGSHELLS (part 1 of 2)
How to Add TEXTURE with EGGSHELLS (part 1 of 2)
Published: 2014/12/22
Channel: Amy Pearce
Eggshell protection powder :)
Eggshell protection powder :)
Published: 2013/05/30
Channel: WhiteRaven Witch's Lair
Eggshell Montage - Best of Eggshell 2016
Eggshell Montage - Best of Eggshell 2016
Published: 2016/11/17
Channel: Nel Peace HD ŀ Montages League of Legends
You Will Never Throw Away Eggshells After Watching This
You Will Never Throw Away Eggshells After Watching This
Published: 2017/04/13
Channel: Natural Ways
HOW TO CARVE Egg Shell Engraving ART
HOW TO CARVE Egg Shell Engraving ART
Published: 2016/07/12
Channel: Artsmith
►The Egg Shell Pendant - Craft Tutorial 15
►The Egg Shell Pendant - Craft Tutorial 15
Published: 2012/01/13
Channel: BeyondBracelets
Egg Shell Engraving Eggshell Carving Goose Egg 400xs Power Carver
Egg Shell Engraving Eggshell Carving Goose Egg 400xs Power Carver
Published: 2015/09/03
Channel: scmsystems
how to make angry birds from egg shell | Cory channel
how to make angry birds from egg shell | Cory channel
Published: 2017/06/21
Channel: Cory
Top 10 Uses of Eggshells - video
Top 10 Uses of Eggshells - video
Published: 2016/07/19
Channel: Gyan Bato
Adult Jazz - Eggshell
Adult Jazz - Eggshell
Published: 2016/04/04
Channel: Adult Jazz
Eggshell treatment http://faceyogamethod.com/ - Face Yoga Method
Eggshell treatment http://faceyogamethod.com/ - Face Yoga Method
Published: 2014/06/05
Channel: Face Yoga Method
TOMATO CARE | EGG SHELL PUREE  |  NPK-CA |  PEST CONTROL | IV ORGANIC PLANT GUARD
TOMATO CARE | EGG SHELL PUREE | NPK-CA | PEST CONTROL | IV ORGANIC PLANT GUARD
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Channel: IV Organic
Egg Shell Sticker Wooden Panel Test
Egg Shell Sticker Wooden Panel Test
Published: 2012/08/17
Channel: Egg Shell Stickers
This Is The 6 Benefits Of Eggshell Egg
This Is The 6 Benefits Of Eggshell Egg
Published: 2015/11/15
Channel: GHIACOM TV
Stop Cavities DIY Eggshell Toothpaste
Stop Cavities DIY Eggshell Toothpaste
Published: 2017/05/23
Channel: QuasiLuminous
How to make a Penguin Couple from Egg shell
How to make a Penguin Couple from Egg shell
Published: 2014/06/22
Channel: Brainergiser
How to Prepare Eggshells for Use in the Garden: Vinegar & Blossom End Rot - The Rusted Garden 2014
How to Prepare Eggshells for Use in the Garden: Vinegar & Blossom End Rot - The Rusted Garden 2014
Published: 2013/12/29
Channel: Gary Pilarchik
Egg shell mosaic - Mosaic en coquille d
Egg shell mosaic - Mosaic en coquille d'oeuf - Cáscara de huevo mosaico
Published: 2015/06/02
Channel: kativilaga
9.3.3 Safari Exploit + Eggshell Demonstration
9.3.3 Safari Exploit + Eggshell Demonstration
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Channel: Lucas Jackson
Egg Shell Mosaic
Egg Shell Mosaic
Published: 2013/02/07
Channel: saraswati delhi
Autechre - Eggshell. HQ
Autechre - Eggshell. HQ
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Channel: ElectronicHQ
DIY: Egg Shell Decorated Wine Bottle
DIY: Egg Shell Decorated Wine Bottle
Published: 2015/01/26
Channel: MonkeyBusiness nv
DIY Eggshell Mosaic Plate Wall Decor
DIY Eggshell Mosaic Plate Wall Decor
Published: 2016/03/06
Channel: Troom Troom
Eggshell Carving Art  █▬█ █ ▀█▀
Eggshell Carving Art █▬█ █ ▀█▀
Published: 2015/12/16
Channel: Old Tires Planters Tire Painting
How to Make Egg Shell DIY Candles - Cool Craft Idea
How to Make Egg Shell DIY Candles - Cool Craft Idea
Published: 2015/03/23
Channel: Red Ted Art
DIY Fish using egg shell ; craft for kids
DIY Fish using egg shell ; craft for kids
Published: 2016/09/11
Channel: simple
how to make  penguin using egg ; creative use of egg shell, craft for kids
how to make penguin using egg ; creative use of egg shell, craft for kids
Published: 2016/09/02
Channel: simple
Dissolving Egg Shell With CO2
Dissolving Egg Shell With CO2
Published: 2015/10/29
Channel: Cody'sLab
Egg Shell Crystals
Egg Shell Crystals
Published: 2015/04/04
Channel: dartofscience
Shed an eggshell in seconds.
Shed an eggshell in seconds.
Published: 2017/04/18
Channel: The Grommet
Egg Shell Seed Starter
Egg Shell Seed Starter
Published: 2014/05/11
Channel: Survival HT
Demonstration of flat versus eggshell / satin / semi-gloss paint
Demonstration of flat versus eggshell / satin / semi-gloss paint
Published: 2014/09/05
Channel: Marcus Burke
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WIKIPEDIA ARTICLE

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A broken wild bird eggshell

An eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats. Bird eggshells contain calcium carbonate and dissolve in various acids, including the vinegar used in cooking. While dissolving, the calcium carbonate in an eggshell reacts with the acid to form carbon dioxide.[1]

Diversity[edit]

Insect eggs[edit]

Butterfly embryo / caterpillar visible through transparent eggshell

Insects and other arthropods lay a variety of styles and shapes of eggs. Some have gelatinous or skin-like coverings, others have hard eggshells. Softer shells are mostly protein. It may be fibrous or quite liquid. Some arthropod eggs do not actually have shells, rather, their outer covering is actually the outermost embryonic membrane, the choroid, which serves to protect inner layers. The choroid itself can be a complex structure, and it may have different layers within it. It may have an outermost layer called an exochorion. Eggs which must survive in dry conditions usually have hard eggshells, made mostly of dehydrated or mineralized proteins with pore systems to allow respiration. Arthropod eggs can have extensive ornamentation on their outer surfaces.

Fish, amphibian and reptile eggs[edit]

Fish and amphibians generally lay eggs which are surrounded by the extraembryonic membranes but do not develop a shell, hard or soft, around these membranes. Some fish and amphibian eggs have thick, leathery coats, especially if they must withstand physical force or desiccation. These type of eggs can also be very small and fragile.

While many reptiles lay eggs with flexible, calcified, eggshells, there are some that lay hard eggs. Eggs laid by snakes generally have leathery shells which often adhere to one another. Depending on the species, turtles and tortoises lay hard or soft eggs. Several species lay eggs which are nearly indistinguishable from bird eggs.

Bird eggs[edit]

Anatomy of an egg labeled.jpg

The bird egg is a fertilized gamete (or, in the case of some birds, such as chickens, possibly unfertilized) located on the yolk surface and surrounded by albumen, or egg white. The albumen in turn is surrounded by two shell membranes (inner and outer membranes) and then the eggshell. The chicken eggshell is 95-97% calcium carbonate crystals, which are stabilized by a protein matrix.[2][3][4] Without the protein, the crystal structure would be too brittle to keep its form and the organic matrix is thought to have a role in deposition of calcium during the mineralization process.[5][6][7] The structure and composition of the avian eggshell serves to protect the egg against damage and microbial contamination, prevention of desiccation, regulation of gas and water exchange for the growing embryo, and provides calcium for embryogenesis. Eggshell formation requires gram amounts of calcium being deposited within hours, which must be supplied via the hen’s diet.[4]

Brown chicken egg with irregular calcification
Structure revealed by light

The fibrous chicken shell membranes are added in the proximal (white) isthmus of the oviduct.[4] In the distal (red) isthmus mammillae or mammillary knobs are deposited on the surface of the outer membrane in a regular array pattern.[8][9] The mammillae are proteoglycan-rich and are thought to control calcification. In the shell gland (similar to a mammalian uterus), mineralization starts at the mammillae. The shell gland fluid contains very high levels of calcium and hydrogen carbonate. The thick calcified layer of the eggshell forms in columns from the mammillae structures, and is known as the palisade layer. Between these palisade columns are narrow pores that traverse the eggshell and allow gaseous exchange. The cuticle forms the final, outer layer of the eggshell.[10]

While the bulk of eggshell is made of calcium carbonate, it is now thought that the protein matrix has an important role to play in eggshell strength.[11] These proteins affect crystallization, which in turn affects the eggshell structure. Moreover, the concentration of eggshell proteins decreases over the life of the laying hen, as does eggshell strength.

In an average laying hen, the process of shell formation takes around 20 hours. Pigmentation is added to the shell by papillae lining the oviduct, coloring it any of a variety of colors and patterns depending on species. Since eggs are usually laid blunt end first, that end is subjected to most pressure during its passage and consequently shows the most color.

Environmental issues[edit]

The US food industry generates 150,000 tons of shell waste a year.[12] The disposal methods for waste eggshells are 26.6% as fertilizer, 21.1% as animal feed ingredients, 26.3% discarded in municipal dumps, and 15.8% used in other ways.[13] Many landfills are unwilling to take the waste because the shells and the attached membrane attract vermin.[citation needed] Together the calcium carbonate eggshell and protein rich membrane are useless.[14] Recent inventions have allowed for the egg cracking industry to separate the eggshell from the eggshell membrane. The eggshell is mostly made up of calcium carbonate and the membrane is valuable protein. When separated both products have an array of uses.

Mammal eggs[edit]

Monotremes, egg-laying mammals, lay soft-shelled eggs similar to those of reptiles. The shell is deposited on the egg in layers within the uterus. The egg can take up fluids and grow in size during this process, and the final, most rigid layer is not added until the egg is full-size.

Egg teeth[edit]

Hatching birds, amphibian and egg-laying reptiles have an egg-tooth used to start an exit hole in the hard eggshell.[15][16]

See also[edit]

References[edit]

  1. ^ "Q & A: Eggshells in Vinegar - What happened? | Department of Physics | University of Illinois at Urbana-Champaign". Van.physics.illinois.edu. 2007-10-22. Retrieved 2012-10-16. 
  2. ^ Arias, J. L.; Fernandez, M. S. (2001). "Role of extracellular matrix molecules in shell formation and structure". World's Poultry Science Journal. 57: 349–357. doi:10.1079/WPS20010024. 
  3. ^ Nys, Yves; Gautron, Joël; Garcia-Ruiz, Juan M.; Hincke, Maxwell T. (2004). "Avian eggshell mineralization: biochemical and functional characterization of matrix proteins". Comptes Rendus Palevol. 3: 549–62. doi:10.1016/j.crpv.2004.08.002. 
  4. ^ a b c Hunton, P (2005). "Research on eggshell structure and quality: an historical overview". Revista Brasileira de Ciência Avícola. 7: 67–71. doi:10.1590/S1516-635X2005000200001. 
  5. ^ Romanoff, A.L., A.J. Romanoff (1949) The avian egg. New York, Wiley.
  6. ^ Burley, R.W., D.V. Vadehra (1989) The Avian Egg: Chemistry and Biology. New York, Wiley.
  7. ^ Lavelin, I; Meiri, N; Pines, M (2000). "New insight in eggshell formation". Poultry science. 79 (7): 1014–7. PMID 10901204. doi:10.1093/ps/79.7.1014. 
  8. ^ Wyburn, GM; Johnston, HS; Draper, MH; Davidson, MF (1973). "The ultrastructure of the shell forming region of the oviduct and the development of the shell of Gallus domesticus". Quarterly journal of experimental physiology and cognate medical sciences. 58 (2): 143–51. PMID 4487964. 
  9. ^ Fernandez, MS; Araya, M; Arias, JL (1997). "Eggshells are shaped by a precise spatio-temporal arrangement of sequentially deposited macromolecules". Matrix biology. 16 (1): 13–20. PMID 9181550. doi:10.1016/s0945-053x(97)90112-8. 
  10. ^ "The Egg-Shell Microstructure Studied by Powder Diffraction". Xray.cz. Retrieved 2012-10-16. 
  11. ^ http://ict.udg.co.cu/FTPDocumentos/Literatura%20Cientifica/Maestria%20Nutricion%20Animal/6.%20EVENTOS%20RELEVANTES/XVII%20Congreso%20Avicultura/confs/hunton1.htm. Retrieved February 2, 2011.  Missing or empty |title= (help)[dead link]
  12. ^ Hecht J: Eggshells break into collagen market. New Scientist 1999, 161:6-6.
  13. ^ Daengprok W, Garnjanagoonchorn W, Mine Y: Fermented pork sausage fortified with commercial or hen eggshell calcium lactate. Meat Science 2002, 62:199-204.
  14. ^ Wei Z, Li B, Xu C: Application of waste eggshell as low-cost solid catalyst for biodiesel production [electronic resource]. Bioresource technology 2009, 100:2883-2885.
  15. ^ "What is Egg Shell Quality and How to Preserve It". Ag.ansc.purdue.edu. Retrieved 2012-10-16. 
  16. ^ Nys, Yves; Gautron, Joël; Garcia-Ruiz, Juan M.; Hincke, Maxwell T. "Avian eggshell mineralization: biochemical and functional characterization of matrix proteins" (PDF). Comptes Rendus Palevol. 3 (6-7): 549–562. doi:10.1016/j.crpv.2004.08.002. 

Further reading[edit]

External links[edit]

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