Difference between revisions of "Egg yolk"
Jump to navigation
Jump to search
(username removed) |
|||
| (5 intermediate revisions by 3 users not shown) | |||
| Line 1: | Line 1: | ||
== Description == | == Description == | ||
| − | The interior yellow, spherical portion of a bird [ | + | The interior yellow, spherical portion of a bird [[egg]]. The yolk from a hen egg is composed of about 50% [[water]], 15% [[protein]], 22% [[lipid|lipids]], 9% [[lecithin]] and 3% other materials. The distribution of major [[amino acid|amino acids]] is: [[glutamic acid]] (15.0%), aspartic acid (11.5%), [[leucine]] (9.2%), [[lysine]] (5.7%), valine (6.4%), arginine (5.5%), [[alanine]] (5.6%), isoleucine (5.1%) and serine (9.1%) with no measurable amounts of [[hydroxyproline]] (Mills and White 1994). Egg yolk is a natural emulsion that dries into a strong, water-insoluble film, first by the evaporation of water, then by the hardening of the lipids (Gettens and Stout, 1966). When used traditionally as a paint medium, the pure egg yolk is carefully separately from the egg white, then rolled back and forth in the hands to dry the surface of the sac. The sac is pierced to release its contents which are then ground with pigments. Vinegar was sometimes added as a preservative. |
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| Line 9: | Line 9: | ||
[[[SliderGallery rightalign|MFA- Egg yolk (partially dried).jpg~FTIR]]] | [[[SliderGallery rightalign|MFA- Egg yolk (partially dried).jpg~FTIR]]] | ||
| − | == | + | == Physical and Chemical Properties == |
| − | Soluble in water after drying. Insoluble in water after heating. | + | * Soluble in water after drying. |
| + | * Insoluble in water after heating. | ||
| − | == | + | == Resources and Citations == |
| − | + | * John S. Mills, Raymond White, ''The Organic Chemistry of Museum Objects'', Butterworth Heineman, London, 2nd ed., 1994. | |
| − | + | * R. J. Gettens and G.L. Stout, ''Painting Materials, A Short Encyclopaedia'', Dover Publications, New York, 1966. | |
| − | |||
| − | * R. J. Gettens | ||
* Hermann Kuhn, ''Conservation and Restoration of Works of Art and Antiquities'', Butterworths, London, 1986 | * Hermann Kuhn, ''Conservation and Restoration of Works of Art and Antiquities'', Butterworths, London, 1986 | ||
| − | + | * ''Encyclopedia Britannica'', http://www.britannica.com Comment: "Yolk." [Accessed 14 Apr. 2004]. | |
| − | |||
| − | * ''Encyclopedia Britannica'', http://www.britannica.com Comment: "Yolk." | ||
[[Category:Materials database]] | [[Category:Materials database]] | ||
Latest revision as of 13:35, 16 August 2020
Description
The interior yellow, spherical portion of a bird Egg. The yolk from a hen egg is composed of about 50% Water, 15% Protein, 22% lipids, 9% Lecithin and 3% other materials. The distribution of major amino acids is: Glutamic acid (15.0%), aspartic acid (11.5%), Leucine (9.2%), Lysine (5.7%), valine (6.4%), arginine (5.5%), Alanine (5.6%), isoleucine (5.1%) and serine (9.1%) with no measurable amounts of Hydroxyproline (Mills and White 1994). Egg yolk is a natural emulsion that dries into a strong, water-insoluble film, first by the evaporation of water, then by the hardening of the lipids (Gettens and Stout, 1966). When used traditionally as a paint medium, the pure egg yolk is carefully separately from the egg white, then rolled back and forth in the hands to dry the surface of the sac. The sac is pierced to release its contents which are then ground with pigments. Vinegar was sometimes added as a preservative.
Synonyms and Related Terms
deutoplasm
.jpg)
Physical and Chemical Properties
- Soluble in water after drying.
- Insoluble in water after heating.
Resources and Citations
- John S. Mills, Raymond White, The Organic Chemistry of Museum Objects, Butterworth Heineman, London, 2nd ed., 1994.
- R. J. Gettens and G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966.
- Hermann Kuhn, Conservation and Restoration of Works of Art and Antiquities, Butterworths, London, 1986
- Encyclopedia Britannica, http://www.britannica.com Comment: "Yolk." [Accessed 14 Apr. 2004].