Gelatin

Description

A mixture of proteins prepared by hydrolyzing, via boiling, collagen obtained from skin, ligaments, and tendons. Gelatin is composed of amino acids in the following proportions: glycine (25.5%), proline (18.0%), hydroxyproline (14.1%), glutamic acid (11.4%), alanine (8.7%) along with small amounts of arginine, leucine, and aspartic acid. Gelatin is approved as a food product and is easily digestible. Its production differs from that of animal glue in that raw materials are selected, cleaned, and treated with special care so that the product is cleaner and purer than glue. Gelatin is strongly hydrophilic. In cold water, dried gelatin can absorb up to ten times its weight of water, forming a viscous mass. Adding alum to gelatin produces a harder gel. Potassium chrome alum and formaldehyde (formogelatin) also harden gelatin and make it insoluble. Gelatin is used for photographic film emulsions, sizing, adhesives, inks, encapsulation, and food.

Synonyms and Related Terms

gelatine; glue; Gelfoam; Puragel

Other Properties

Soluble in hot water. Swells in cold water. Precipitated with ethanol.

pH = 4.5-5.0 (aqueous solution)

CAS	9000-70-8
Melting Point	32
Density	1.27
Refractive Index	1.516-1.534

Hazards and Safety

Nontoxic. Powder may be irritating to eyes.

Mallinckrodt Baker: MSDS

Authority

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• Reed Kay, The Painter's Guide To Studio Methods and Materials, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1983

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989

• John S. Mills, Raymond White, The Organic Chemistry of Museum Objects, Butterworth Heineman, London, 2nd ed., 1994

• Encyclopedia Britannica, http://www.britannica.com Comment: "Gelatin." Encyclopædia Britannica. 2004. Encyclopædia Britannica Premium Service. 14 Apr. 2004 .

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000

• Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980

• CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: density=1.27; ref. index = 1.516-1.534