Egg lecithin is a type of lecithin, a group of compounds primarily containing , that is derived from eggs.
Discovery
Egg lecithin was first isolated in 1846 by the French chemist and pharmacist Theodore Gobley.
[Gobley (1846) "Recherches chimiques sur le jaune d'œuf" (Chemical researches on egg yolk), Journal de Pharmacie et de Chemie, series 3, vol. 9, pages 81-91; on page 84)] Gobley originally isolated lecithin from
egg yolk—λέκιθος (
lekithos) is 'egg yolk' in
ancient Greek—and established the complete chemical formula of phosphatidylcholine in 1874.
Biology
Phosphatidylcholine a major component of egg lecithin, occurs in all cellular organisms, being one of the important components of the phospholipid portion of the
cell membrane. Other components include phosphatidylethanolamine and
sphingomyelin.
Production
Egg lecithin is usually extracted chemically using
ethanol,
acetone,
petroleum ether but not
benzene or
hexane due to restrictions on residual solvents by the pharmaceutical regulations.
[ ICH Topic Q3C (R4) Impurities: Guideline for Residual Solvents] It is an emulsifier, especially for
parenteral use since it does not need to be metabolized. In aqueous solution, its phospholipids can form either
, bilayer sheets,
, or lamellar structures, depending on hydration and temperature. This results in a type of
surfactant that is usually classified as
amphipathic.
Commercial egg lecithin, specified in the United States National Formulatory (USP/NF) as used by pharmaceutical companies, is a highly purified mixture of , devoid of , cholesterol, or .
Properties and applications
Egg lecithin has
emulsion and
lubricant properties, and is a
surfactant. It can be totally integrated into the cell membrane in humans, so does not need to be metabolized and is well tolerated by humans and non
toxic when ingested; some synthetic
can only be excreted via the
.
Applications include:
-
In the pharmaceutical industry, it acts as a wetting, stabilizing agent and a choline enrichment carrier, helps in emulsifications and encapsulation, and is a good dispersing agent. It can be used in manufacture of intravenous fat infusions and for therapeutic use. Examples of intravenous applications are propofol for anesthesia, NSAID drugs,
etc.
-
In the cosmetics industry, it is used to produce stable O/W emulsions for cosmetic compositions or pharmaceutical excipients
[ United States Patent No. 4481185, Grollier, et.al.]
Egg lecithin is approved by the
United States Food and Drug Administration with the status "generally recognized as safe"
[
]
target="_blank" rel="nofollow"> Egg-derived phospholipids as an ingredient in term and preterm infant formula, Food and Drug Administration, USA and listed in the compendium.
Compatibility with special diets
Egg-derived lecithin is not usually a concern for those allergic to eggs since commercially available food grade egg lecithin is devoid of allergy-causing egg proteins. Egg lecithin is not a concern for those on low-
cholesterol diets, because the lecithin found in eggs markedly inhibits the absorption of the cholesterol contained in eggs.
[Unisci.com, Why Eggs Don't Contribute Much Cholesterol To Diet.]
External links