Stabilizing agents lecithin

Preparation of Bearnaise Sauce During the preparation of bearnaise sauce, egg yolks are incorporated into melted butter to stabilize the sauce and avoid separation. The stabilizing agent in the egg yolks is lecithin (phosphatidylcholine). Suggest why this works. 

Lecithins are mainly used in pharmaceutical products as dispersing, emulsifying, and stabilizing agents and are included in intramuscular and intravenous injections, parenteral nutrition formulations, and topical products such as creams and ointments. 

The presence of several colloidal species is an important point that has been overlooked by many scientists. Stabilizing agents are not localized exclusively on the lipid surface but also in the aqueous phase in different forms, which might serve as an alternative location to host the drug molecules. Sometimes the amount of stabilizers exceeds the amount of the lipid phase. For example, stearic acid (as lipid phase), Epikuron 200 (lecithin), and taurocholate have been formulated in the ratio of 3 4 6 [54],... 

The most important excipients in parenteral nutrition solutions are emulsifying agents. Lecithin and phosphatides are mostly used. The emulsifying capacity of phosphatides correlates with their ionisation rate and thereby the pH of the emulsion. The pH also influences the stability of the hpid droplets [58]. If the pH decreases below 3, the droplet surfaces are no longer negatively charged and the droplets coalesce (see Sect. 18.4.1). If necessary, the pH is adjusted with an aqueous solution of sodium hydroxide or hydrochloric acid. 

Chocolate (0.3—0.5% lecithin) lecithin is a wetting agent and emulsifier. It facihtates mixing, saves processiag time and power, saves cocoa butter, stabilizes viscosity, iacreases shelf life, counteracts moisture thickening, and aids release of molded goods (see Chocolate and cocoa). 

As the tocopherols are removed from the lecithin during the extraction process, the de-oiled lecithin has less oxidative stability than the crude product. Also, the surface/volume ratio of the de-oiled lecithin contributes to reduced stability. Mixed soy tocopherols are usually added back at a level of 500 ppm to prevent this. A small percent of an anticaking agent may also be added to ensure that the product remains free-flowing. A free-flowing de-oiled lecithin can be easily added to other products (33). 

Purified soybean lecithin Dispersing agent, emulsifying agent, solubilizer, stabilizer iv... 

The above agents are delivered in a variety of forms. Their compatibility with various solvents (propellants, alcohol, water), liquids (glycerol, polyethylene glycol, oleic acid, sorbitan trioleate, lecithin), and solid (lactose) phase excipients is key to the chemical and physical stability of the products. The Handbook of Pharmaceutical Excipients lists most of these materials.35... 

However, it is not recommended that one use rapidly distributing surfactants exclusively because surfactant mixtures (e.g., Lipoid S75/poloxamer 188 [30] or tyloxapol/lecithin [27]) might lead to lower particle sizes and higher storage stability compared with formulations with only one surfactant. The addition of sodium glycocholate to the aqueous phase as coemulsifying agent decreases the particle size, too [27],... 

Centrolex . [Central Soya] Lecithin granules, deoiled emulsifiers, stabilizers, suspending agents for foods. 

---