Emulsifying agents lecithin

When the emulsion is made the pre-heated condensed milk, fat and emulsifying agent (lecithin) are added to the hot sugar solution. A relatively stable water-fat emulsion can be produced by intensive mixing. 

The fine ground chocolate powder or paste is conveyed into refining equipment where the rest of the cocoa butter, emulsifying agent (lecithin) and the flavourings are added. 

Emulsifying agents (lecithin, mono-glycerides, sucro-glycerides) 0-2... 

Phosphatidic acids are the simplest phosphoacylglycerols and are present only in small amounts in membranes. The most common phosphoacylglycerols in membranes have a second phosphate ester linkage. The alcohols most commonly used to form this second ester group are ethanolamine, choline, and serine. Phosphatidylethanolamines are also called cephalins, and phosphatidylcholines are called lecithins. Used as emulsifying agents, lecithins are added to foods such as mayonnaise to prevent the aqueous and fat components from separating. 

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. 

Lecithin is added to foods such as mayonnaise as an emulsifying agent to prevent the fat and water from sepa rating into two layers... 

Lecithin is widely used as an emulsifying agent, allowing oil and water to mix. It is used in ice creams, salad dressings, and cosmetics, and it is the main ingredient in nonstick cooking sprays. Lecithin is the emulsifier in egg yolks that allows the oil and water to mix to make mayonnaise. 

Emulsifiers. Natural lecithin is one of the most widely used emulsifiers because it is metabolized in the body. However, type I allergic reaction to soybean lecithin emulsified in lipid solutions has been observed [195], Among the synthetic emulsifying agents, block copolymers of polyoxyethylene-polyoxypropylene (poloxamer) have attracted increasing interest for parenteral emulsions. Other examples of emulsifiers commonly found in parenteral formulations are given in Table 9 [190]. 

The phosphoric acid esters of diacyl glycerides, phospholipids, are important constituents of cellular membranes. Lecithins (phosphatidyl cholines) from egg white or soybeans are often added to foods as emulsifying agents or to modify flow characteristics and viscosity. Phospholipids have very low vapor pressures and decompose at elevated temperatures. The strategy for analysis involves preliminary isolation of the class, for example by TLC, followed by enzymatic hydrolysis, derivatization of the hydrolysis products, and then GC of the volatile derivatives. A number of phospholipases are known which are highly specific for particular positions on phospholipids. Phospholipase A2, usually isolated from snake venom, selectively hydrolyzes the 2-acyl ester linkage. The positions of attack for phospholipases A, C, and D are summarized on Figure 9.7 (24). Appropriate use of phospholipases followed by GC can thus be used to determine the composition of phospholipids. 

The lecithin serves as an emulsifying agent that allows the aqueous and lipid phases to be dispersed in each other and increases the time required for phase separation. 

Answer Lecithin (see Fig. 10-14 for structure), an amphipathic molecule, is an emulsifying agent, solubilizing the fat (triacylglycerols) in butter. Lecithin is such a good emulsifying agent that it... 

In addition to being used as a trivial name for phosphatidylcholine, the name lecithin is used for phospholipid fractions relatively rich in phosphatidylcholine, which are widely used as emulsifying agents in food manufacture (E-322). Such preparations typically contain some 40% to 80% phosphatidylcholine, together with a variety of other phospholipids. 

Cakes, cake mixes, pancakes, doughnuts, sweet rolls, fillings, etc. Incorporating lecithin in cake formulations substantially improves the quality of cakes (212). Hydroxylated products that have an intermediate degree of saturation were found to be best. Lecithins have been recommended as emulsifying agents for cake mixes... 

To act as solubilizing, wetting, or emulsifying agents such as Cremophor EL, sodium desoxy-cholate, Polysorbate 20 or 80, PEG 40 castor oil, PEG 60 castor oil, sodium dodecyl sulfate, lecithin, or egg yolk phospholipid. 

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

Why would a phospholipid such as lecithin be a good emulsifying agent for ice cream ... 

The lecithin in the egg yolks serves as an emulsifying agent by forming closed vesicles. The lipids in the butter (frequently triacylglycerols) are retained in the vesicles and do not form a separate phase. 

Milk is an emulsion ofbutterfat droplets in an aqueous mixture of sugars, mineral salts and proteins. Ice cream is another emulsion with a similar composition. The emulsifying agents in both emulsions are proteins with smaller amounts of phospholipids, mainly lecithin. In egg yolk, the emulsifying agents are phospholipids and cholesterol. 

Figure 8.10 Some common foods containing lecithins as emulsifying agents.

Draw the structure of a lecithin. What structural features make lecithin an important commercial emulsifying agent in certain food products ... 

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