Properties and applications

Lecithins have emulsification and lubricant properties, and are a surfactant. They can be completely metabolized (see inositol) by humans, so are well tolerated by humans and nontoxic when ingested; some other emulsifiers can only be excreted via the kidneys.

The major components of commercial soybean-derived lecithin are:

• 33–35% Soybean oil
• 20–21% Phosphatidylinositols
• 19–21% Phosphatidylcholine
• 8–20% Phosphatidylethanolamine
• 5–11% Other phosphatides
• 5% Free carbohydrates
• 2–5% Sterols
• 1% Moisture

Lecithin is used for applications in human food, animal feed, pharmaceuticals, paints, and other industrial applications.

Applications include:

• In the pharmaceutical industry, it acts as a wetting agent, stabilizing agent and a choline enrichment carrier, helps in emulsification and encapsulation, and is a good dispersing agent. It can be used in manufacture of intravenous fat infusions and for therapeutic use.
• In animal feed, it enriches fat and protein and improves pelletization.
• In the paint industry, it forms protective coatings for surfaces with painting and printing ink, has antioxidant properties, helps as a rust inhibitor, is a colour-intensifying agent, catalyst, conditioning aid modifier, and dispersing aid; it is a good stabilizing and suspending agent, emulsifier, and wetting agent, helps in maintaining uniform mixture of several pigments, helps in grinding of metal oxide pigments, is a spreading and mixing aid, prevents hard settling of pigments, eliminates foam in water-based paints, and helps in fast dispersion of latex-based paints.
• Lecithin also may be used as a release agent for plastics, an antisludge additive in motor lubricants, an antigumming agent in gasoline, and an emulsifier, spreading agent, and antioxidant in textile, rubber, and other industries.

Food additive

The nontoxicity of lecithin leads to its use with food, as an additive or in food preparation. It is used commercially in foods requiring a natural emulsifier or lubricant.

In confectionery, it reduces viscosity, replaces more expensive ingredients, controls sugar crystallization and the flow properties of chocolate, helps in the homogeneous mixing of ingredients, improves shelf life for some products, and can be used as a coating. In emulsions and fat spreads, such as margarines with a high fat content of more than 75%, it stabilizes emulsions, reduces spattering (splashing and scattering of oil droplets) during frying, improves texture of spreads and flavor release. In doughs and baking, it reduces fat and egg requirements, helps even out distribution of ingredients in dough, stabilizes fermentation, increases volume, protects yeast cells in dough when frozen, and acts as a releasing agent to prevent sticking and simplify cleaning. It improves wetting properties of hydrophilic powders (such as low-fat proteins) and lipophilic powders (such as cocoa powder), controls dust, and helps complete dispersion in water. Lecithin keeps cocoa and cocoa butter in a candy bar from separating. It can be used as a component of cooking sprays to prevent sticking and as a releasing agent.

Lecithin is approved by the United States Food and Drug Administration for human consumption with the status "generally recognized as safe". Lecithin is admitted by the EU as a food additive, designated as E322.

Dietary supplement

Because it contains phosphatidylcholines, lecithin is a source of choline, an essential nutrient. Clinical studies have shown benefit in acne, in improving liver function, and in lowering cholesterol, but older clinical studies in dementia and dyskinesias had found no benefit.

An earlier study using a small sample (20 men divided in 3 groups) did not detect statistically significant short term (2–4 weeks) effects on cholesterol in hyperlipidemic men.

La Leche League recommends its use to prevent blocked or plugged milk ducts which can lead to mastitis in breastfeeding women.

Egg-derived lecithin is not usually a concern for those allergic to eggs since commercially available egg lecithin is highly purified and devoid of allergy-causing egg proteins.Similarly, soy lecithin does not contain enough allergenic proteins for most people allergic to soy, although the US FDA only exempts a few soy lecithin products from its mandatory allergenic source labeling requirements.

Religious restrictions

Soy-derived lecithin is considered by some to be kitniyot and prohibited on Passover for Ashkenazi Jews when many grain-based foods are forbidden, but not at other times. This does not necessarily affect Sephardi Jews, who do not have the same restrictions on rice and kitniyot during Passover.

Muslims are not forbidden to eat lecithin per se; however, since it may be derived from animal as well as plant sources, care must be taken to ensure this source is halal. Lecithin derived from plants and egg yolks is permissible, as is that derived from animals slaughtered according to the rules of dhabihah.

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