Lecithin: Nature's Versatile Volatile Emulsifier

Lecithin was first isolated as an orange-colored substance in egg yolk. An important characteristic of this material was that it contained phosphorus, organically bound to a lipid-type structure. Industrial production of lecithin began when the Bollman extraction process enabled large quantities to be obtained from soybeans instead of eggs.

It took scientists a number of years to discover that the isolated chemicals werent uniformly structured, but were instead a group of chemically similar, but clearly differentiated, components that are now classified as phospholipids or phosphatides. Scientists also found that this class of chemicals is present in all organic tissue. All of these components can basically be called lecithin, but they may deliver entirely different functionalities in their individual applications.

The active components that all lecithins have in common are phospholipids. These consist of hydrophobic long-chain fatty acids counterbalanced with polar, hydrophilic phosphates. A concentration of phospholipids at the oil-water interface lowers the surface tension and makes emulsification possible. Once this occurs, phospholipids at the surface of the oil or water droplets form barriers to prevent the droplets from coalescing.

Industry employment

Lecithins are natures principal emulsifying agents. They greatly speed up dispersion of fatty and aqueous components in many types of food applications, including bread, biscuits, sweet pastries, convenience foods, ice cream, chocolate and margarine.

Confectionery. The most widely known and firmly established application for lecithin is in the making of confections, and chewing- and bubble-gum products. This natural ingredient improves the quality and eating properties of confectionery items and is used for both functional and process-technology purposes. Lecithin has a positive effect on form stability, allowing the addition of increased amounts of glucose syrup for shelf-life extension in chewing and bubble gum. It aids the binding of water in the chewing-gum mass, prolongs flavor release, extends shelf life, improves chewability, releases flavor and produces a fresher gum with enhanced smoothness.

In chocolate manufacture, such as chocolate bars and coatings, it reduces the amount of cocoa butter required, reduces viscosity and yield value of chocolate, improves flow properties, improves shelf life by reducing fat-bloom formation, and prevents sugar recrystallization.

Margarines. Lecithin also is commonly used as an emulsifier in the manufacture of frying, bakery, and diet margarine and spreads. Due to the bipolar structure of lecithin molecules, it helps reduce the surface tension between the oil and water phases. As a result, a homogeneous and fine distribution of droplet size can be obtained in spreads.

Bakery. In bakery products, emulsifiers can help reduce the rate of starch retrogradationthe process under which the starch molecules revert back to their original state as rigid crystalline granulesmaking the product stale. Emulsifiers also can work with lipoproteins to stabilize dough by forming gluten networks. In biscuits, crackers, pies and cakes, a 1% to 3% concentration of lecithin promotes fat distribution and shortening action, facilitates mixing, and acts as an internal release agent, which prevents the mixture from sticking to the pan, a major benefit for shape control.

Lecithins also accelerate moisture distribution, making mixing easier and improving texture. They assist in producing a uniform crust color in pies and reduce surface marking or cracking, since the fat is more evenly distributed.

One of the main benefits of lecithin, particularly in bakery goods, is ensuring handling ease and stability during manufacturing. Powdered lecithin formulations are designed primarily to assist with product flow, density and handling during different production processes. Additional benefits include shelf-life extension, texture improvement, production optimization and cost reduction.

Instant foods. In powdered instant foods, emulsifiers improve the wettability and dispersibility of powders, as they help to prevent powder particles from sticking together and becoming lumpy during rehydration.

Forms for every application

Lecithins are available in four forms: fluid, for cake and confectionery toppings; tailored fluid, for bakery; deoiled, for chocolate, confectionery and salad dressings; and selected and/or fractionated deoiled forms for instant powder beverages.

Recent developments in the selection of different raw materials used as carriers for lecithin can suit different manufacturing requirements. Wheat flour, calcium sulfate, lactose and palm oil all provide different types of technical benefits to manufacturers. Enzymes, as well as hydrocolloids like xanthan gum, carrageenan, galactomannans and alginates, can each contribute special functionalities and synergistic effects when employed in blends as lecithin carriers.

Compared with traditional fluid lecithin, which is quite viscous and difficult to handle, powdered lecithin allows manufacturers to use it just as they would other common powdered ingredients. It also is possible to combine powdered lecithin with other fatty ingredients in powdered form, again offering additional ease of handling and functionality.

The complexity involved needs to be well monitored, especially when the fat content is quite high in the final mix, to avoid stickiness, caking, color variation and, in particular, to precisely guarantee the powder flowability.

A quality match

Because lecithin isnt a uniform, standard materialbut a natural mixture of a series of surface-active components that produce significant variation in their composition, functionality and suitability for different applicationsquality differences occur.

Some applications require extremely detailed quality requirements while, for others, that degree of sophistication would be overkill, says Cindy Palermo, marketing communications lead, Americas, Cargill Texturizing Solutions, Wayzata, MN. We developed a Lecithin Quality Toolbox to help food manufacturers pinpoint their needs much more precisely to arrive at a clear and cost-effective product/application match.

Requirements can vary from color or transparency specifications to more complex requirements, such as low-iron lecithin for margarine products and specific phospholipids patterns in chocolate or dietary applications. Microbial requirements also can vary considerably depending on the application, with infant nutrition being a particularly sensitive area. Food product recalls and contamination incidents are increasing concerns in risk management and crisis prevention. This applies particularly to processes involving lecithins.

Jerôme Clément is bakery applications specialist, Cargill Texturizing Solutions, Baupte, France. Cargill Texturizing Solutions (cargilltexturizing.com) is one of the worlds leading suppliers of texturizers and emulsifiers to the global food and beverage industry. From design through development to manufacturing, it is committed to creating with its customers innovative new products for consumers to enjoy. Cargill (cargill.com) is an international provider of food, agricultural and risk management products and services, with 158,000 employees in 66 countries.