Unlocking the versatility of soy lecithin: insights into its applications in food, pharmaceuticals, and cosmetics

What is soy lecithin?

Lecithin is a naturally occurring fatty substance that is found in various living organisms, with egg yolks and soybeans being some of the richest dietary sources. It is one of the most versatile byproducts of the oilseed industry and an important ingredient in the food, cosmetics, and pharmaceutical industry serving both as an emulsifier and stabilizer.

Soy lecithin is classified as a phospholipid, which is a type of lipid molecule. Phospholipids are a group of polar lipids that consist of two fatty acids, a glycerol unit, and a phosphate group. They are major components of cell membranes, and exist in all living organisms, playing a crucial role in maintaining the structure and function of cells [1].

The production process of soy lecithin includes several key stages: crude oil preparation, the hydration of gums, the separation of crude gums via centrifugation, gum drying, and optional subsequent steps like fluidization and further processing, which may involve deoiling, the introduction of additional surface-active ingredients, or chemical and enzymatic modifications [2].

Soy lecithin as an emulsifier: bridging the gap between oil and water

Soy lecithin is a natural emulsifier used in various applications, including food, to create stable mixtures of substances that would naturally separate, like oil and water.

Due to its amphiphilic nature, it can easily be adsorbed onto the surface or interface, reducing surface tension. Its hydrophilic end dissolves in water, while the hydrophobic end dissolves in oil, allowing it to hold emulsions together. Phosphatidylinositol in soy lecithin acts as a stabilizing barrier for emulsions.

Soy lecithin has proven to be a successful emulsifying agent for the creation of delivery systems for enzymes, nutraceuticals, vitamins, flavors, pesticides, and antimicrobial agents [3].

Soy lecithin in food: transforming food texture and quality

Soy lecithin can be used as an emulsifier, a wetting agent, for viscosity reduction, as a release agent, and for crystallization control in bakery, biscuits, ice-cream, cheese, dairy products, instant food, beverage, margarine, etc.

Bakers have long appreciated soy lecithin for its ability to improve the dough texture and extend the shelf life of their products, while creating a softer crumb in bread, extending the freshness of pastries, and enhancing the creaminess of ice cream.

Soy lecithin is also a key ingredient in chocolate production, helping to distribute the fat particles evenly throughout the chocolate mixture and ensuring a smooth and silky texture.

It also acts as a helping hand to vinaigrettes and sauces by preventing oil and water from separating and in order to maintain a consistent, creamy texture.

The ability to keep oils and fats from separating also makes lecithin ideal for making toffees and caramels keeping the candy free from any oily residue on the exterior and resulting in a smooth finish.

Soy lecithin: a powerful toolbox for pharmaceuticals

Soy lecithin is widely applied in a variety of pharmaceutical applications due to its versatile properties and beneficial effects. It is used as a pharmaceutical excipient and functional ingredient in various drug formulations acting as a dispersing, emulsifying, coating, and stabilizing agent.

It is included in intramuscular and intravenous injections, parenteral nutrition formulations, and topical products such as creams and ointments.

It is also used in suppository bases, to reduce the brittleness of suppositories and improve the suppository's consistency and has been investigated for its potential to enhance the absorption of drugs in an intranasal insulin formulation.

It is commonly used as a component of enteral and parenteral nutrition formulations to provide a source of essential phospholipids, which are important for cell membrane function [4].

Soy lecithin in cosmetics: a natural touch for skin health

Soy lecithin is widely used in the cosmetics industry for its emulsifying, moisturizing, and skin-conditioning properties. Due to its amphiphilic nature, soy lecithin can effectively blend oil and water-based ingredients, resulting in stable and visually appealing formulations such as creams, lotions, and serums.

It acts as an emollient, increasing moisture levels and hydrating cracked or dry skin while stimulating collagen production to enhance skin elasticity and restore healthy skin.

Soy lecithin has antioxidant properties, and it helps the skin repair itself, leading to a brighter skin tone. It can also assist in the penetration of active ingredients enhancing the overall effectiveness of the product.

References:

1. Xie M., (2018). Phospholipids. Reference Module in Food Science. DOI:10.1016/b978-0-08-100596-5.21597-7

2. List G.R., (2015). Soybean Lecithin: Food, Industrial Uses, and Other Applications. Polar Lipids, 1–33. DOI:10.1016/b978-1-63067-044-3.50005-4

3. Deng L., (2021). Current Progress in the Utilization of Soy-Based Emulsifiers in Food Applications—A Review. Foods, 10(6), 1354. DOI:10.3390/foods10061354

4. https://file.wuxuwang.com/hpe/HPE6/HPE6_169.pdf