Emulsified food is becoming increasingly common. Processed and packaged foods are the main sources of emulsifiers. This article looks into the different emulsifiers commonly used in food and skin care products.
What Are Emulsifiers?
An emulsion is a mixture of two or more liquids that are usually not mixable but mix under specific circumstances — generally by using substances that help them mix. These substances are called emulsifiers. In an emulsion, one liquid is dispersed in the other.
As water and oil don’t usually mix, emulsifiers help mix them. Emulsifiers are traditionally prepared from plant and animal sources, but many synthetic emulsifiers exist. Emulsifiers are added to processed foods like mayonnaise, ice cream, chocolates, peanut butter, cookies, creamy sauces, margarine, and baked goods to prevent the separation of their oil and water components. Emulsifiers also give these foods a smooth texture and increase their shelf life.
The Food and Drug Administration (FDA) approves the emulsifiers used in foods in the U.S. Hydrocolloids are currently the most widely used emulsifiers made from natural sources. They’re also known as gums because of the texture of the foods containing hydrocolloids. Hydrocolloids can be modified to support the texture of the specific food product, increase its shelf life, and add flavor. Using emulsifiers in food products makes them less sticky and easier to eat.
Hydrocolloids are usually made from multiple sources. Plants, including locust bean gum, carrageenan, pectin, and starch, are the most common sources of emulsifiers. Animal sources include crustacean shells and microorganisms. Many synthetic emulsifiers may have some harmful health effects.
In addition to food products, pharmaceutical, personal hygiene, and cosmetic products also contain emulsifiers. Creams, ointments, balms, pastes, and films contain emulsifiers to blend water-based and oil-based ingredients. Medicines use emulsions to enclose their active ingredient to prolong its shelf life and prevent interaction with other chemicals before its intended use. This helps safeguard the effectiveness of the specific dosage and makes the medicine easily enter the digestive system.
How Do Emulsifiers Work?
An emulsion contains two phases — a dispersed phase and a continuous phase. The continuous phase in the emulsion typically holds the dispersed phase. In an oil-in-water emulsion, water is the continuous phase, and oil is the dispersed phase. In a water-in-oil emulsion, the continuous phase is oil. Emulsifiers make both types of emulsions.
Milk is the perfect example of a natural oil-in-water emulsion. The oil in the milk is suspended as tiny droplets in the aqueous (water) phase. On the other hand, margarine is a water-in-oil emulsion, where drops of water are held within the margarine fat.
The ends of the emulsifiers vary in their constitution. One end is hydrophilic (water-loving), and the other is hydrophobic (oil-loving). This specific quality helps emulsifiers build a physical boundary to prevent oil and water droplets from mixing while dispersing them within each other to create a stable and homogeneous mixture called an emulsion.
When you add emulsifiers to an oil-in-water emulsion, they envelop the oil droplet with their hydrophobic ends, while their hydrophilic ends point in the other direction and are attracted to the water molecules. In a water-in-oil emulsion, the emulsifier orientation is reversed.
What Are the Different Types of Emulsifiers?
Several processed and packaged foods contain emulsifiers. Some of the most common emulsifiers in food products include soy lecithin, carrageenan, mono- and diglycerides, carboxymethylcellulose, and polysorbate. Emulsifiers in skin care products include sodium lauryl sulfate (SLS), benzalkonium chloride, cetearyl alcohol, stearic acid, glyceryl stearate, and ceteareth-20.
Lecithins are made of phospholipids extracted from soybeans and egg yolk. They’re common in salad dressings, baked products, and chocolates. The concentration of the emulsifier depends on the preparation. Fatty acids extracted from vegetable oils are another popular source of emulsifiers. Sometimes, animal fats may serve as an alternative to vegetable oils. Ice creams and cakes typically contain emulsifiers extracted from fatty acids. Bread and margarine use synthetic emulsifiers sourced from glycerol.
