Emulsifiers: Mending the Differences in Our Foods

After moving to Washington, D.C., I quickly learned that a favorite weekend pastime of Washingtonians is brunch. While I’d like to consider myself an adventurous person, nine times out of 10 I order the same dish wherever I go. Eggs Benedict is a staple when it comes to brunch, and what makes or breaks the plate is the one and only Hollandaise sauce. This personal favorite is a combination of egg yolk, butter, water and lemon juice or vinegar, making for the ultimate emulsion.

Have you ever thought about emulsions in food?  I realize not everyone is a food scientist, but here are a few interesting things you should know about emulsifiers in food.

What Are Emulsifiers?

Emulsifiers are found in many food products we buy at the grocery store. Beverages, milk, ice cream and dressings often have these additives to keep the products stable. What do we mean by that? Have you ever tried mixing together oil and water for a simple salad dressing? For a short time, the two may appear homogenously mixed, but after a few minutes they are completely separated. Emulsifiers keep two components that normally do not mix well together from separating. Because oil and water are so chemically different, they can often be challenging to mix together. If we want to overcome this, we add the emulsifier. Said in a different way, if water and oil were a fighting couple, an emulsifier would be the therapist that mends their relationship. Emulsifiers are combined with the two unmixable components through stirring and sometimes heat.

What Kind of Foods Are They In?

Emulsifiers can either be naturally present or added as ingredients. In the case of the highly stable emulsion of mayonnaise, an egg yolk protein called lecithin aids in stabilizing the oil, egg and lemon juice mixture. This is an example of a naturally present emulsion. However, to keep ranch dressing well mixed, soy lecithin (same protein, difference source) may have been added during manufacturing to accomplish the exact same objective.

Ice cream is perhaps one of the most beautifully complex emulsions out there. In case you aren’t an expert on my favorite product, ice cream is a homogenous mixture of air, sugar, fat globules, and ice crystals. Without the fine distribution of air, ice cream would be a solid block. If the fat globules were not distributed, it wouldn’t melt in your mouth (a common issue with no fat ice creams). And we all know what horrors occur when ice cream is freezer-burnt, caused by the conglomeration of ice crystals. It is absolutely essential for ice cream to be properly mixed, and emulsifiers guarantee a great end product.

Another example is milk, which is an emulsion of protein solids, butterfat and water. The emulsifier here is in the milk fat. The effect of adding an acid (such as lemon juice) to milk makes it curdle. Similarly, a hot dog’s filling is an emulsion of fat, water and meat.

Do We Need Emulsifiers?

Sometimes emulsifiers are used simply to improve the quality of foods. This is the case for salad dressings. Other times they are essential to have a tasty product, as is the case with ice cream. This is also true with gluten-free baked goods because these products often have difficulty standing up to their gluten-rich counterparts. When we improve the quality of foods, we in turn can extend shelf life, an effective means of reducing food waste.

Are They Safe?

Yes. The U.S. Food and Drug Administration (FDA) confirms the safe use of the emulsifiers used in food and beverages.  They must pass a rigorous evaluation in order to receive a "generally recognized as safe" (GRAS) certification by the FDA.

How Are Emulsifiers Listed on a Food Label?

Let’s look at the ones you’ll most likely see on the ingredient label of your favorite foods. Lecithin is found in egg yolks and acts as the emulsifier in sauces and mayonnaise. Lecithin also can be found in soy and can be used in products like chocolate and baked goods. Other common emulsifiers include sodium stearoyl lactylate, mono- and di-glycerols, ammonium phosphatide, locust bean gum, and xanthan gum.

Go forth and enjoy emulsions! Now you have a new understanding of a well-mixed vinaigrette dressing for your salad and can appreciate the smoothness of an ice cream as it melts in your mouth.

This blog post was written by Jacob Farr and Edward Orzechowski, food technology research intern from Catholic University.

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