Emulsifiers - Friend or Foe?

Food bloggers usually attack ingredients they cannot pronounce so let's dig into a common class of food ingredient with uncommon names, emulsifiers.

What are emulsifiers? why are they found in so many foods? Well, let's start with what is an emulsion first. An emulsion is basically a mixture of two or more immiscible liquids such as an oil suspended in water or a water suspended in oil. You have all heard "Oil and water don't mix". Yes, true until you introduce an emulsifier under the right processing conditions. Most of the foods you consume are emulsions stabilized by the skill of food scientists using the right ingredients and the right process to create stable oil in water or water in oil emulsion systems. Some emulsions can be quite easy to form, but most are quite unstable!

Emulsifiers are in most processed foods, and not just in the obvious formulations such as dressings, shortenings or mayonnaise. This is because in addition to emulsifying they also help with bunch of other things like texture, aeration, bread cell structure, shelf-life, fat reduction, and more.

Emulsifiers are food additives approved by each country's governing regulatory bodies. They have portions that love being in fats (lipophilic), and portions that love being in water (hydrophilic). They form a layer at the interfacial boundary of oil and water. An emulsifier reduces the interfacial tension between the two immiscible liquids, and prevents droplets from coalescing. This boundary layer protects the oil droplet dispersed in water or in the case of an water in oil emulsion they would protect the water droplet that is dispersed in oil.

Image 1. Oil in water and water in oil emulsions

Making an emulsion is not simply adding oil, water, and an emulsifier together. There is a need to put some energy into the system in the form of a mixing operation. This process can be quite simple as just a little mixing or it can require more complex processes using high pressure homogenizers, and multiple steps depending on your ingredients, and the criteria needed for the finished good. Homogenization helps us reduce the droplet size which are coated by the emulsifier. Typically, the smaller the particle size the more stable the emulsion. However, there is a minimum achievable droplet size. Generally speaking, smaller emulsifiers can achieve smaller droplet sizes vs. larger size emulsifiers. Some emulsions call for multilayers to be built around the droplets of interest. Some foods are emulsified, and transformed into liquid end products to consumer while some emulsions are formed, and then spray dried into powders that are then used as ingredients in foods. As mentioned, there are very few things you consume that are not emulsions!

What is this HLB value I keep hearing about?

The hydrophilic-lipophilic balance (HLB) value of an emulsifier enables food scientist to narrow down their emulsifier selections. HLB value is simply a measure of how water soluble or fat soluble an emulsifier is. The higher it is, the more hydrophilic an emulsifier is. A value of 10 will indicate an emulsifier that is attracted to water and oil in similar affinity. As mentioned above, HLB value helps us narrow down our emulsifier process. Unfortunately, HLB value alone is not enough to pick the right emulsifier. We need to consider the functionality we are looking for, interactions in our matrix and much more to make the suitable selection.

With time pretty much all emulsions will break! We all know from laws of thermodynamics that entropy increases over time, things tend to move towards disorder. Just like everything else in the universe, emulsion systems will eventually break. Our unappreciated emulsifiers are always hard at work trying to establish some level of order in our foods so that they perform the way we want it to perform. For example: naturally, oil is supposed to separate from a naturally made hazelnut spread, but we don't like how that separated oil looks like sitting at the top of the jar so we treat it as it has gone bad rather than just mixing it a spoon. So, we add an emulsifier to ensure the fat stays nicely dispersed. You can find "natural" dressings in stores that require you to give a little extra shake prior to usage. That is because a very capable synthetic emulsifier has been kept out of it.

Simply put, emulsifiers are in our food because they are ensuring packaged foods keep managing our expectations of consistency, texture, smoothness, flavor and shelf-life.

What about Natural vs. Synthetic?

There are many emulsifiers to choose from. They can be naturally occurring emulsifiers, and man made emulsifiers.

Some of the natural emulsifiers are:

- Lecithin is probably the most commonly used emulsifier in the US. It is a mixture of phospholipids and just like the phospholipids in our cells lecithin can make a membrane layer around lipids and help with emulsification. It comes in powder and liquid forms, and in different carriers. It is found in many baked goods, beverages, ice-cream, chocolate, and more. There are many different lecithin to choose from with varying emulsifying capabilities. You can choose ones that are either more hydrophobic or lipophilic based on the type of emulsion you need. Lecithin, being a natural emulsifier, has additional benefits such as lowering blood pressure, support cell membrane, healthy brain function, and helping with lowering cholesterol.

- Milk proteins such as casein, and whey protein are typically added to a system for nutritional purposes, but it can also perform as an emulsifier. In addition to the emulsifying abilities it can also help with texture, and flavor. Make sure you understand the other ingredients in your system and their interactions because some proteins can coagulate in the presence of some salts, and cause you all kinds of problems!

- Gum Arabic is a great natural emulsifier. Sourced from the Acacia tree. It helps with stabilizing emulsions in baked goods, beverages, ice-cream, fillings, and confectionary applications. Remember that it is a gum so it will also thicken, and impact the texture of your system.

There are many synthetic emulsifiers, here are some of the leading ones:

- Mono-di glycerides - After lecithin probably the second most used emulsifier. Made from vegetable oils and glycerin. Yes, we make them synthetically, but our bodies also make mono/di glycerides from triglycerides so the material is not a complete alien substance to us. Used in many baked goods, margarines, shortenings. It is great for dispersing the fat, and helping with the stability of the emulsion.

- Lactic acid esters of mono/di glycerides (LACTEM) is used mostly for fillings and icings. LACTEM mostly helps with aeration and stabilizing the foam when needed.

- Diacetyl tartaric acid ester of mono/di glycerides (DATEM), damn what a name for the common consumer. From what I have seen over the years, it does a good job with helping strengthening the dough, enabling a softer crumb in breads, and other baked goods.

- Sodium stearoyl lactate (SSL), another scary name for the consumer to see, but it does wonders in breads by helping with cell structure, dough strengthening, crumb softening. It is also a good fat reducer.

- Propylene glycol monoesters (PGME) is another common emulsifier that also helps with saturated fat reduction in formulas. Propylene glycol (PG) is used in numerous foods as an emulsifier. Sometimes it gets confused with ethylene glycol which is highly toxic. You can see it in a lot of foods such as confectionary, baked goods, and frozen goods. It is also used to make a lot of color and flavor additives. So sometimes emulsifiers might not make it onto the label, but they do make it into the product via colors, and flavors that are used in the formulation...and never forget there are very few products that do not have colors and/or flavors added to them.

- Polysorbates are common just like PG and just like PG can find it's way into your foods through inclusions, and ingredients.

All these synthetic emulsifiers come with E numbers making it challenging to use in regions where your customers require E number free products.

Natural emulsifiers are typically quite safe and some actually beneficial for you. Synthetics are much better regulated these days. Preference of synthetics comes from them being cheaper, requiring smaller amounts in your formula, and sometimes from the complexity of what we ask from the emulsifier. Should you avoid some emulsifiers? Yes, partially hydrogenated oils for example. If interested in how to "clean up" your label contact us.

A lot can go into when selecting emulsifiers such as regulatory, labeling criteria, cost, functionality, the processing capabilities you have at your disposal, storage, and more.

Remember, we cannot attack all emulsifiers by saying they are not natural when the very purpose of their existence is to change the natural "disordered state" of a system the unnatural "ordered state". Another example of why the food industry needs to do a better job in educating the customers on the ingredients we provide rather than the customers reading something on the web.