Xanthan gum is a food additive that is primarily used to thicken, emulsify, and stabilize water-based foods. It helps things like salad dressings stay mixed, for instance. As a general rule, oil will try to pull away from other ingredients, particularly water, and the gum helps prevent this from happening. The additive also helps lend a smoother, creamier texture to certain foods, particularly ice cream. Fresh ice cream often has a really custard-like smooth taste, but this can be hard to maintain after a lot of time in a deep freeze; the gum can help preserve a lot of the smoothness and can help the ingredients resist becoming crumbly or dry. The additive is also effective as a general binding agent, and is often a really popular choice for gluten-free foods like breads that might be prone to disintegrating without the stickiness of gluten molecules to hold them together. Most food safety organizations and oversight committees have found the additive to be safe, particularly if used only in small quantities. There are some people who are allergic to it, though, and in rare cases there have been some adverse reactions.
As an Emulsifier
One of the gum’s most common uses is as an emulsifier, which basically means that it helps keep liquids from separating and pulling apart. In salad dressings, sauces, and condiments, for instance, it helps decrease the separation of oils, keeping the product well mixed while in the jar or bottle. As a result, all of the ingredients are held in a sort of suspension, and the customer doesn’t have to re-blend or shake things before use.
As a Thickening and Smoothing Agent
The same qualities that make xanthan gum a good emulsifier also make it a good thickener, of liquids and solids both. When something like salad dressing is shaken or agitated, it tends to thin out, making it easier to pour. This process is called pseudoplasticity. After the product has been poured and is allowed to rest, the gum helps it begins to thicken again slightly. Among other things, this helps it adhere to the food on which it’s been poured.
In frozen foods, xanthan gum creates the palatable feel of the food to the mouth. Along with guar gum and locust bean gum, it helps create the smooth texture of ice creams. It is also used to replace the fatty texture of egg yolks in many egg substitutes.
Improving Dough Cohesion
The additive is frequently also used as an addition to gluten-free flour, and can improve the overall quality of baked goods that are used with it. Gluten is a molecule most commonly found in wheat, and it is by nature a strong binding agent — it’s what gives most breads and baked goods their springy, chewy texture. Omitting gluten, which is all but essential for people who are allergic to wheat or prefer gluten-free products for dietary reasons, can leave many baked goods tasting dry and cooking poorly. Adding the gum to make up for the lost gluten can make a big difference.
How It’s Made
From a chemical perspective, the gum is a polysaccharide gum, or three-chain sugar compound, and it is created through the fermentation of the bacteria Xanthomonas campestris with glucose and, in some cases, sucrose, both of which are naturally occurring sugars. It is also sometimes called corn sugar, particularly on ingredient labels. This additive is very stable at a wide variety of temperatures and pH levels.
It was discovered by chemist Allene Rosalind Jeanes at the United States Department of Agriculture, and was first approved for use in foods in 1968 after going through rigorous testing for toxicity. In the United States, Canada, Europe, and many other countries, it is considered to be safe for human consumption, and it is permitted as an “approved” additive in a range of different foods. It is very effective in small quantities and usually makes up only 0.5% to 1% of the total ingredients in any given product.
Safety Concerns
Xanthan gum is a natural carbohydrate that is not absorbed into the body, so it often raises less controversy than other more chemically-based food additives. Many people still want to avoid this and other additives as a way of returning to natural foods or looking for more nature-based alternatives, though. Some people with food allergies may also be sensitive to the product, and in rare cases it has been linked to headaches, stomach pain, and diarrhea. Other "gums," such as guar gum, carrageenan, and locust bean gum, can often be substituted, though these usually come with their own sets of pros and cons.