We previously discussed the importance of starches in gluten-free baking. Although starch-heavy flours are the least nutritious of the gluten-free flours on the market, starch is critical to providing the texture necessary for many gluten-free foods.
Gluten-free home bakers are familiar with starches such as corn, arrowroot, potato and tapioca starches. But what does it mean when your favorite packaged product lists the vague mystery ingredient “modified food starch?”
Celiacs rightly tend to avoid any ingredient that is ambiguous in its gluten-free status. As with the gluten-free status of alcohol, rumors abound in the gluten-free world as to the gluten-free status of modified food starch. Let’s take a look at what this ingredient really is.
Any starch, including the gluten-free starches we mentioned above, can be chemically modified in a variety of ways to change how they function in recipes.
Are Foods with Modified Food Starch Gluten-Free?
Starch modifications can improve a food’s ability to withstand cooling, heating, freezing and defrosting. Modifying a starch by pre-gelatinizing it is how instant puddings can become thickened with only the addition of cold milk, without cooking it. Acid-treating or oxidizing certain starches can change the starch molecule to lower its viscosity. Roasting some starches along with the addition of hydrochloric acid produces dextrin, which can increase crispness of commercially-produced foods. These are just a few of the many modifications that can be made to food starches to change them molecularly.
Although any food starch can be modified, in the United States all modified food starches are gluten-free unless made from wheat. Barley and rye starches are not commonly used. Because of recent food allergen labeling requirements, in the United States any product that uses wheat starch as the basis of its “modified food starch” must list the ingredient as “modified wheat starch” or some similar wording that specifies the product’s wheat-based origin. Alternately, you may find the mention of wheat in the package’s allergen warning. If the product simply says “modified food starch” and has no wheat allergen warning, it is derived from a gluten-free source. The most common sources include corn, potato and tapioca.
Can Wheat Starch Be Considered Gluten-Free?
In Europe, however, wheat starch is often considered gluten-free! Procedures for isolating the starch part of the wheat grain can effectively remove nearly all traces of gluten, leaving a starch that has little enough gluten to be called “gluten-free” by European standards.
Countries have different thresholds for gluten content. The United States has not finalized an acceptable gluten content threshold for foods marked “gluten-free”, but in Europe wheat starch that has the gluten removed tests at below the acceptable 200 parts per million (ppm) of gluten and can therefore be labeled “gluten-free”.
The use of the 200 ppm threshold is highly controversial. In Australia the gluten-free standard is much lower, and many celiacs in the United States would like to see this country also adopt a law that requires the gluten-free label to only be used on products well below the 200 ppm. There is evidence that many celiacs react to gluten levels that are lower than 200 ppm.
Until a wheat starch exists that can test reliably at a much lower level of gluten than 200 ppm (perhaps under 20 ppm, the most widely cited proposed standard) most experts suggest avoiding wheat starch. Instead, stick to using gluten-free starches in your own baking and choosing only processed foods that contain modified food starch that isn’t derived from wheat.