Gluten-free foods appeal to an increasing number of consumers trying to reduce or eliminate gluten, the protein found in all forms of wheat (including durum, semolina and spelt), rye, oats, barley and related grain hybrids such as triticale and kamut. For consumers with gluten intolerance, elimination of all ingested gluten is not necessary. But for the growing number of consumers suffering from celiac disease, a lifelong autoimmune intestinal disorder, gluten must be completely removed from the diet.
Healthful and palatable
Food designers are busy getting the gluten out of formulations, but creating healthful and palatable alternatives can be challenging to overcome in baked goods, where wheat flour has historically been the base grain of choice.
Removing gluten from flour reduces its elasticity, as gluten combines with water to produce an elastic and porous web that traps gas bubbles released by action of a leavening agent. This is highly desirable in yeast-leavened products such as breads and pizza crust. Gluten is less desirable, but still necessary in small amounts, in chemically leavened products such as cakes, cookies, muffins and pie crust.
Regardless of the application, removed gluten must be replaced with other ingredients that provide similar structure.
Starchy options
Because the baking qualities of gluten-free flour are different from wheat flour, there is no single direct replacement for wheat flour. A combination of flours with varying textures, along with one or more hydrocolloids, is often used.
“The greatest challenge of formulating gluten-free bakery products is providing the structure and texture of typical baked goods,” says Kate Gilbert, associate research scientist, Grain Processing Corporation (GPC), Muscatine, IA. “Many wheat-flour alternatives can leave the finished bakery items dry, crumbly, gritty and off-flavored.”
Common gluten-free flours are derived from brown rice, buckwheat, chickpeas, corn, millet, potato, red beans, rice, sorghum, soy and tapioca. Flours considered “powdery” include buckwheat, chickpea, potato and tapioca. So-called “gritty” flours come from brown rice, corn, millet, red beans, rice, soy and sorghum.
“One of the biggest challenges I faced when making my first gluten-free cookie mix was creating a cookie that wasn’t gritty,” says Deborah Sievers, president, Doodles Cookies, LLC, Aurora, IL. “I had to find the right combination and ratio of ingredients. We use a combination of brown rice flour, tapioca, corn starch and xanthan gum to provide the proper texture and density that we desired in our cookies.”
Corn starch, potato starch and rice starch are powdery and can contribute to a smooth texture. Xanthan gum is the most-common hydrocolloid in gluten-free baked goods, as it helps gluten-free flours bind, providing some of the stretch factor of gluten. Available commercially as a powder, xanthan gum should be combined with the gluten-free flour combination before any liquid is added to make the dough or batter. Plant-derived guar gum is also useful, as it functions as a thickening and bulking agent.
“We offer a cost-effective natural gum blend of xanthan and guar that can replace gluten functionality in baked goods,” says Aida Prenzno, laboratory director, Gum Technology Corporation, Tucson, AZ. “Further, the gums work together synergistically to bind moisture, which reduces staling. The gum blend also improves cell structure, increases dough pliability and improves freeze/thaw stability.
“Usage level in gluten-free, chemically leavened products such as cookies and cakes is 0.25% to 0.50%,” says Prenzno. “Usage increases with yeast-leavened baked goods. Pizza crust requires 0.60% to 0.75%, while bread is even higher at 0.75% to 1.20%. Because the gum blend is used at such low levels, it does not influence the flavor profile of the finished product.”
A line of drop-in flour-blend replacements was tested in gluten-free cookie, muffin and cake formulations by National Starch Food Innovation, Bridgewater, NJ. Sensory panel data show the recipes come very close to similar gluten-containing commercial products on attributes such as smooth, moist and chewy. “In our tests, the cookies and muffins have exhibited outstanding shelf life, especially when compared to today’s gluten-free products,” says Yadunandan Dar, material scientist, National Starch Food Innovation.