Xanthan (ZAN than) gum and guar (gwar) gum are the most frequently used gums in gluten-free recipes and gluten-free products.
Gums are "hydrocolloidals." They attract water, bind, thicken and emulsify gluten-free ingredients. If you don't add gum to most gluten-free baked goods, especially breads, you are apt to end up with a crumbly dry disappointment.
But if you aren't completely satisfied with the texture of your homemade gluten-free breads, whether you use xanthan gum OR guar gum, consider using a combination of both xanthan gum and guar gum in your recipes.
Food chemists have learned that gums used in food preparation have very unique properties and when combined can improve the texture and mouth feel of gluten-free baked goods. This is called a "synergistic effect" which means that the properties of one gum enhance the properties of the other.
Xanthan gum is manufactured through a fermentation process. A bacteria called xanthomonas campestris is used to ferment a sugar like dextrose (from corn,) glucose, lactose or sucrose. Xanthan gum is used to make liquids more viscous, or thick.
Guar gum is extracted from guar beans. Like xanthan gum, guar gum is also used as a thickener in gluten-free baked goods, but it doesn't exhibit the gelling properties of xanthan gum. Guar gum good is a good emulsifier (it helps fat molecules blend) and is high in soluble fiber.
Have you noticed how gluten-free breads made solely with xanthan gum have a tendency to feel and taste slightly wet even when completely cool?
Or how breads made only with guar gum fail to hold their shape during baking and tend to collapse in the middle as they bake and cool? And how they dry out more quickly?
The reason for these very different end results is because xanthan gum and guar gum each bring different functions to gluten-free recipes.
According to Swiss-based Jungbunzlauer, a manufacturer of food-grade gums, "Combinations of xanthan gum with galactomannans [like guar gum] show a synergistic viscosity increase, in comparison to pure guar gum solutions."
Next time you bake a loaf of homemade gluten-free bread substitute half of the gum called for in the recipe with its synergistic partner. If the recipe calls for 1 tablespoon of xanthan gum, use 1 1/2 teaspoons of xanthan gum and 1 1/2 teaspoons of guar gum.
You will find that your breads bake up with more spring, stay moist longer without being "wet" and don't collapse in the center during the final minutes of baking and cooling. I think you will be pleasantly surprised at the results.Xanthan Gum or Guar Gum - Share Your Gluten-Free Baking Experiences
Suggested Reading:More About Xanthan Gum from Jungbunzlauer