Hydrocolloids: An Innovative and Essential Gluten Replacer

If you have ever baked anything gluten-free, you have used hydrocolloids! Xanthan gum and psyllium husks are amongst the most used gluten replacers in commercial mixes, see King Arthur Gluten-Free Bread Flour, and Bob Red Mill 1:1 flour as examples. 

I have so many things to say about our friends the hydrocolloids. In this article, you will learn: their chemical makeup, their role, where they come from and how to choose the right hydrocolloid.

Chemical Makeup

Hydrocolloids are polysaccharides--long long long chains of sugar (glucose). Glucose is an interesting molecule because it contains 5 hydroxyl groups, which are highly polar areas that can hydrogen-bond with adjacent water molecules. This makes our hydrocolloid friends (like all sugars), very water soluble.

Hydrocolloids are also BIG molecules, and so their high molecular weight contributes to the strength of the intermolecular forces. In other words, hydrocolloids love water. When mixed in water, they dissolve in a coiled manner that forms a gelatinous dispersion: cross linking of their long polymer chains happen, which forms a three-dimensional cohesive network. Remember, this is exactly what gluten does when gliadin-glutenin align together during kneading.

Role

As hinted above, their most important role is to function as a gluten replacer by providing a structural viscoelastic network to baked goods. However, gluten-free baked goods manufacturers add them to their formulations for other important reasons.

• Nutrition: gluten-free formulations have been criticized for lack of nutritional value, and adding hydrocolloids provide a wholesome dose of dietary fiber.
• Product longevity: water activity measures the amount of water in a baked good that is available for bacterial growth. Because hydrocolloids readily form hydrogen bonds with water, it decreases the amount of water that is available to fuel the biological processes of bacteria.
• Texture: hydrocolloids improve the texture of gluten-free baked goods, and for us as bakers, make our dough/batter easier to handle.

Hydrocolloid Origin

Hydrocolloids have varied origins. They can come from plant tissue like pectin, or viscous plants like psyllium, or fermentation like xanthan. While some hydrocolloids are likely things we don't see very often, some like gelatine should be quite familiar. Here is a table showing the main hydrocolloids used in the food industry, and their origin. This table comes from a peer-reviewed article located here.

Choosing the Right Hydrocolloid

As you can see, there is an overwhelming amount of hydrocolloids to choose from, and as you probably guessed it, they aren't quite interchangeable. Some form a gel at room temperature, some activate when heat is applied, some are more suited for baking and others for products like creams and custards. 

Unfortunately, even peer-reviewed articles seem to yield conflicting answers when it comes to choosing the right hydrocolloid as a gluten replacer. For example, this paper shows that hydroxypropyl methylcellulose outperformed all other options in bread baking, while this paper shows it had antagonistic effects on bread volume. It's fascinating, and obviously several variables are at work here, including the flours used and baking environment. However, it's not super helpful in our kitchens when the scientists don't agree!

Furthermore, some of these products may or may not be readily available where you live. Or you may have sensitivities to some of the hydrocolloids--xanthan gum being a popular gluten replacer that may cause irritation in some. Or if you are running a cottage food business like me, you are restricted by your health department in which hydrocolloid you can use!

So what I have done here is list the hydrocolloids I use and where/how I use them, because there is no way for me to experiment with all of them--and the literature is not yet super helpful!

For Batter-Based Bakes (Cupcakes, Muffins, Cakes)

I love the mix and synergy between xanthan gum/pectin, just like in Better Batter. That would be a 5% hydrocolloid formulation by weight of flour mix: 3% xanthan and 2% pectin. Have a sensitivity to xanthan gum and/or corn? You could try: 6% guar gum and 2% pectin for a total of 8% hydrocolloid. You can see here my DIY all-purpose mix.

For Pastries/Pies

I like 2% xanthan gum WITH the addition of flavor/texture enhancer like milk powder AND flours with a high amylose content to contribute to the crispiness of the final product. Check out my Ultimate Flour Guide to find those flours, and you can also look at my cottage bakery's DIY pastry mix.

For Breads

This is where it gets tricky. My absolute preference is psyllium husk, which I can't use in my business due to California cottage food laws. The reason psyllium is a great gluten replacer is because it forms a gel at room temperature, and therefore improves dough handling. It gives us the possibility to go beyond batter-breads and do some cool shaping! You could replace it with ⅓ of konjac, which I also can't use per my health department. And that leaves me an interesting mix of hydrocolloids. So here is a summary of my recommendations for your bread hydrocolloid:

• Whole Psyllium: 4.5% of flour by mass
• Psyllium Powder: 3.5% of flour by mass
• Konjac Powder: 1.5% of flour by mass
• My Business Mix: 1% HPMC, 1.5% pectin and 2% xanthan gum of flour by mass

For example, if you have 100 grams of flour, you could use 4.5 grams of whole psyllium, or 3.5 grams of psyllium powder, and so on. Please note that psyllium absorbs ten times its weight in water, which results in breads with at least 115% hydration!

Curiously, I found that HPMC works antagonistically with high protein flours, and somewhat "reigns in" and brings the crust closer together from the really high rise pectin/xanthan gives! See below, HPMC only on the left and pectin/xanthan on the right. Same bread recipe otherwise!

Well, that concludes my hydrocolloid article! If you end up testing hydrocolloids I have not tested yet, please let me know!