That Takes the Cake: Gluten-Free Baking Gets a Boost from Walnut Meal

With all the buzz surrounding gluten-free eating these days, I have been working with the California Walnut Board to come up with new ways to use walnuts.

With all the buzz surrounding gluten-free eating these days, I have been working with the California Walnut Board to come up with new ways to use walnuts—naturally gluten-free from the beginning—in products that suit the gluten-free lifestyle. That's why I was so surprised to hear a well-known industry watcher comment that gluten-free is "sooo last summer."

Really? I wonder how many of the roughly 1 in 133 Americans diagnosed with celiac disease—as noted on http://www.celiaccentral.org/Celiac-Disease/Facts-Figures/35/—would agree. For them, going gluten-free isn't just a diet trend; it's a way of life. That's because celiac disease is a genetic condition that renders its sufferers unable to tolerate the gluten proteins in wheat, barley, and rye.

This is not the same as a wheat allergy. Rather, when a celiac person consumes anything containing gluten, their immune system goes into overdrive, damaging the lining of the small intestine in such a way that makes it harder to absorb nutrients. Over time, this leads to a sort of slow, low-grade malnutrition that persists regardless of how much the celiac patient eats.

Seen in that light, the development of gluten-free foods looks less like just a clever marketing strategy—and one with as many as 2 million beneficiaries, besides. Maybe that's why supermarket aisles have arisen to stock foods targeting the gluten-free consumer. The abundance of those foods, however, belies the veritable marathon of R&D legwork necessary to bring about their creation. Why? Because gluten, it turns out, is one handy protein.

The Good, the Bad, and the Gluten
Particularly in the bakery realm, the gluten proteins in wheat, barley, and rye flours are exquisitely suited to providing structure and function. For example, these proteins crosslink to form an elastic network that stretches to capture leavening gases in bread dough as it rises. In bagels, vigorous kneading develops strength and cohesion in the network to give the bagels their chew. Even pancakes and pastas count on gluten simply to hold together as a unit.

Which raises the question: If gluten's so great, how do gluten-free products survive without it? With a little help from alternative ingredients. Eliminating gluten removes an important functional protein. Replacing it with similarly functional substitutes makes it possible to formulate foods that not only meet the celiac community's needs, but look, taste, and perform like the originals.

Walnuts: A Gluten Solution
We put this strategy to the test in our own kitchen, using walnut meal as the gluten-free substitute. It wasn't the first time we put walnuts to work in a gluten-free baked good, as we featured a classic European-style macaron at last year's IFT Food Expo that contained walnut meal, egg whites, sugar, and cocoa powder—nothing more, nothing less. That was such a hit that it was only natural to see what walnut meal could bring to other gluten-free baked goods this year.

We started by reformulating a walnut cake popular in the Greek isles, where walnuts have long appeared in baked goods, pastries, and sweets. The choice was strategic in that this particular cake is meant to be rich, dense, and nearly flourless—almost more of a torte than a cake. Yet while that gave us less gluten to eliminate from the start, the original formulation still contained enough gluten from the addition of breadcrumbs to require food science savvy in figuring out a gluten solution.

The trick was creating a batter with enough internal cohesion to serve as "architecture" for the cake. That's hard to do without the balance of starch and protein in traditional cake flour, but we got the ball rolling with a combination of about 15% walnut meal supplemented by just over 2.5% gluten-free pregelatinized brown-rice flour. Whereas the walnut meal contributes substance and bulk to the mix, the pregelatinized rice flour binds the water needed to tie everything together into an "official" batter.

A host of gluten-free flours and functional starches made from all-natural, label-friendly ingredients like tapioca, cassava, and quinoa can do the same work in other cakes that brown-rice flour did in ours. What's more, hydrocolloid suppliers point out the value of gums like xanthan, guar, tara, and carrageenan in binding water and improving cell structure in everything from gluten-free cakes and muffins to pizza crusts, cookies, and tortillas.

After tackling batter structure and cohesion, we took on cake volume. Again, our prototype isn't supposed to be light and airy, but it still needs lift, and we got the right amount from about 30% whipped egg white. This provided a sturdy foam that maintained volume in the batter even with the added weight of walnut pieces in an amount almost equal to that of the walnut meal itself. To keep that volume throughout production, it's always best to take care when working with delicate egg whites: Don't over-whip, fold them into the batter gently, and fill cake molds slowly to avert foam deflation.

Walnuts Bring More to the Table

So how did it all come out? Just ask visitors to the California Walnut Board's booth at IFT. Like last year's macarons, this year's cake was a hit. Our functional blend of walnut meal, rice flour, and egg protein yielded a finished cake with the structure, height, color, and crumb quality to impress not only those in the gluten-averse camp but palates that can tolerate gluten just fine,.

But walnuts and walnut meal bring so much more to the table than gluten replacement alone. For one, their unique, nutty flavor isn't just preferable to the grainy or beany notes that plague some gluten-free flours; it's an out-and-out positive addition to the cake's overall profile. And at roughly 65% fat, walnuts lend an inimitable richness that makes an already-sumptuous texture all the more decadent.

It helps that the fat found in walnuts is the kind that actually looks good on a label. Walnuts stand alone among nuts in providing a significant amount of the heart-healthy omega-3 fatty acid alpha linolenic acid (ALA)—2.5 grams per ounce . Nutrition-aware consumers recognize ALA as a fat they should be getting more of—and if they can get it in the form of a craveable gluten-free walnut cake, they'll take it and have a second helping, too.

Finally, as an all-natural, familiar food that consumers stock in their own kitchens, walnuts win with label-reading consumers over more "chemical-sounding" ingredients any day. Considering how many gluten-free shoppers seek not just to avoid gluten but to embrace a natural, "whole-foods" approach to their diets, that's an advantage any gluten-free food, baked good or otherwise, can use. You may leave consumers wondering, "Gluten? Who needs it?"

So make walnuts the hero in your next gluten-free reformulation. You can find walnut meal available for industrial production from a number of suppliers, many of whom we list in our 2010 handbook, California Walnuts for Product Developers. And do source the free-flowing, "fluffy" meal that suppliers produce rather risking an in-house grind that may yield a mass of walnut butter. Which is a fantastic ingredient in its own right—but the topic for a whole other R&D discussion.

[1] Please note: One ounce of walnuts provides 18g of total fat, 2.5g of monounsaturated fat, 13g of polyunsaturated fat, including 2.5 grams of alpha linolenic acid - the plant based omega-3 (http://www.nal.usda.gov/fnic/foodcomp/cgi-bin/list_nut_edit.pl)

-- Rachel Zemser