Global sales of gluten-free bread and other bakery products have risen sharply over the past ten years, Euromonitor reports, with the UK, Germany, Netherlands and France leading the way in Europe. Apart from purchases by consumers who are gluten intolerant, it seems that a general health trend has arisen around the gluten-free market.
A main reason is the general improvement in quality, primarily brought about by new processing knowledge. But, despite this, there is still a long way to go before gluten-free bread has comparable sensory properties to standard bread. Gluten, it had turned out, is a particularly difficult ingredient to replace.
A protein composite in wheat and related grains such as rye, gluten is responsible for forming the elastic network that holds bread dough together, binding water and air to secure volume and crumb structure. If gluten is simply taken out, the dough mix has no structure or handling properties, resulting in a very compact bread that rapidly goes stale.
Many ways to go gluten-free
Efforts to substitute gluten have taken us bakers down very difficult routes. Everyone has their own approach, employing all kinds of flours and starches, hydrocolloids, fibers, proteins, leveling agents and other ingredients, often in very complicated recipes. Not surprisingly, there is a huge variation in the quality of the final bread.
Our work with gluten-free formulations at DuPont has focused on screening flours and starches and testing hydrocolloids. What we are looking for is a good gluten-free system that performs well in a simple test recipe.
Flour and starch screening
One of our initial studies tested the specific baking potential of flours and starches in a recipe optimized with 15% added gluten and an improver system. By testing with gluten in the first instance, we established the baseline quality that we are now trying to match with a gluten alternative.
The screening process revealed that gluten-free wheat starch gave the best result, providing the basis for further tests with varying doses of hydrocolloids, emulsifiers, proteins, enzymes and fats and oils.
Hydrocolloids under test
Of these ingredients, hydrocolloids are especially interesting due to their ability to mimic the visco-elastic properties of gluten, providing viscosity, water binding, dough stability and a gel to trap the CO2 produced by yeast fermentation.
We have investigated the performance of several gums, including xanthan, guar, locust bean and cellulose gum. This has demonstrated their ability to add structure, volume and stability to gluten-free bread. Our test recipe based on 100% wheat starch, skimmed milk powder and a hydrocolloid blend has given us our best result so far.
Further trials with emulsifiers such as mono- and diglycerides of fatty acids have highlighted their ability to add extra stability while improving the crumb structure and softness of gluten-free bread during shelf life.
Still no answer
Whether you prefer to work with a gluten-free batter or a kneadable dough, there is still no standard answer to gluten replacement. Ingredient interactions are unpredictable, which means optimization of individual recipes is a must. Although gluten-free bread is today undoubtedly more enjoyable to eat, a gluten alternative that can provide precisely the same bread taste, texture and shelf life has yet to be found. Our efforts continue.