The Role of Gluten in Baking: Structure, Function, and Alternatives

Gluten is a vital component in flour, playing a key role in providing the structure, texture, and elasticity essential for various baked goods. It consists mainly of two proteins: glutenin and gliadin, which together account for about 80% of the protein content in flour. These proteins form a complex network when combined with water, contributing to the unique properties of dough that make it suitable for baking.

Glutenin is responsible for the dough’s strength and elasticity. It comprises long, coiled protein molecules that can stretch and contract, enabling the dough to withstand kneading and the rising process. This elasticity is crucial for producing bread with a chewy texture. Gliadin, on the other hand, enhances the dough’s extensibility, allowing it to stretch without breaking. The balance between glutenin and gliadin determines the final texture of baked goods, influencing whether they are tender, firm, or chewy.

The gluten formation process begins when flour is hydrated, activating glutenin and gliadin. Mechanical action, such as kneading or mixing, further aligns and links these protein molecules, creating a strong and flexible gluten network. This network traps gas produced by yeast or chemical leavening agents, such as baking powder, allowing the dough to expand and rise. During baking, the heat solidifies the gluten structure, resulting in a stable, airy, and well-textured final product. This process is particularly crucial in bread-making, where gluten development dictates the crumb structure and chewiness of the loaf.

While gluten is indispensable in traditional baking, it poses health concerns for individuals with gluten-related disorders. Celiac disease, an autoimmune condition affecting about 1% of the global population, causes severe reactions to gluten, leading to damage in the small intestine. Non-celiac gluten sensitivity (NCGS) also affects many people, causing symptoms like bloating, fatigue, and digestive issues without the autoimmune response. As awareness grows, the market for gluten-free alternatives has expanded, offering flours from rice, almond, coconut, and other sources to cater to dietary needs.

Despite the rise of gluten-free diets, gluten remains a fundamental element in baking, ensuring the desired texture and structure of numerous products. Advances in food science continue to explore ways to improve gluten alternatives, enhancing the quality of gluten-free baked goods while maintaining the traditional characteristics of wheat-based products.
The Role of Gluten in Baking: Structure, Function, and Alternatives

Prolamins in wheat

Wheat proteins are divided into two major categories: prolamins including gliadins and glutenins, and non-prolamins consisting of water–soluble albumins and salt soluble globulins.

Prolamins are a group of proteins that defined by their solubility in alcohol/water mixture. They are the proteins in wheat, barley and rye that are harmful to persons with celiac disease.  Wheat, rye and barley prolamins are called gliadin, secalin and hordein, respectively.

Wheat contains two types of prolamins: the monomeric gliadin proteins and the polymeric glutenin proteins. Together, these proteins, being the major storage proteins of the grain endosperm, make up more than 75% of the total protein of wheat.

Traditionally, the gliadin fraction has been considered as the prolamin fraction of wheat protein, defined on the basis of its extractability in aqueous alcohol solution and its very high contents of proline and glutamine.

Glutenin has been considered as belong to a different protein fraction, the glutenin fraction, defined by its insolubility in alcohol solution and by its extractability in dilute acid or alkali.
Prolamins in wheat