What are the three types of gluten? Understanding the proteins in wheat, barley, and rye

November 15, 2025 •

4 min read

While many ask, 'What are the three types of gluten?', the simple answer is there is no such classification; gluten isn't a single substance but a complex mixture of storage proteins. Specifically, in wheat, the two major protein groups are gliadins and glutenins, which combine to form the unique viscoelastic network known as gluten when mixed with water.

Quick Summary

Gluten is not a single compound but a protein mixture, predominantly gliadins and glutenins in wheat. These protein compositions differ slightly across gluten-containing grains like barley and rye, impacting baking properties and celiac disease reactions.

Key Points

Two Primary Protein Groups: In wheat, gluten is a complex formed from two distinct protein groups: gliadins and glutenins.
Gliadin Adds Stretchiness: Gliadin is a monomeric protein that contributes viscosity and extensibility, or stretchiness, to dough.
Glutenin Adds Strength: Glutenin is a polymeric protein that forms a network responsible for the elasticity and strength of the dough.
Different Grains, Different Names: The gluten-forming proteins in barley are called hordeins, while those in rye are called secalins.
Formation Requires Water and Movement: Gluten is not pre-existing in flour; it forms when gliadin and glutenin are mixed with water and agitated through kneading.
Impact on Health: These proteins, particularly certain gliadin peptides, are responsible for triggering immune responses in individuals with celiac disease.

Demystifying the 'Three Types of Gluten' Question

The idea that there are 'three types of gluten' is a common misconception, likely stemming from the fact that three grains—wheat, barley, and rye—are the most common sources of gluten. In reality, gluten is a complex composite of storage proteins, and its specific makeup varies depending on the grain. The unique properties of dough, like its elasticity and extensibility, come from the interaction of two major protein families: gliadins and glutenins, primarily found in wheat. This article will clarify the real components of gluten and how they differ among various grains.

The Core Components of Wheat Gluten: Gliadin and Glutenin

When wheat flour is mixed with water and kneaded, two main protein groups, gliadin and glutenin, intertwine to form the gluten network. These proteins have distinct roles that contribute to the final product's texture and structure.

Gliadin: The Extensible Contributor

Gliadin proteins are generally monomeric, meaning they exist as single-chain polypeptides. This structure gives dough its viscosity and extensibility, allowing it to stretch and spread. Gliadins can be further subdivided based on their amino acid sequences and molecular weight into alpha/beta-, gamma-, and omega-gliadins. It is important to note that specific gliadin peptides, particularly from the alpha-gliadin group, are known to trigger the immune response in individuals with celiac disease.

Glutenin: The Elastic and Strong Framework

In contrast to the single-chain gliadins, glutenins are much larger, aggregated proteins linked by inter-chain disulfide bonds. These long, polymeric chains provide the gluten network with its strength and elasticity, allowing dough to snap back and hold its shape. Glutenins are categorized into High-Molecular-Weight (HMW) and Low-Molecular-Weight (LMW) subunits, with the HMW subunits playing a critical role in determining dough's final elasticity and strength.

The Diverse Protein Families in Other Grains

The protein groups that make up gluten vary slightly in name and composition across different gluten-containing grains. These homologous proteins all belong to a larger family of storage proteins known as prolamins and glutelins.

Wheat: Contains gliadins and glutenins.
Barley: The corresponding proteins are called hordeins.
Rye: Contains homologous proteins known as secalins.
Triticale: A hybrid of wheat and rye, triticale contains a mixture of their respective prolamins.

Although the proteins are named differently, the prolamins in wheat, barley, and rye all contain similar genetic sequences that can cause an adverse immune response in individuals with celiac disease. The specific nature and severity of the reaction may depend on the grain, but all must be avoided on a strict gluten-free diet.

How Gluten Formation Affects Baking

The interplay between gliadin and glutenin is fundamental to baking. When water is added to flour, these proteins absorb moisture and begin to uncoil. Kneading the dough then aligns and stretches these protein chains, creating the complex, elastic gluten network that traps gas produced by yeast during fermentation. This network is what allows bread to rise, provides structure, and gives the final baked good its characteristic chewiness and texture. For products requiring less chewiness, like delicate cakes, low-protein flour and minimal mixing are used to limit gluten development.

How Gliadin and Glutenin Differ


Characteristic	Gliadin	Glutenin
Structure	Monomeric (single-chain) polypeptide	Polymeric (aggregated) chains of polypeptides
Molecular Weight	Lower (e.g., 28,000–55,000)	Higher (from 100,000 to over 10 million)
Primary Function	Provides viscosity and extensibility (stretchiness)	Provides elasticity and strength
Network Role	Introduces viscosity and helps hold structure	Forms the backbone of the elastic protein network
Solubility	Soluble in aqueous alcohols	Insoluble in alcohol; subunits are soluble after reducing disulfide bonds

Gluten-Related Disorders and Alternatives

The varying properties of gluten from different grains can result in different reactions for those with gluten-related disorders. For individuals with celiac disease, non-celiac gluten sensitivity, or wheat allergy, complete avoidance of these proteins is necessary.

The food industry has developed numerous naturally gluten-free alternatives to replace these grains. These include grains like quinoa, rice, corn, and buckwheat, along with flours from nuts, seeds, and legumes. These alternatives require different baking techniques and fillers, like gums, to achieve textures similar to their gluten-containing counterparts. For those with severe gluten sensitivities, it's crucial to be mindful of cross-contamination, as even trace amounts can cause symptoms.

Conclusion

To answer the question, "What are the three types of gluten?" accurately, it's necessary to move beyond the grains themselves and understand the underlying protein science. Rather than just three types, gluten is a complex family of proteins, primarily gliadins and glutenins in wheat, and homologous proteins in barley and rye. Their unique molecular structures are what create the distinct baking properties we rely on, but also what triggers serious health issues for those with sensitivities or celiac disease. By recognizing the true nature of these protein networks, consumers and bakers can make more informed decisions about their ingredients and dietary needs.

Learn more about celiac disease and gluten-free living from the Celiac Disease Foundation.

Frequently Asked Questions

Gluten is not a single protein, but a complex composite of storage proteins found in the endosperm of grains like wheat, barley, and rye. It is composed primarily of gliadins and glutenins.

Gliadin is a monomeric protein that gives dough its viscosity and extensibility, or stretchiness. Glutenin is a polymeric protein, linked by disulfide bonds, that provides the dough with elasticity and strength.

No, only certain grains contain gluten-forming proteins. The most common are wheat, barley, and rye. Grains like corn, rice, and quinoa are naturally gluten-free.

While the proteins are called hordeins in barley and secalins in rye, they are homologous to the gliadins and glutenins in wheat. Their protein structures contain sequences that trigger a similar autoimmune response in genetically predisposed individuals with celiac disease.

Gluten-free flour is made from grains like rice, corn, or buckwheat, which do not contain gliadin and glutenin. It often requires additives like gums or starch to replicate the binding and elastic properties that gluten provides.

Gluten itself provides some protein, and the whole grains that contain it (like wheat) offer a range of nutrients. However, removing gluten from the diet does not necessarily reduce nutritional value, especially with careful substitute choices.

While some industrial processes can reduce gluten content, it's impossible to completely remove it from grains like wheat, barley, and rye. For those with celiac disease, relying on certified gluten-free products is the only safe option.

Yes, kneading develops the gluten network by stretching and aligning the gliadin and glutenin proteins. More kneading creates a stronger, more elastic network, while less kneading results in a more tender product.

The 33-mer peptide is a specific fragment of alpha-gliadin that is particularly resistant to digestion and highly immunogenic, meaning it is a significant trigger for the immune response in celiac disease.