What is the protein in bread called?

According to the Celiac Disease Foundation, approximately 1 in 100 people worldwide are affected by celiac disease, an autoimmune condition triggered by the ingestion of gluten. But for those who don't have this sensitivity, what is the protein in bread called that contributes to its classic texture and structure? The term for this protein network is gluten, which is formed from two main components in wheat flour: glutenin and gliadin.

Quick Summary

The protein in bread is called gluten, a network formed when water is combined with two separate proteins found in wheat flour: glutenin and gliadin. Glutenin provides elasticity, allowing dough to stretch and snap back, while gliadin gives it extensibility, enabling it to be stretched easily. This network is essential for the structure and texture of baked goods.

Key Points

• Gluten is the main protein in bread: The term 'gluten' refers to the unique protein complex formed from glutenin and gliadin in wheat flour when mixed with water.

• Glutenin provides elasticity: This protein is responsible for the dough's ability to resist stretching and snap back, contributing to the bread's structure and chewiness.

• Gliadin provides extensibility: This protein gives the dough its stretchiness, allowing it to be shaped without tearing.

• The gluten network traps gas: The stretchy gluten framework holds onto the carbon dioxide bubbles produced by yeast, allowing the bread to rise and achieve its characteristic texture.

• Protein content affects baked goods: Higher protein flours create a stronger gluten network for chewy breads, while lower protein flours are used for tender products.

• Health conditions are linked to gluten: Individuals with celiac disease, non-celiac gluten sensitivity, or wheat allergy must avoid or limit gluten.

• Not all bread has gluten: Gluten-free alternatives made from other grains are available for those with sensitivities.

Understanding the Gluten Network

To appreciate the intricate science behind a simple loaf of bread, one must understand how the protein network known as gluten is created. Gluten is not pre-existing in flour but is formed when water is added to wheat flour containing glutenin and gliadin, and then mixed or kneaded. This process develops the gluten network, giving the dough viscoelastic properties – the ability to stretch and hold shape. The gluten network traps carbon dioxide from yeast fermentation, causing dough to rise and creating bread's airy, chewy texture. Higher protein flour leads to stronger gluten development, affecting the type of baked good it's best suited for.

The Dynamic Duo: Glutenin and Gliadin

Gluten is primarily composed of gliadin and glutenin, each contributing distinct characteristics to the dough.

• Glutenin: Provides elasticity and strength, allowing dough to resist stretching and snap back. Its complex structure is formed by molecules linking together via disulfide bonds.
• Gliadin: Adds extensibility and viscosity, enabling dough to stretch and shape without tearing. It acts as a plasticizer within the gluten network.

Comparing Gluten and Other Wheat Proteins

Wheat flour contains other non-gluten proteins classified by solubility.

Protein Type	Primary Function	Solubility in Water	Location in Grain
Gluten Proteins (Gliadin & Glutenin)	Provides structure, elasticity, and chewiness to bread dough	Insoluble	Concentrated in the starchy endosperm
Albumins & Globulins	Metabolic enzymes, nutrients for embryo, defense against pests	Soluble	Primarily in the germ and outer layers
Prolamins	Storage proteins (includes gliadins and glutenins)	Sparingly soluble in water or dilute salt	Primarily in the endosperm

Health Implications of Gluten

Gluten causes issues for individuals with specific health conditions. Celiac disease is an autoimmune disorder where gluten damages the small intestine. Non-celiac gluten sensitivity (NCGS) involves symptoms without intestinal damage. Wheat allergy is an immune reaction to any wheat component. For those who cannot consume gluten, gluten-free bread alternatives use non-wheat flours and additives to mimic gluten's function. However, gluten is a valuable protein source for most people.

Conclusion

The protein in bread is called gluten, a network of gliadin and glutenin that forms when flour and water are combined and manipulated. This network is crucial for bread's structure, elasticity, and texture, allowing it to rise during baking. While essential for traditional bread-making, gluten poses health issues for those with conditions like celiac disease, driving the development of gluten-free options. Understanding gluten reveals the fascinating chemistry behind this staple food.

For an in-depth visual explanation of how gluten forms in dough, consider watching this video from the Institute of Food Science and Technology.

Frequently Asked Questions

Is gluten a single protein?

No, gluten is not a single protein but a composite network formed from two separate proteins found in wheat flour: gliadin and glutenin.

Why is gluten important for baking bread?

Gluten gives bread dough its elasticity and extensibility, allowing it to hold its shape and trap gas bubbles from yeast. This is what makes the bread rise and gives it a light, airy, and chewy texture.

What grains contain gluten?

Gluten-containing grains include wheat (all species), barley, and rye. Oats are naturally gluten-free but can be contaminated through shared processing equipment.

Can people with celiac disease eat bread?

Individuals with celiac disease cannot safely consume traditional bread containing wheat, rye, or barley. They must opt for certified gluten-free breads made from alternative flours.

How is the gluten network formed in bread?

The gluten network is formed when water is added to flour, activating the gliadin and glutenin proteins. The mechanical action of kneading or mixing then links these proteins together.

What is the difference between bread flour and all-purpose flour?

Bread flour has a higher protein content (12-14%) than all-purpose flour (11.7%), meaning it has a greater potential to develop a strong gluten network, resulting in chewier bread.

What is the role of gliadin and glutenin in bread?

Gliadin provides the extensibility (stretch) while glutenin provides the elasticity (snap back) to the dough. The balance of these two is key to the final texture of the bread.