Wheat Gluten

Gluten is a storage protein found in cereals like triticale, rye, barley; but perhaps the most well known is wheat gluten. Gluten is made up of the monomeric peptide gliadin and the polymeric peptide  glutenin. Some individuals suffer from Celiac disease- an allergic response to gluten. Hence, the advent of “gluten free” claims on many different food products. Wheat gluten is used in many different ways, for both, food and non-food uses.

Bakery: Perhaps the oldest and best known functional use of gluten is in bread making. Although insoluble in water, gluten can bind approximately twice its weight water giving rise to a hydrated viscoelastic mass. This property of gluten helps  hold together the dough used for making bakery products. In addition, owing to its elasticity, gluten can stretch and expand and help trap in the carbon dioxide bubbles generated during fermentation of bread.  

Meat analogues: When subjected to extrusion processing, gluten proteins align to form microfibrils that in turn form a macroscopic fibrous structure. These microfibrils upon hydration swell and give a fleshy appearance to the texturized wheat gluten. The viscoelastic properties of gluten also enable it to be moulded into a desired shape. This property has been harnessed in making meat or sea food replacements. Gluten may be processed and presented as  high value seafood like crab meat. The extrusion process works on gluten to give it the mouth feel and texture of meat.

Condiment: Although gluten is lacking in some essential amino acids like leucine and threonine, it has a high proportion of glutamine. By chemical methods such as deamidation, this glutamine can be converted to glutamic acid. Wheat gluten has thus been used to produce monosodium glutamate or a liquid similar to soy sauce.

Fortification and breakfast cereals: Wheat gluten is used as a low cost additive to fortify flours having low protein content. Even breakfast cereals make use of wheat gluten to increase their protein content and give a characteristic texture to the product. The most notable amongst these is the Kellog’s K cereal which employs wheat gluten as one of its ingredient. Due to its ability to bind water, gluten has been used as a binding agent for fruit purees used as fillings in nutritional fruit bars. It has also been used in producing synthetic cheese and as replacement for sodium caseinate in imitation cheese products.

Non-food uses: Gluten also has many non-food applications such as its use in adhesive bandages, biodegradable materials and edible coatings. Peptides from gluten have also found use in cosmetics. 

Reference:

Day et al, Wheat-gluten uses and Industry needs, Trends in Food Science & Technology, 17 (2006) 82–90