Gluten is a complex mixture of hundreds of related but distinct proteins, mainly gliadin and glutenin (more than 80%). Similar storage proteins exist as secalin in rye, hordein in barley, and avenins in oats and are collectively referred to as “gluten.” The gliadins (ω-, αand γ type) are relatively small molecules that are soluble in alcohols, which may act as a plasticizer in dough systems.
Gluten has four important properties: it absorbs twice its weight in water, it is sticky, it is extensible; this means it will stretch when pulled and it is elastic; when stretched it will return to near its original size.
Gluten is shown to be polymers with molecular weights (MW) in the millions, formed from smaller proteins.
Wheat flour quality is directly related to the wheat gluten formed by mixing the flour with water and with the use of appropriate application of mechanical work to form a viscoelastic network, whose structure is the basis for bakery products and pasta.
The wheat gluten proteins correspond to the major storage proteins that are deposited in the starchy endosperm cells of the developing grain. These form a continuous proteinaceous matrix in the cells of the mature dry grain and are brought together to form a continuous viscoelastic network when flour is mixed with water to form dough.
Gluten may be defined as the ‘cohesive, visco-elastic proteinaceous material prepared as a by-product obtained by isolation of starch from wheat flour. A biological definition might include the origins of the gluten–protein complex as being derived from the ‘storage proteins of the wheat grain’.
Gluten in wheat flour: Composition and properties
