Its importance as a primary food crop is associated with various features, and a notable aspect is the exceptional ability of its protein to form a flexible, cohesive mass when mixed with water.
The wheat kernel comprises three main components: bran, germ, and endosperm. The endosperm, the starchy part of the kernel remaining after the removal of bran and germ, constitutes the white portion.
The wheat endosperm, containing starch ranging from 68 to 76% and protein from 6 to 18%, serves as the foundation for white flour. In this context, proteins act as binding agents, holding starch granules together in the endosperm.
Approximately 80% of the protein in flour consists of glutenin and gliadin. When combined with water and integrated into dough, these proteins give rise to the elastic substance known as gluten.
Gluten displays plasticity, strength, and elasticity, allowing it to deform under pressure, resist deformation, and return to its original form when pressure is released.
Other proteins present in white flour include enzymes, particularly amylase or diastase, responsible for breaking down starch into essential simple sugars for yeast fermentation.
Wheat proteins are categorized based on their extractability and solubility in various solvents:
- Albumin: soluble in water
- Globulin: insoluble in pure water but soluble in dilute NaCl solution, becoming insoluble at high NaCl concentrations
- Gliadin: soluble in 70% ethyl alcohol
- Glutenin: soluble in dilute acid or sodium hydroxide solutions
The levels of protein in wheat play a crucial role in determining the prices of hard red spring wheat, especially in regions like Minnesota, Montana, North Dakota, and South Dakota. Higher protein content commands elevated prices in the market.
Wheat Protein Properties
