Triticum aestivum is the scientific designation for common wheat, also known as bread wheat. This cereal grain is one of the most widely cultivated and consumed crops globally. Its adaptability to diverse environments makes it a foundational ingredient in countless food products.
The Origins of Common Wheat
Common wheat is not a naturally occurring wild plant but resulted from a long domestication process and natural hybridization events involving different grass species. Its history traces back to the Fertile Crescent region of West Asia, with archaeological evidence suggesting initial cultivation around 9600 BC. This area, stretching across parts of the Middle East, is recognized as the birthplace of agriculture, where early human societies transitioned from foraging to sedentary farming.
Around 7,000 to 10,000 years ago in Transcaucasia, domesticated emmer wheat hybridized with wild goatgrass (Aegilops tauschii), giving rise to hexaploid common wheat. This new species possessed traits more favorable for human cultivation, such as non-shattering spikes that retained grains for easier harvesting. The domesticated form of wheat then spread from the Middle East to North Africa, Europe, and East Asia during prehistoric periods, eventually reaching North America in the 16th century.
Genetic Makeup
The genetic structure of Triticum aestivum is complex, classifying it as an allohexaploid organism. This means it possesses six sets of chromosomes, specifically 42 chromosomes in total, arranged into three distinct subgenomes labeled A, B, and D.
The A and B subgenomes originated from a domesticated tetraploid progenitor, wild emmer wheat (Triticum turgidum subsp. dicoccoides). The third subgenome, D, was contributed by the wild diploid goatgrass Aegilops tauschii. This combination of genetic material from multiple ancestors provided Triticum aestivum with broad genetic diversity, contributing to its adaptability to a wide range of climates and its unique baking qualities, including gluten formation.
From Field to Flour
The journey of Triticum aestivum from a harvested crop to a food ingredient involves several agricultural and industrial steps. Wheat is planted as either winter wheat, sown in autumn for harvest the following summer, or spring wheat, planted in spring for a late summer harvest. After the grains mature, they are harvested using specialized machinery that separates the kernels from the rest of the plant material.
Following harvest, the wheat kernels undergo a milling process to be transformed into flour. Modern roller mills separate the wheat kernel into its three primary components: the outer bran layers, the germ, and the starchy endosperm. The process begins with cleaning and conditioning the grain, followed by “break” rollers that gradually open the wheat kernel, separating the endosperm from the bran and germ. The separated endosperm particles then pass through smooth reduction rolls to be finely ground into white flour. Different types of flour are produced based on which parts of the kernel are included; whole wheat flour retains all three components, while white flour is primarily derived from the endosperm after the bran and germ have been removed.
Global Food Staple
Common wheat serves as a fundamental component of diets worldwide, forming the basis for numerous food products. It is extensively used in the production of bread, pasta, noodles, pastries, breakfast cereals, and various baked goods. Beyond its versatility in cooking, Triticum aestivum provides nutritional value, acting as a major source of carbohydrates and protein.
A significant aspect of wheat’s utility in food preparation is the presence of gluten, a complex of proteins primarily composed of gliadins and glutenins. Gluten is responsible for the elasticity and extensibility of dough, allowing it to rise and hold its shape during baking. While beneficial for food texture, gluten can trigger immune responses in some individuals. Celiac disease, an autoimmune disorder affecting approximately 1% of the general population in developed countries, involves an immune reaction to gluten that damages the small intestine. Other conditions, such as non-celiac gluten sensitivity and wheat allergies, also involve adverse reactions to wheat proteins, necessitating dietary considerations for affected individuals.