The endosperm consists of two distinct cell types: aleurone cells, forming the outermost layer with thick walls, and central starchy endosperm cells that are rich in starch and gluten proteins.
The aleurone layer, a single layer of living cells, acts as a barrier between the starchy endosperm and the germ and is abundant in essential nutrients such as minerals, vitamin B, and protein.
The starchy endosperm is the main and largest part of the grain, serving as a storage compartment to provide energy for the germinating plant. Within the endosperm cells, proteins and starch are stored, resulting in a unique and highly dense structure.
The composition of wheat endosperm varies depending on its source, typically containing around 68 to 76% starch and 6 to 18% protein. It holds the highest proportion of protein, carbohydrates, iron, and B-vitamins like riboflavin and niacin, making it a valuable source of nutrients and soluble fiber.
Constituting approximately 83% of the kernel weight, the endosperm is the primary source of white endosperm flour. In white flour, proteins play a crucial role as binding agents, ensuring the cohesion of starch granules within the endosperm.
Endosperm Composition: Nutrients and Structure
