Development and Structure of the Corn Kernel

The corn kernel is the fruit or caryopsis borne in the female inflorescence of the plant, which contains the embryo and storage tissues designed to create upon germination the new seedling and generation plant. Kernels are constituted by three major anatomical parts: pericarp, germ, and pericarp and contain high levels of starch, protein, oil, and other nutritionally valuable substances for humankind. Within each type of corn (see Chapter 10), important variations exist in endosperm hardness, pericarp, endosperm color, type of starch, and kernel size. In order to understand the relevant changes that corn undergoes during processing, it is essential to comprehend the macro- and microstructure and the basic composition of each anatomical part of the caryopsis. Better understanding of the macro- and microstructural features and properties of corn improves our ability to utilize it in many food and industrial products. It is also necessary to achieve optimal quality preservation in harvesting, drying, storing, and processing. Furthermore, the structure and the appearance of modern corn have been modified by breeding and the knowledge of the relationships among structural component is fundamental for plant breeding, wet and dry-milling, and food processors. This chapter reviews relevant information on the physical properties of the corn kernel and the constitution and functionality of its anatomical parts and is mainly focused on to establish a solid foundation of the current state of knowledge of the anatomy and architecture of the corn kernel. Ultimately, the understanding of the microstructural features of the anatomical parts of the kernel is of utmost importance for all industrial segments because they are closely related to yield and quality of end products.