The pericarp is the wall of a ripened plant ovary, the tissue that encloses the seed and forms the major part of bran in cereal grains. In wheat, it comprises several fibrous layers, the epicarp, mesocarp, and endocarp, that protect the starchy endosperm and germ within. Milling strips the pericarp away with the bran to produce white flour, removing most of the grain’s fibre, B vitamins, minerals, and phytochemicals along with it, which is why wholegrain products are nutritionally superior. In fruits, the pericarp differentiates into the skin, flesh, and stone layers, the exocarp, mesocarp, and endocarp, of peaches, citrus, and berries. Understanding pericarp structure guides processing: pearling barley removes it gradually, parboiling drives nutrients inward before milling removes it, and bran’s functionality in baking depends on its particle size.